Prevalence and determinants of Non-Nutritive Sucking on ...
Transcript of Prevalence and determinants of Non-Nutritive Sucking on ...
Prevalence and determinants of Non-
Nutritive Sucking on Anterior Open
Bite in Children Attending Primary
School
Liyana Tanny
A dissertation submitted in requirements for the research degree
Masters of Philosophy (Honours)
Faculty of Science
School of Dentistry and Health Sciences
Charles Sturt University
Wagga Wagga
Australia
January 2020
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STATEMENT OF AUTHENTICITY
I, Liyana Tanny, hereby declare that this submission is my own work and that, to
the best of my knowledge and belief, it contains no material previously published
or written by another person nor material which to a substantial extent has been
accepted for the award of any other degree or diploma at Charles Sturt University
or any other educational institution, except where due acknowledgement is made
in the dissertation. Any contributions made to the research by colleagues with
whom I have worked at Charles Sturt University or elsewhere during my
candidature is fully acknowledged.
I agree that the dissertation be accessible for the purpose of study and research
in accordance with the normal conditions established by the University Librarian
for the care, loan and reproduction of the thesis.
07/01/2020
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Signature Date
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ACKNOWLEDGMENTS
I would like to first and foremost thank the supreme power the Almighty God
(Allah) who has guided me throughout my academic life and immersed me with
blessings which allowed me to be where I am today.
I want to take this opportunity to express my sincere gratitude to my supervisors
who have guided and mentored me throughout this journey, without their valuable
input and complete support, this would not have been possible. Dr Boyen Huang
for his initial support in commencing this project and his valuable ideas and
concepts for making this project a reality. Dr Geoff Currie for his ongoing and
unfailing support when times get rough and his exceptional input into the
statistical analysis of this project. Dr Ashraf Shaweesh, for his valuable and
knowledgeable input on the content of this dissertation.
I am extremely grateful to my parents (Mustafa & Nariman) for their unconditional
love and ongoing support. Their limitless care and sacrifice in educating me and
preparing me for my future has been tremendous. I want to thank my parents-in-
law (Hazim & Maiwaa) for their continuous support throughout this journey.
I want to express my deepest gratitude to my loving husband and soulmate,
Ahmed Al-Humairi. The holistic support he provided me with is exceptional and
everlasting, and without him this would not be a reality. Lastly, I would like to
thank my beautiful children, Miral and Hamza who have been a big part of this
journey.
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ABSTRACT
Introduction
Anterior open bite (AOB) is a malocclusion that is depicted by lack of contact
between the anterior teeth when the jaw is in maximum closure. It is one of the
most complex malocclusions to treat and manage and it has been proven to affect
speech, mastication and aesthetic appearance of the face. Aetiological factors of
anterior open bite include unfavourable growth capacity and heredity, enlarged
anatomic structures such as the tongue, tonsils or adenoids and environmental
factors involving non-nutritive sucking (thumb/pacifier). The reported prevalence
suggests that there is inconsistency in the extent of occurrence frequency of this
occlusion as well as aetiological factors associated. The aim of this current study
was to investigate the prevalence of non-nutritive sucking habits and
determinants of AOB in Australian children aged seven to 12 years.
Methods
A cross-sectional study was carried out involving 208 primary school children in
the regional town of Orange, New South Wales, Australia. A questionnaire
addressing sociodemographic data, medical conditions known to be associated
with malocclusion, data of nutritive and non-nutritive sucking habits, and
illustrations of different malocclusions to be selected for the child was
administered to parents/guardians of children enrolled in primary schools in
Orange New South Wales. Data analysis involved descriptive statistics,
inferential, multivariate and neural analysis. Chi square tests (p <0.05) and odds
ratio calculations were used for inter-variable comparisons. The impact of non-
nutritive sucking and duration of non-nutritive sucking on anterior open bite were
analysed using neural analysis.
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Results
According to the information provided by the parents, the prevalence of AOB was
24.1% and of those AOB cases, 76% reported to have carried out thumb-sucking
habits. No statistical significance was noted between the type of malocclusion
and child’s aged at presentation (P=0.1786), the child’s gender (P=0.918) or
whether the child had orthodontic intervention (P=0.1217). Of the children who
commenced thumb-sucking at age two to five years, 100% had developed an
AOB. No child with a duration of six months or less of thumb-sucking had
developed AOB. Children who were bottle-fed were 1.9 times more likely to
develop AOB than breastfed children. Children whose parents had lower levels
of education were three times more likely to develop an abnormal bite. Neural
analysis confirmed that both thumb-sucking and duration of thumb-sucking
presented the highest association with anterior open bite.
Conclusions
Socioeconomic factors and sleeping issues were linked to malocclusions. A
significant relationship between abnormal bite and the need for tonsillectomy
and/or adenoidectomy surgery was identified. Thumb-sucking and duration of
thumb-sucking represented the strongest predisposing factors for anterior open
bite. Breastfeeding provided a protective effect against the development of an
abnormal bite, and conversely, bottle-fed children were more likely to develop an
abnormal bite. Longer duration of breastfeeding and cessation of non-nutritive
sucking habits, particularly thumb-sucking needs to be encouraged.
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TABLE OF CONTENTS
Statement of Authenticity II
Acknowledgements III
ABSTRACT IV
List of Figures IX
List of Tables X
List of Abbreviations and Acronyms XI
1 BACKGROUND 1
1.1 Introduction 2
1.2 Dental Occlusion 4
1.2.1 Definitions and Classifications 5
1.2.2 Structures Involved in Occlusion Development 9
1.2.3 Development of Dental Occlusion 10
1.3 Malocclusion 14
1.3.1 Anterior Open Bite (AOB) 14
1.3.1.1 Prevalence of AOB 17
1.3.1.2 Development of AOB 20
1.3.1.3 Aetiology of AOB 21
1.3.1.3.1 Skeletal 22
1.3.1.3.2 Oral Habits 23
1.3.1.3.3 Other Aetiological Factors 24
1.3.1.4 Treatment of AOB 24
1.3.2 Other Malocclusions 27
1.4 Factors Affecting Malocclusion 29
2 LITERATURE REVIEW 31
2.1 Open Bite Malocclusion 32
2.1.1 Prevalence of AOB 34
2.1.2 Prevalence of Non-Nutritive Sucking Habits 35
2.1.3 Correlations of AOB and Determinant Factors 37
2.1.4 Treatment Options 39
2.1.5 Burdens of AOB on the Community 43
2.2 State of the Problem 44
VII
3 METHODS 46
3.1 Research Question 47
3.2 Aims and Objectives 47
3.3 Study Variables 47
3.4 Overview of Method 47
3.5 Data Collection 48
3.6 Selection Criteria 50
3.7 Statistical Analysis 52
3.8 Ethical Considerations 53
4 RESULTS 54
4.1 Descriptive Analysis 55
4.2 Inferential Analysis 59
4.3 Multi-Variate Analysis 62
4.4 Neural Analysis 65
4.4.1 Combined Deep Bite and Open Bite 65
4.4.2 Open Bite Only 68
4.4.2.1 Method 69
4.4.2.2 Results 71
5 DISCUSSION 73
5.1 Demographics 75
5.2 Questionnaire 78
5.3 Prevalence 80
5.4 Non-Nutritive Sucking 84
5.5 Feeding Modalities 86
5.6 Sleeping Issues 89
5.7 Limitations 90
5.8 Recommendations 92
5.9 Conclusions 93
REFERENCES 95
APPENDICES 111
VIII
LIST OF FIGURES
1.1 An illustration of facial and intra-oral photographs displaying the features of a patient with AOB (Kim & Sung, 2018, p. 284).
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1.2 An illustration of the temporomandibular joint showing the difference in mandibular position between a CO (solid line) and CR (broken line) (Shildkraut, Wood, & Hunter, 1994, p. 336).
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1.3 Functional anatomy of the temporomandibular joint illustrating the position of the mandible to the maxilla with the intra-articular disc is in place (Helland, 1980, p. 147).
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1.4 Representation of occlusion development of the first molar with illustration of the terminal plane at approximately 5 years of age, and initial contact at approximately 6.5 years and final occlusion at about 12 years (Moyers, 1973, p. 135-137).
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1.5 Representation of an open-bite pattern using a cephalometric tracing of landmarks and planes (Cangialosi, 1984, p. 30).
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1.6 This diagnostic flow chart demonstrates the possibilities and relationships between skeletal and dental relationships in open bite malocclusion (Ngan & Henry, 1997, p. 91-98).
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2.1 Comparison between ideal class I anterior occlusion (A) and anterior open bite malocclusion (B) (Ackerman & Proffit, 1969, p. 445).
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2.2 An illustration of AFH: Anterior facial height, and PFH: Posterior facial height, the objective of treatment is to maintain AFH and to improve PFH (Horn, 1992, p. 181).
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2.3 Maxillary palatal crib. The extensive dimension vertically allows ample incorporation of the open-bite region (Torres et al., 2006, p. 612).
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2.4 Lingual bonded spurs. a and b are examples of lingual bonded spurs bonded to the maxillary and mandibular incisors. C is an example of lingual bonded spurt appliance used to correct anterior tongue posture or digit-sucking habits. d the same subject as in photograph a and b with 8 spurs bonded to the upper and lower incisors. Note the difference in aesthetic between the spurs in and b in comparison to c (McRae, 2010, p. 6).
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2.5 An illustration of chin cup therapy to correct malocclusion which led to the decrease of the gonial angle (Torres et al., 2006, p. 612).
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4.1 Incidence of various bites in the sample population (centre), and prevalence of thumb sucking for bite cluster (green indicating there is no history of thumb sucking and red indicating a history of thumb sucking).
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4.2 Factor analysis and eigenvalues highlighting four or perhaps five key variables.
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4.3 Scree plot with eigenvalue cut-offs suggesting four principle values for deeper exploration.
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4.4 The final architecture inclusive of eight variables and a binary outcome
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4.5 ROC plot with AUC of 0.86 68
4.6 Initial neural network architecture using only 2 inputs, 2 hidden layers of 2 and 1 nodes respectively, and a single binary output
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4.7 The logistic activation function defines the output of each node based on its input for a single probabilistic layer.
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4.8 Final neural network architecture using only 2 inputs, 2 hidden layers of 1 node respectively, and a single binary output
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X
LIST OF TABLES
1.1 Incidence of terminal molar relationships at three stages of occlusion development (Moyers, 1973, p. 135-137).
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4.1 Demographic characteristics of the sample population. 55
4.2 Descriptive Statistics Summary of the variables and occurrence frequency in the sample population.
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4.3 Statistical relationship between variables and the type of bite. 59
4.4 Neural analysis and rank of variables against the binary outcome. 66
4.5 Neural analysis and rank of variables against the binary outcome 69
4.6 Validation error tests for the final architecture 72
XI
LIST OF ABBREVIATIONS and ACRONYMS
< Less than
> More than
N Number
% Percentage
AFH Anterior Facial Height
AOB Anterior Open Bite
AUC Area Under Curve
CI Confidence Interval
CO Centric Occlusion
CR Centric Relation
EPI Epidemiological Information
ICP Intercuspation Position
JMP Statistical Analysis Program
NSW New South Wales
OMT Orofacial Myofunctional Therapy
OR Odds Ratio
OSA Obstructive Sleep Apnoea
PFH Posterior Facial Height
ROC Receiver Operating Characteristic
SD Standard Deviation
SDB Sleep Disordered Breathing
SPSS Statistical Package for Social Sciences
TAD’s Temporary Anchorage Device
TAFE Technical and Further Education
TMD’s Temporomandibular Disorders
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TMJ Temporomandibular Joint
VHA Vertical Holding Appliance
WHO World Health Organisation
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CHAPTER ONE
BACKGROUND
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1.1 INTRODUCTION
Anterior open bite (AOB) is a term used to describe the absence of an anterior
occlusion when all remaining teeth are in occlusion (Proffit, Fields Jr, & Sarver,
2014). It forms one of the main symptoms of an overall dentofacial deformity
(Figure 1.1) (Kim & Sung, 2018). AOB can be complex to diagnose, treat and
stabilise due to abundant interrelated aetiologic factors (Greenlee et al., 2011).
There are two categories that identify this malocclusion; dental/acquired open
bite and skeletal open bite with superimposed craniofacial dysplasia (Lin, Huang,
& Chen, 2013).
Figure 1.1: An illustration of facial and intra-oral photographs displaying the features of a patient with AOB (Kim & Sung, 2018, p. 284).
There is a discrepancy among how AOB has been defined in the literature and
this is reflected in the prevalence ranging between 2.0% and 46% (Peres, Barros,
Peres, & Victora, 2007; Sousa, Ribeiro, et al., 2014; Stahl, Grabowski, Gaebel, &
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Kundt, 2007; Ciuffolo, Manzoli, Attilio et al., 2005). Nonetheless, most
investigators concur that there needs to be lack of contact between anterior teeth
for it to be classified as an AOB (Cozza, Mucedero, Baccetti, & Franchi, 2005; G.
J. Huang, Justus, Kennedy, & Kokich, 1990; Shapiro, 2002). The variability in
incidence of this malocclusion is likely to reflect variations in age, socioeconomic
status, external environmental and other factors, and may be partly due to the
causative factors (Kharbanda, Sidhu, Shukla, & Sundaram, 1994; Kobayashi,
Scavone Jr, Ferreira, & Garib, 2010; Todor, Vaida, Csep, & Iurcov, 2015).
Non-nutritive sucking habits had been extensively reported in the literature and
was suggested to have an association with craniofacial deformities, mouth-
breathing and malocclusion (Gelgör, Karaman, & Ercan, 2007). It has been
reported that prolonged durations of non-nutritive sucking habits with tongue-
thrust tendencies formed a mechanical obstacle in the anterior teeth eruption
which led to development of malocclusions such as AOB (Helle & Haavikko,
1974; Katz, Rosenblatt, & Gondim, 2004; E. Larsson, 1985; Melsen, Stensgaard,
& Pedersen, 1979).
There are a number of other oral habits that influence development of
malocclusion, including digit and/or thumb sucking, tongue thrusting and forward
posture of tongue, pacifier use, and sucking other objects or toys (Cozza,
Baccetti, Franchi, Mucedero, & Polimeni, 2005; del Conte Zardetto, Rodrigues,
& Stefani, 2002; Góis et al., 2008; Helle & Haavikko, 1974). These habits link to
the age of the child, where it is postulated that as the child advances with age,
the prevalence of malocclusion decreases due to the cessation of non-nutritive
sucking behaviors (Vasconcelos et al., 2011). It is crucial that non-nutritive
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sucking habits cease at an early age to prevent craniofacial deformities and the
development of malocclusions such as AOB.
1.2 DENTAL OCCLUSION
Following an extensive journey throughout the history of dental practice and
science, occlusion has conquered its role as ‘the medium of dentistry’ (Ricketts,
1969). The study of dental occlusion has been a major subject of interest
throughout the advancement of dentistry (Angle, 1899; Okeson, 2014; Ramfjord
& Ash, 1966; Washburn, 1925). Assessment of occlusion, therefore forms a
clinically significant aspect of all dental disciplines (Gray, 2004).
Occlusion can be simply outlined as the contacts between teeth. Before
illustrating the significance of the various ways in which occlusal contacts are
made, the occlusion needs to be put into context. The masticatory
(stomatognathic) system is predominantly considered to be made up of three
units; the teeth, the periodontal tissues and the articulatory system (Davies &
Gray, 2001). The articulatory system is a congregation that is connected or
interdependent so as to shape a complex unit where the temporomandibular
joints act as hinges, the masticatory muscles as the motors and the dental
occlusion as the contacts (Davies & Gray, 2001).
In mechanical terms, it is evident that the elements of the articulatory system are
inevitably connected. Furthermore, it can be considered that they are obviously
interdependent because an alteration in any part will, therefore, affect the other
two parts, but this effect will not necessarily be adverse (Davies & Gray, 2001).
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1.2.1 Definitions and Classifications
The term ‘occlusion’ relates to the arrangement of maxillary and mandibular teeth
and the way in which the teeth make contact (Türp, Greene, & Strub, 2008). A
simplified definition of occlusion includes such phrases as the static relationship
(Aidsman, 1977) or any contact (McNeill, 1997) between the incising or
masticating surfaces of the maxillary and mandibular teeth or tooth analogues
(Aidsman, 1977). With epidemiological and clinical but not anthropological
focuses, this study adopted the definition of occlusion as “the static relationship
between the incising or masticating surfaces of the maxillary or mandibular teeth
or tooth analogues” (Ferro et al., 2005).
In a broader sense, the definition of occlusion is not restricted to morphological
tooth contact relationships, but rather encompasses the dynamic morphological
and functional relationships between all constituents of the masticatory system
(Davies & Gray, 2001). This includes teeth and their supporting tissues as well
as the neuromuscular system, temporomandibular joints (TMJs) and the
craniofacial skeleton (Klineberg & Jagger, 2004; McNeill, 1997; Mohl, 1988).
Angle’s classification of malocclusion in the 1890s was an important step in the
development of orthodontics because not only did it subdivide major types of
malocclusion but it also outlined the first clear and simple definition of normal
occlusion in the natural dentition. Angle’s claim was that the maxillary first molars
were the key to occlusion and that the maxillary and mandibular molars should
be related so that the mesiobuccal cusp of the maxillary molar occludes in the
buccal groove of the mandibular molar (Angle, 1900). If the teeth were arranged
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on a smoothly curving line of occlusion and this molar relationship existed, then
normal occlusion would result (Angle, 1900).
There are two sub-categories of occlusion; static and dynamic (Davies & Gray,
2001). The static occlusion refers to simply when teeth are in contact where the
mandible is closed and stationary, while dynamic occlusion refers to contacts
between teeth when the mandible is moving relative to the maxilla (Davies &
Gray, 2001). When taking into consideration a patient’s static occlusion it is
essential to identify if centric occlusion (CO) occurs in centric relation (CR)
(Davies & Gray, 2001). CO is defined as the occlusion the patient makes when
they fit their teeth together in maximum intercuspation or intercuspation position
(ICP); it is the occlusion that the patient nearly always makes when asked to close
their teeth together (Davies & Gray, 2001). CR is not an occlusion and has
nothing to do with teeth because it is only the ‘centric’ that is reproducible with or
without teeth present (Davies & Gray, 2001). CR is a jaw relationship; it describes
a conceptual relationship between the maxilla and mandible (Figure 1.2) (Davies
& Gray, 2001). CR is outlined in three ways; anatomically, conceptionally (Angle,
1899), and geometrically (Davies & Gray, 2001).
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Figure 1.2: An illustration of the temporomandibular joint showing the difference in mandibular position between a CO (solid line) and CR (broken line) (Shildkraut, Wood, & Hunter, 1994, p. 336).
Anatomical CR is illustrated as the position of the mandible to the maxilla, with
the intra-articular disc in position, when the condyle head is against the
uppermost part of the distal facing incline of the glenoid fossa (Figure 1.3).
Conceptual CR can be depicted as that position of the mandible relative to the
maxilla, with the articular disc in position, when the muscles that support the
mandible are at their most relaxed and least strained form (Davies & Gray, 2001;
Helland, 1980). This definition is applicable to the perception of ‘ideal occlusion’.
As for geometrical CR, it is defined as the position of the mandible relative to the
maxilla, with the intra-articular disc in place, when the condyle head is in terminal
hinge axis (Davies & Gray, 2001; Helland, 1980).
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Figure 1.3: Functional anatomy of the temporomandibular joint illustrating the position of the mandible to the maxilla with the intra-articular disc is in place (Helland, 1980, p. 147).
To understand this frequently used definition, it is simple to take into
consideration only one side of the mandible initially. The mandible first opens by
a rotation of the condyle and then a translation that is downwards and forwards
(Davies & Gray, 2001). Hence, when the mandible closes, the terminal closure is
essentially rotational (Davies & Gray, 2001). At this closure phase, the mandible
is implementing a simple arc as the centre of its rotation remains stationary, which
provides the ‘terminal hinge point’ of rotation of the one side of the mandible
(Davies & Gray, 2001). Due to the mandible structure being one bone with two
connected sides, these two terminal hinge points are linked by an imaginary line
known as the terminal hinge axis, which is visualised by imagining the stationary
centres of rotation of each condyle during movement of the mandible in the
rotational phase of movement (Davies & Gray, 2001).
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1.2.2 Structures Involved in Occlusion Development
To further expand on the extent of structures involved in the development of
occlusion, one needs to take into consideration the soft tissue anatomy and
function, airway function, size of the maxilla and mandible, tooth anatomy
(including malformation), arch form, congenitally missing teeth and rotation of all
teeth (Vu, Roberts, Hartsfield, & Ofner, 2008). All of these parameters need to
be incorporated in the notion of occlusion (Vu et al., 2008). On the other hand,
malocclusion is possibly simpler to define; where one can describe it as a
significant deviation from normal occlusion. Nevertheless, this definition is only
beneficial if one takes into consideration the multiple factors contained in such a
definition. Genetic influences, among many other causes, are suggested to have
a role on the dynamic concepts of the normal occlusion and malocclusion (Davies
& Gray, 2001).
Another factor that plays a role in manipulating the occlusion is known as
macroglossia, which refers to a larger than normal tongue size (Ayers & Hilton,
1976; Reynoso et al., 1993). Congenital macroglossia, which is caused by an
overdevelopment of the lingual musculature or vascular tissues, becomes more
apparent with growth of the child (Ayers & Hilton, 1976; Reynoso et al., 1993). A
tongue that is disproportionately large may lead to both an abnormal growth
pattern of the jaw and malocclusion (Ayers & Hilton, 1976; Reynoso et al., 1993).
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1.2.3 Development of Dental Occlusion
To simplify the occlusion and malocclusion dynamics further, good insight on the
growth and pattern of occlusion should be understood. The normal range of
overjet in the deciduous dentition ranges between 0 and 4 mm (Leighton, 1977).
One of the morphological differences between deciduous and permanent teeth is
the long axis of the tooth. Generally, overbite and overjet during the deciduous
stage of dentition do not undergo substantial changes unless they are influenced
by environmental factors including habits, dental caries and trauma (Dean, 2015).
The evidence that the width of the palate increases rapidly in the first six postnatal
months, is not necessarily conclusive of a change in the overjet, as the former
appears to play mediolaterally and the latter anteroposteriorly (Dean, 2015).
By three years of age, the occlusion of 20 primary (deciduous) teeth is generally
established. There are three categories that classify the relationship of the distal
terminal planes of opposing second primary molar teeth. A flush terminal plane,
or known as flush terminus is where the anterior-posterior positions of the distal
surfaces of opposing primary second molars are in the same vertical plane
(Leighton, 1977). A mesial step terminus is described as a mandibular second
primary molar terminal plane that is mesial to the maxillary primary terminus
(Leighton, 1977). In addition, distal-step terminal plane outlines the relationship
in which the mandibular second primary molar terminus is distal to the upper
second primary molar terminus. Statistical studies have shown that percentage
of prevalence of these terminal planes are 49% for mesial-step terminus, 37%
are flush-terminus and approximately 14% are distal-step primary terminus
(McDonald, Avery, Stookey, Chin, & Kowolik, 2011).
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Figure 1.4: Representation of occlusion development of the first molar with illustration of the terminal plane at approximately 5 years of age, and initial contact at approximately 6.5 years and final occlusion at about 12 years (Moyers, 1973, p. 135-137).
The first permanent teeth to develop and arise are the first permanent molars and
are clinically visible at approximately six years of age (Moyers, 1973). The
relationship of permanent first molars is illustrated by one of four categories when
initial occluding contacts occurs during eruption (Figure 1.4) and is classified in
classes (Moyers, 1973). The relationship where the mesial-buccal (m-b) cusp of
the upper first permanent molar contacts at or near the buccal groove of the lower
first permanent molar is known as a class I relationship and occurs in about 55%
of cases. An end on end relationship is where both m-b cusps of both molars
oppose one another and occurs in approximately 25%. A class II relationship is
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where the upper m-b cusp is anterior (in front of) to the lower m-b cusp, and
incidence is reported in 19% of cases. Class III relationship, occurring 1% of the
population, is where the upper m-b cusp positioned posterior (behind of) to the
lower buccal groove (Carlsen & Meredith, 1960).
Table 1.1: Incidence of terminal molar relationships at three stages of occlusion development (Moyers, 1973, p. 135-137).
Primary terminal place (Age 5 years)
Initial permanent first molar occlusion (6.5 years)
Final occlusion (approx. 12 years)
1% Class III 3% Class III
49% Class I (ms) 27% Class I 59% Class I
37% Flush 49% End-on 39% Class II
14% Class II (ds) 23% Class II
The notion of ideal occlusion development had been explained by Friel (1927),
and by Lewis and Lehman (1929). In addition, Sanin and Savara (1972) had also
outlined that ideal occlusion at a young age predisposes to an ideal occlusion in
adulthood. The occlusion that’s most desirable is a class I ICP, and several
features in the primary dentition, when accurately detected, can establish clinical
signs as to whether a class I relationship of the dentition will ultimately take place.
Foreseeing subsequent arch relationships cannot be utilised as a consistent
diagnostic standard through gum pad relationships due to the dominance of
respiratory and swallowing functions, which are great at birth and hence
unpredictable adjustments in maxillary and mandibular positions occur in first few
years of life (Sanin & Savara, 1972). At three years of age, there is establishment
of the maxilla and mandible relationship with the overall maxilla-mandibular
pattern does not alter substantially thereafter (Sanin & Savara, 1972).
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One major diagnostic characteristic regarding future occlusion status is the
relationship of the primary terminal planes. The prospect of a class I relationship
developing in the permanent dentition is utmost when a mild mesial-step terminus
exists during the primary dentition stage (Figure 1.4) (Moyers, 1973). A class III
permanent molar relationship will form if there is an exaggerated mesial step in
the primary molars. The likelihood that a class I relationship developing from a
distal-step primary terminus is practically non-existent (Moyers, 1973). The
presence of a distal step is therefore largely prognostic of a developing class II
permanent molar relationship.
On the other hand, another significant diagnostic trait that is prophetic of later
occlusion status is the relationships of the first permanent molars during initial
occluding contact. These erupt at approximately six years of age and the chance
that a class I ICP of the dentition will develop is greatest when a class I
relationship is observed at initial permanent first molar occluding contact (Moyers,
1973). It can be said that occlusion relationship of upper to lower dentition
persists nearly the same throughout the growth period (da Silva & Gleiser, 2008).
Other factors can contribute to this and allow for exceptions. These factors
include environmental, premature loss of primary teeth and congenitally missing
teeth (Northway, Wainright, & Demirjian, 1984).
The developments of dental arch malocclusion or clinically acceptable dental
arches are predictable. The condition of the dental arch at mid-adolescence is
reliant on clinical characteristics that can be simply predicted during the transition
phase dentition (Moyers, 1973). A straightforward technique of evaluating the
dental arch for traits that predispose to malocclusion is to compare the patient’s
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mixed dentition dental arch with an ideal dental arch pattern. For a seven year
old child, the ideal dental arch pattern should have no rotations, be in tight
proximal contacts, possess specific buccal-lingual axial inclinations and specific
mesial-distal axial inclinations, have even marginal ridges vertically, flat occlusal
plane and excess (positive) leeway space (Anderson, 2007).
Wassell et al., (2008) suggests that the concept of a morphologically correct or
incorrect ICP does not exist. Wassell et al., (2008) further mentions that all of the
orthodontic “classes” are common, including class I relationships being rarely
perfect. There are many normal variations which are consistent with satisfactory
function and oral health (Wassell et al., 2008).
The positions and shapes of teeth define the ICP. In most people, the cusps of
the posterior teeth in one arch fit into the fossae and onto marginal ridges on the
opposing arch in a unique way, just as key fits a lock, providing an ICP that is
highly reproducible and stable (Wassell et al., 2008). A minority of people are
unable to find a single position due to their teeth arrangement and therefore do
not possess a stable ICP (Wassell et al., 2008). The axial inclination is not taken
into consideration to define the “ideal” occlusion. For the majority of people, when
they close their teeth together they always and smoothly end up n ICP (Wassell
et al., 2008). It is further illustrated that the ICP is only consistent and stable when
there are enough teeth in order to define it (Wassell et al., 2008).
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1.3 MALOCCLUSION
1.3.1 Anterior Open Bite (AOB)
Open-bite relationships are characterized by lack of the teeth in both arches to
contact properly (Figure 1.5) (Cangialosi, 1984). Open bites can be detected in
the anterior or posterior region and may be attributable to supra-eruption of the
adjacent teeth or infra-eruption of the teeth in the area of question. Open bites
can be outcomes of abnormal habits, deviant growth patterns, or an abnormal
tongue position.
Diagnosis of open bites should be viewed first in the context of skeletal structures.
Sassouni (1969) classified open bites into skeletal and dental open bites. The
latter have no significant skeletal abnormality. When the skeletal morphology in
the vertical dimension has been classified successfully, it can be determined
whether or not a dental open bite accompanies the skeletal relationships. Figure
1.6 (Ngan & Henry, 1997) shows that there are multiple variants of this problem.
16
Figure 1.5: Representation of an open-bite pattern using a cephalometric tracing of landmarks and planes (Cangialosi, 1984, p. 30).
Involving AOB, it must be decided whether the open bite is a true skeletal
dysplasia or a habitual problem involving only the dentoalveolar structures. In
addition, any means of identifying the skeletal pattern of an open bite may be
helpful in the possible prevention or early treatment of this condition and also be
a guide in assuring that the mechanics employed will not aggravate the condition.
Many studies have been carried out yielding extensive information regarding the
morphologic characteristics and specific areas of this dysplasia (Cangialosi,
1984).
17
Figure 1.6: This diagnostic flow chart demonstrates the possibilities and relationships between skeletal and dental relationships in open bite malocclusion (Ngan & Henry, 1997, p. 91-98).
1.3.1.1 Prevalence of AOB
In the deciduous dentition, prevalence of malocclusions may be divided into four
major categories: deviations in available space, deviations in the vertical plane,
deviations in the sagittal plane, and deviations in the transversal plane (Koch &
Poulsen, 2009). In the primary teeth, space conditions possess a different
meaning than in the permanent teeth (Table 1.1).
In the deciduous dentition, spacing between the anterior teeth is a normal
anatomical characteristic, while small spaces or crowding in the deciduous front
teeth indicate that this may proceed into the permanent dentition as well. The
18
permanent central incisors will likely resorb both central and lateral primary
incisors during eruption, shifting the lack of space distally in the dental arch. This
lack of space should not be treated in the primary dentition, but closely monitoring
the eruption of the permanent successors is necessary (Koch & Poulsen, 2009).
Vertical plane malocclusions (Table 1.1) do not represent to be problematic in the
deciduous dentition.
Open bite descriptions vary among different authors and researchers. Several
orthodontic specialists define an open bite to be present when there is less than
an average overbite, while others believe an edge-to-edge relationship between
anterior teeth to be an open bite (Subtelny & Sakuda, 1964). In addition, many
researchers have postulated that a certain degree of openness must be present
to classify as an open bite (Subtelny & Sakuda, 1964). Due to varying definitions
of open bite, the occurrence of reported cases vary also and in turn altering
statistics representing the frequency with encountered cases of this abnormal
dental occlusion in the orthodontic practices (Subtelny & Sakuda, 1964).
The prevalence of AOB is high, but is almost always dentoalveolar and most likely
due to sucking habits. AOB closes in most cases when sucking habits diminish
(Moss & Salentijn, 1971). Studies report the range of prevalence for AOB to be
from 6% to 50% for AOB (Akbari et al., 2016; Alonso Chevitarese, Valle, &
Moreira, 2003; Carvalho et al., 2011; Ciuffolo et al., 2005; Corrêa-Faria, Ramos-
Jorge, Martins-Júnior, Vieira-Andrade, & Marques, 2014; Paola Cozza, Manuela
Mucedero, et al., 2005; Dos Santos et al., 2012; Gelgör et al., 2007; Macena,
Katz, & Rosenblatt, 2009; Moss & Salentijn, 1971; Parker, 1971; Sousa, Ribeiro,
19
et al., 2014; Stahl et al., 2007; Urzal, Braga, & Ferreira, 2013; Zuroff et al.,
2010).
This variance is possibly due to different cultural and economic standards
internationally, which may impact on the habits and behaviours of their respective
population (Corrêa-Faria et al., 2014; Sousa, Pinto-Monteiro, Martins, Granville-
Garcia, & Paiva, 2014; Sousa, Ribeiro, et al., 2014). Factors such as ethnicity,
socioeconomic background, environmental influences, and age can impact on
the prevalence. Furthermore, the prevalence differs substantially among studies
depending on how authors describe this abnormal occlusion. Another impact of
low socioeconomic status to take into consideration was accessibility and
affordability of preventative or treatment methods to manage malocclusions such
as AOB.
According to the findings by Ng, Wong, & Hagg (2008), they noted that sucking
habits tend to diminish while oral function matures with age, while individuals from
low socioeconomic backgrounds tend to develop this malocclusion more so due
to mothers needing to work full-time and are unable to provide breastfeeding for
the advised duration. There is, however, no supporting evidence in other studies
to suggest that mothers of only low socioeconomic backgrounds needing to work
and therefore, did not breastfeed for the recommended duration.
The primary dentition stage is the utmost ideal phase for preventive and
interceptive measures (Kobayashi et al., 2010). Gender did not have any impact
on AOB (Machado et al., 2014; Peres, Barros, et al., 2007; Sousa, Lima,
Florêncio Filho, Lima, & Diógenes, 2007), while school type was closely linked,
20
showing those who attended public schools were more likely to develop AOB
than private schools ( Sousa, Pinto-Monteiro, et al., 2014).
1.3.1.2 Development of AOB
The primary dentition role in the formation of permanent occlusion is well
recognised. The substance of primary teeth as “space maintainers” for the
permanent teeth is distinct, particularly following early loss of the primary second
molars due to caries or ectopic eruption of the first permanent first molars.
Nevertheless, the deciduous dentition also acquires its own malocclusions,
which, if untreated, may be transmitted to the permanent dentition (Cameron &
Widmer, 2013). Several of the malocclusions, in particular anterior and posterior
functional cross bites and scissor bites, have the additional disadvantages that
may influence facial growth and development of the occlusion when untreated
(Cameron & Widmer, 2013).
The open bite must be evaluated as a deviation in the vertical relationship of the
maxillary (upper) and mandibular (lower) dental arches. There should therefore
be a certain lack of contact, in the vertical direction, between opposing segments
of teeth. The degree of openness may differ from patient to patient but an edge-
to-edge relationship or some form of an overbite cannot be technically classified
as an open bite (Subtelny & Sakuda, 1964).
Dental open bites are attributed to the unfavourable behavioural habits involving
digit sucking, pacifier use and forward posture of tongue (English, 2002). This
can lead to an under eruption caused by an obstruction prevention the eruption
of the incisor teeth, removing the unfavourable habit will essentially lead to self-
21
correction of the open bite (English, 2002). While, skeletal open bite generally
displays super eruption of the maxillary teeth with an increase in dentoalveolar
heights (English, 2002). A study by Cangialosi (1984) demonstrated that skeletal
open bites display more eruption of molars and incisors in comparison to dental
open bite.
1.3.1.3 Aetiology of AOB
There are several proposed aetiologic factors linked with open bite;
1. Vertical growth deficiencies, these are usually outlined despite varying
beliefs of locating exact area suggesting this deficiency (Subtelny &
Sakuda, 1964). Most authors suggest that the vertical deficiency is located
in the anterior portion of the maxilla (Ackerman & Proffit, 1969; Bergersen,
1988; Samir E Bishara & Jakobsen, 1998; Paola Cozza, Tiziano Baccetti,
Lorenzo Franchi, Manuela Mucedero, & Antonella Polimeni, 2005),
2. Disproportionate muscle growth or abnormal muscle function with an
enlarged, extremely fronted or protrusive tongue function is believed to
inhibit complete eruption of anterior dental units or apply a disfiguring
influence on the sculpting of the anterior denotalveolar processes
(Subtelny & Sakuda, 1964), and
3. Oral habits such as thumb or digit sucking can also play a role (Subtelny
& Sakuda, 1964). If these aetiologic factors are taken into consideration
within the fundamental orthodontic principles, it is not mistaken to suggest
that there seldom will be one single aetiologic factor (Subtelny & Sakuda,
1964).
22
1.3.1.3.1 Skeletal
In a study conducted by Hellman (1931), involving 43 patients with AOB identified
that the treated group of patients displayed equivalent percentage of success to
those who had spontaneous self-corrections in the untreated group. Based on
these observations, he proposed that the skeletal growth deficiencies were the
primary cause of open bite. On the other hand, other authors have suggested
that the main cause of open bite to be due to tongue thrusting (Straub, 1960;
Swinehart, 1942). They have also suggested that this open bite can be corrected
through retraining the tongue and eliminating muscle dysfunction. In contrast,
Subtelny (1973) stated that muscular activity during deglutition is primarily
determined by form. This means that the reason the tongue is thrust forward is
so that it acts as an oral seal which is necessary for deglutition. Hence, Subtelny
(1973) suggested that it is questionable whether the tongue causes this open bite
or acts in reverse.
Furthermore, growth factors and age also play vital roles in the AOB. Worms,
Meskin, and Isaacson (1971) conducted a study involving 1,408 Native American
children. They identified that there was a spontaneous correction of AOB’s in 80%
of the sample as children grow from seven to nine year age group. In addition,
other studies have suggested the tongue to play a major role in swallowing up to
the age of 10 years (Fletcher, Casteel, & Bradley, 1961; Ward, Malone, Jann, &
Jann, 1961). Following this age, this mode of swallowing is decreased remarkably
which aids in the spontaneous correction of AOB (Fletcher et al., 1961; Ward et
al., 1961).
23
In summary, the skeletal open bite is often due to the excessive vertical growth
of the dento-alveolar complex, in particular in the posterior molar region. AOB is
usually caused by a combination of both dental and skeletal factors, it is difficult
to classify it as either skeletal or dental. Aetiology of AOB is caused by a
combination of genetic, anatomic and environmental factors (Lin et al., 2013).
1.3.1.3.2 Oral Habits
Oral habits that affect the dental occlusion include non-nutritive sucking
behaviours such as using a pacifier or finger/thumb sucking. Digit sucking can
develop an asymmetrical AOB which is more pronounced on the side the digit is
being sucked on (Lin et al., 2013). It is duration and frequency of digit sucking is
what leads to AOB.
It has been suggested that six hours or more of daily digit sucking can lead to
malocclusion (Lin et al., 2013). Furthermore, it has been noted that thumb-
sucking behaviours are considered normal in a child that is under the age of three
years (Warren & Bishara, 2002). Prolonged habits of thumb and/or finger sucking
with or without tongue thrusting tendencies can result in obstructing proper
eruption of permanent anterior teeth (Warren & Bishara, 2002).
Some even suggest that oral habits can lead to protrusion of the upper anterior
teeth, leading to lack of contact and thus being classified as an AOB as a result
(Bishara, Warren, Broffitt, & Levy, 2006). Another study found that oral habits
were highly linked to the development of malocclusions such as posterior cross-
bites (Facciolli Hebling et al., 2008; Macena et al., 2009; Scavone-Junior,
Ferreira, Mendes, & Ferreira, 2007). There seems to be an agreement in the
24
literature in that cessation of the unfavourable oral habits such as sucking on
pacifiers, fingers or thumb can lead to self-correction of the AOB (Cardoso, Bello,
Vellini-Ferreira, & Ferreira-Santos, 2014).
1.3.1.3.3 Other Aetiological Factors
There has been an agreement among numerous authors to suggest that non-
nutritive sucking habits as being the consequences of modernization and
industrialization, where more women worked and thus undertaken shorter breast-
feeding periods, favoring the adoption of non-nutritive sucking behaviors
(Vasconcelos et al., 2011). This led to development of AOB malocclusion.
Furthermore, some authors had proposed that AOB is influenced by factors such
as age, ethnicity and dentition (Ciuffolo et al., 2005; del Valle, Dave-Singh,
Feliciano, & Machuca, 2006; Øgaard, Larsson, & Lindsten, 1994; Peres, De
Oliveira Latorre, et al., 2007).
1.3.1.4 Treatment of Anterior Open Bite
Environmental and/or genetic factors may lead malocclusions to develop and a
large number of malocclusions will persist in the permanent dentition, unless they
are treated. Oral habits, reduced activity in jaw muscles, hypertrophic tonsils and
adenoids, dental trauma, early loss of deciduous teeth, and severe chronic
disease in childhood are all categorised under the environmental factors
(Cangialosi, 1984).
During childhood, there is an inconsistency between tongue volume and available
space in the oral cavity. In addition, adenoids are often large in size. Through
reduction of adenoids size and increased oral space during growth, a large
25
number of these AOB’s spontaneously close. While skeletal open bite may be the
result of a posterior rotation of the mandible during growth (Cangialosi, 1984).
AOB treatment is complex in orthodontics. There are several approaches in
treating this malocclusion used in current orthodontic practices. It has been
suggested to be favourable that patients cease oral habits such as thumb/finger
sucking before commencement of orthodontic treatment (Dellinger, 1986; Ngan
& Fields, 1996). While orthognathic surgery is indicated in non-growing patients
with a skeletal AOB. The aim of utilising orthognathic surgery is to reduce the
vertical skeletal growth with intra-oral and extra-oral forces (Dellinger, 1986; Ngan
& Fields, 1996). For the growing patients, few techniques have been suggested
to maintain vertical growth, including vertical holding appliance (VHA), posterior
bite blocks and functional appliances such as activators, bionators and Fränkel
regulators (Dellinger, 1986; Ngan & Fields, 1996).
In adult patients, orthognathic surgery is often indicated for significant open bites
and aesthetic needs. Surgeries involve both the maxilla and mandible, anterior
maxillary and mandibular surgeries as well as combine surgeries of mandible and
temporary anchorage devices (TADs) (Bell & Dann, 1973; Brammer et al., 1980;
Hiranaka & Kelly, 1986; Taylor, Mills, & Brenner, 1967; Togawa, Iino, & Miyawaki,
2010).
Other mechanisms that correct functional habits include the prevention of the
tongue to rest on the anterior teeth ( Haryett, Hansen, Davidson, & Sandilands,
1967). These are best identified as lingual or palatal cribs (Subtelny & Sakuda,
1964) and spurs (Justus, 2001; Meyer-Marcotty, Hartmann, & Stellzig-
26
Eisenhauer, 2007). There is an agreement until automatic movements are
established, these devices should be fixed to re-educate the oral function (Meyer-
Marcotty et al., 2007; Nogueira, Mota, Nouer, & Nouer, 2005b). The palatal or
lingual cribs are designed to prevent the tongue from resting on the teeth and in
turn correcting the AOB (Subtelny & Sakuda, 1964).
These structures are smooth and purposefully enable the tongue to rest on them
so that in several cases it may block the functional re-education of the tongue.
Hence the tongue then returns to its original position resulting in relapse of AOB
(Rogers, 1927). While spurs stimulate a change in the tongue resting position,
hence enabling tooth eruption and closure of the open bite. This change of tongue
position modifies sensory perception by the brain, thus creating a new motor
response which can be permanently imprinted by the brain (Justus, 2001; Meyer-
Marcotty et al., 2007). This clarifies the permanent change in tongue posture
created by spurs and resulting in AOB treatment stability (Justus, 2001; Meyer-
Marcotty et al., 2007).
Other treatments include behavioural modifications to eradicate oral habits or
abnormal functions. Orofacial myofunctional therapy (OMT) is utilised to modify
function and is composed of a set of exercises that re-educate orofacial muscles
in swallowing, speech and resting posture (Franco, Araújo, & Habib, 2001; Miller,
1969; Subtelny & Sakuda, 1964). These are generally combined with orthodontic
treatment that involves extruding the anterior teeth or intruding the molars, and
surgical treatment of the basal bones (Greenlee et al., 2011). The only
agreement that seems to be established is that treatment of the AOB is
27
demanding and has poor stability (Denison, Kokich, & Shapiro, 1989; Huang et
al., 1990; Lopez-Gavito, Wallen, Little, & Joondeph, 1985; Zuroff et al., 2010).
1.3.2 Other Malocclusions
There are wide variations of the epidemiological data on malocclusion. This is
partly due to the population being screened, and partly on the method of
recording these malocclusions (Tschill, Bacon, & Sonko, 1997). Tooth to jaw
divergence is one of the most common features seen in modern society. The
genetic factors as well increased outbreeding have been suggested to have
impact on the prevalence of crowding in the dentition in today’s populations
(Tschill et al., 1997).
Numerous studies have been published on the prevalence of malocclusions in
various populations. The reported incidence is suggested to range from 39% to
93% (Johannsdottir, Wisth, & Magnusson, 1997; Kerosuo, Laine, Nyyssonen, &
Honkala, 1991; Otuyemi & Abidoye, 1993; Tschill et al., 1997), identifying that the
majority of children have irregular teeth alignment and occlusal relationships that
diverge from the ideal. It is noted that ethnic groups, different demographics as
well as difference in the recording criteria are the most important factors outlining
these differences in incidence rates.
It is noted that the prevalence of crowding in Caucasian populations to be at its
highest levels later in life (Helm, 1968; Infante, 1976; Thilander & Myrberg, 1973).
Individuals who display contact between their maxillary primary teeth are more
likely to develop crowding in the permanent dentition (Helm, 1968; Infante, 1976;
Thilander & Myrberg, 1973). Leeway space as well as surface remodelling that
28
accompanies the eruption of the maxillary permanent central incisors may result
in development of space conditions that prevents crowding from taking place
(Tschill et al., 1997).
A study by Tschill et al. (1997) examining malocclusion of children aged four to
six years found that a normal protrusion of the maxillary incisors (overjet of 1-
3mm) accounted for 76% of their studied population, while an excessive overjet
(6mm or more) was found in only 3.7% of the same studied population. The same
conditions were noted in a Finnish study of children aged three years, which
found 2.1% of the population to have an excessive overjet of 6mm or greater
(Järvinen & Lehtinen, 1977). It is suggested that the frequency of excessive
overjet for the deciduous dentition is an inaccurate replication of conditions
accompanying the permanent dentition, where it is expected that prevalence of
malocclusions such as excessive overjet to increase with maturation (Tschill et
al., 1997).
There were no differences noted on the prevalence of Angle Classes II and III in
Europeans and white Americans (Thilander, Pena, Infante, Parada, & de
Mayorga, 2001). The noted difference, however, was between the developmental
stages where there was a decreased prevalence of Class II, but increased
prevalence of Class III, from the late mixed to the permanent dentition (Thilander
et al., 2001). This is possibly due to a growth spurt in the mandible. The reported
prevalence of class III malocclusion was estimated to be 3.7% with an increase
in prevalence with ageing (Thilander et al., 2001). While class II occlusions (i.e.
deep bite) had a reported prevalence of 19% to 36% (Foster & Hamilton, 1969;
Humphreys, 1950; Infante, 1975; Ravn, 1975; Tschill et al., 1997).
29
1.4 FACTORS AFFECTING MALOCCLUSION
Medical studies have outlined the significance of innate psychological attributes
such as self-esteem and its role in predicting the effect of health conditions on
the quality of life (Foltz, 1987; Katz, Rodin, & Devins, 1995). There are several
studies that have examined the associations between self-esteem, effects on
quality of life and dental occlusion. A Brazilian study of school children identified
that children from lower socioeconomic backgrounds were more aware and
sensitive to the aesthetic impacts of their malocclusion (Marques, Barbosa,
Ramos-Jorge, Pordeus, & Paiva, 2005). In another study in Nigeria, similar
findings were reported in that children from higher socioeconomic backgrounds
did not express concerns regarding their malocclusion ( Onyeaso, 2003).
Furthermore, socioeconomic inequalities remains to be a challenge in both
developed and underdeveloped countries (Cardak & Ryan, 2006; Marks,
Cresswell, & Ainley, 2006). In Australia, there is significant under-representation
of people from low socioeconomic backgrounds in higher education (James,
2000; McMillan & Western, 2000). Moreover, one of the most crucial issues of
health in the Australian population is the large geographical area and the
population dispersal. The high cost of dental treatment and lack of services
available is seen in numerous regional, rural and remote locations in Australia
(Steele, Pacza, & Tennant, 2000).
It is also suggested that individuals residing in communities where the closest
public health clinics to be more than 200km away were those from lower
socioeconomic backgrounds and at higher risk for health issues, including oral
30
health (Perera, Kruger, & Tennant, 2010). Hence individuals with limited
disposable incomes and geographic location are disadvantaged from regular
access to healthcare. The majority of dental practitioners reside in urban
communities, with fewer numbers seen in regional, rural and remote locations
(Steele et al., 2000). This thus leads to increased dental care costs as well as
lack of proper access respective of the population need in the regional, rural and
remote communities.
The sample population chosen for this study is from Orange, a regional town in
New South Wales, located in the central west of the state, a diverse community
of people with high socioeconomic status and people with low socioeconomic
status. The regional town has a dental school as well as private and public dental
services.
31
CHAPTER TWO
LITERATURE REVIEW
32
2.1 OPEN BITE MALOCCLUSION
For over a century, issues relating to dental occlusion have been widespread
controversies. Such controversies have impacted on the health of the oral cavity
at varying degrees, commencing with orthodontic matters during childhood and
proceeding to occlusal evaluations of adult patients in general dental practice.
Furthermore, the necessity to carry out complex restorative dentistry demands
critical thinking to establish optimum results.
Restorative dentistry is the restoration of a tooth to or close to its original form by
means of metallic, porcelain, synthetic, resin or inlay materials. In addition,
patients whose masticatory system has developed pain and dysfunction
(temporomandibular disorders, TMDs), there seems to be a high likelihood that
their problems would be assessed and managed with some occlusal concept
(Türp, Greene, & Strub, 2008).
On the other hand, the dental open bite is generally accompanied by normal
craniofacial configurations, with incisors that are proclined (protruding forward)
and under-erupted anterior teeth as well as a normal molar height with thumb-
sucking or other oral habits (Beane, 1999). The majority of open bites contain
both dental and skeletal characteristics (Beane, 1999). While dental open bites
can be treated with orthodontic or behaviour shaping strategies, the skeletal open
bite requires a more complex approach combining orthodontic and orthognathic
surgical procedures to reach function, aesthetics and stability (Frost, Fonseca,
Turvey, & Hall, 1980; Lawry, Heggie, Crawford, & Ruljancich, 1990).
33
Figure 2.1: Comparison between ideal class I anterior occlusion (A) and anterior open bite malocclusion (B) (Ackerman & Proffit, 1969, p. 445).
Figure 2.2: An illustration of AFH: Anterior facial height, and PFH: Posterior facial height, the objective of treatment is to maintain AFH and to improve PFH (Horn, 1992, p. 181).
34
2.1.1 Prevalence of AOB
Given the above definitions, the prevalence of AOB differs substantially among
studies depending on how authors describe this abnormal occlusion. The word
‘malocclusion’ can be subjective, as the notion of ‘ideal’ occlusion is a rare
incident and hence slight occlusal variations do not necessarily lead to specific
health risks. Having said that, the AOB is described as abnormal as it impacts on
the patient’s function, speech, mastication, future dental health risks and
aesthetics (Mohlin & Kurol, 2002). Reported prevalence in the population is
estimated to range from 2% to 46% (Akbari et al., 2016; Alonso Chevitarese et
al., 2003; Carvalho et al., 2011; Ciuffolo et al., 2005; Corrêa-Faria et al., 2014;
Cozza, Mucedero, et al., 2005; Dos Santos et al., 2012; Gelgör et al., 2007;
Grabowski, Stahl, Gaebel, & Kundt, 2007; Macena et al., 2009; Moss & Salentijn,
1971; Parker, 1971; Sousa, Ribeiro, et al., 2014; Stahl et al., 2007; Urzal et al.,
2013; Zuroff et al., 2010).
Numerous factors affect the open bite, including age, gender, non-nutritive
sucking habits, to mention a few. Factors such as age can impact on prevalence,
as sucking habits and oral function mature with age. At the age of six, the AOB
presents as low as 4.2%, while at age 14 years the prevalence declines to 2%
(Cozza, Mucedero, et al., 2005). In the American population, the prevalence
detected was ethnicity-dependent with 3.5% present in Caucasian children while
16.5% in Afro-descendent children (Zuroff et al., 2010). Although the prevalence
is low, the necessity to treat this malocclusion is very common with around 17%
of orthodontic cases having AOB (Zuroff et al., 2010). Another study found that
prevalence of AOB to be 21% in children aged three to five years (Sousa, Ribeiro,
et al., 2014).
35
There are many factors that can influence the discrepancy in the prevalence
(Heimer, Tornisiello Katz, & Rosenblatt, 2008; Macena et al., 2009). Varying
cultural and economic standards, socioeconomic backgrounds, ethnicity, age,
location and other social demographics and environmental influences all
contribute to the alteration of the reported prevalence in the population (Machado
et al., 2014; Øgaard et al., 1994; Sousa, Ribeiro, et al., 2014).
2.1.2 Prevalence of Non-Nutritive Sucking Habits
Sucking behaviours among infants and young children primarily originate from
the physiological need for nutrients. The current understanding of child
development also suggest that the sucking behaviours also develop from the
psychological needs. Infants possess the natural biological drive for sucking
(Johnson & Larson, 1993). This sucking urge can be satiated through nutritive
sucking (breastfeeding and/or bottle-feeding), as well as non-nutritive sucking
(finger/thumb-sucking, pacifier use, or toys). These behaviours are considered
normal in infants and young children, however persisting behaviour for a long
duration may impact on the developing orofacial structures and occlusion (Adair,
Milano, Lorenzo, & Russell, 1995; Larsson, 1983; Lindner & modѐer, 1989;
McRae, 2010; Øgaard et al., 1994; Ravn, 1976).
An early Swedish study on prevalence of non-nutritive sucking habits found a
pacifier sucking prevalence to be 12%, while digit sucking prevalence to be 50%.
Higher proportions of thumb-sucking habits were reported from other locations
with either little or no pacifier use (De Boer, 1976). Over the decades, these
36
trends have dramatically changed, and prevalence of pacifier use up to 70% has
been more commonly evident (Larsson & Dahlin, 1985; Ravn, 1974).
A Danish study on non-nutritive sucking habits prevalence found that from 70%
to 90% of Danish children had history of some form of non-nutritive sucking
behaviours. (Ravn, 1974). Another study by Svedmyr (1979) involving three to
five year old Swedish children, found that only 14% of children had non-nutritive
sucking habits. Out of the 14%, 62% had history of pacifier use. While another
Swedish study noted the prevalence of non-nutritive sucking habits of four year
old children was 88%, with 48% continuing this habit at the age of four, but also
found the majority or participants had pacifier use habits, accounting for 78% of
those with habits (Modёer, Odenrtck, & Lindner, 1982). This study is in agreement
with the Danish study in the extent of prevalence in the studied population, but in
agreement with the earlier Swedish study on the pacifier use predominance of
non-nutritive sucking habit.
There is an equal distribution of non-nutritive sucking prevalence among boys
and girls. It has also been noted that when infants initially develop the pacifier
sucking habits, its intensity is generally low in the first few weeks (Larsson, 1983;
Larsson & Dahlin, 1985). And most children tend to cease the pacifier habits at
age two to three years. In a retrospective study involving 920 Swedish children
aged nine years, Larsson (1986) reported that 351 out of the 412 (85%) children
who displayed pacifier sucking habits had ceased prior to turning four years. After
six years of age, 11 (3%) were still using pacifiers, and, at age nine, only one girl
still continued the habit (Larsson, 1986).
37
In recent societies, literature reported between 10% and 34% of children carry
out thumb/finger sucking during their first year of life (Bishara et al., 2006;
Cardoso et al., 2014; Franco & Gorritxo, 2012; Heimer et al., 2008). While in more
traditional societies, digit/thumb-sucking habits are not commonly present. There
are comparatively very few studies carried out in the United States on prevalence
of non-nutritive sucking habits. Infante (1976) investigated children aged two to
five years and found that 19% had active finger/thumb-sucking habits, with a
higher proportion being girls displaying this habit. While pacifier use was not
recorded, it was suggested that the majority of these children used pacifiers (
Infante, 1976).
2.1.3 Correlations of AOB and Determinant Factors
Several aetiologic factors linked with open bite have been proposed. These
include genetic, anatomic and environmental factors. When taking the genetic
factors into consideration, the open bite is mainly associated with patients’
unfavourable growth capacity and heredity (Björk, 1969; Sassouni, 1969;
Subtelny & Sakuda, 1964). A detailed family history as well as radiographic and
cephalometric analyses are hence necessary to identify whether there is a
genetic factor present (Ellis & McNamara, 1984).
The anatomic factor includes size and position of the tongue has been suggested
to affect both the dental and skeletal factors (Kawakami, Yamamoto, Noshi,
Miyawaki, & Kirita, 2004). Furthermore, macroglossia, which is an unusually
enlarged tongue, has also been proposed to influence AOB (Miyawaki, Oya,
Noguchi, & Takano-Yamamoto, 2000). Reports identify that in individuals with
AOB, a strong relationship between the angle of the mandible plane, mandibular
38
ramus height, or the maxillary anteroposterior dimension and front section of the
dorsal surface of the tongue movement during swallowing (Fujiki et al., 2004).
In addition, several anatomic ailments including enlarged tonsils and/or
adenoids, swollen nasal turbinates and nasal septums that are deviated may
impact on normal upper respiratory nasal function (Watson, 1981). Consequently,
due to upper airway obstruction, mouth-breathing can take place and, in turn lead
to AOB; however, a direct link has not yet been proven (Vaden & Pearson, 2002).
In contrast, environmental factors such as thumb and finger sucking, forward
posture of tongue and tongue thrust have all been suggested to cause AOB
(Popovich & Thompson, 1973; Straub, 1960, 1961, 1962). Digit sucking had been
said to cause an asymmetrical AOB that is worst on the side where the digit
sucking takes place. Having said that, not all thumb or finger suckers acquire an
AOB; this is more dependent on frequency and duration of the habit (Lin et al.,
2013).
Earlier studies suggests a relationship between non-nutritive sucking habits and
occlusal abnormalities, particularly AOB, increased overjet (protrusion) and
Angle’s class II canine and molar relationship (E. Larsson, 1978). Furthermore, it
has been reported that those who suck for duration of six hours or longer a day
leads to considerable malocclusions (Lin et al., 2013; Popovich & Thompson,
1973). A forward tongue posture, which describes the state where the tongue
rests between the incisors may lead to obstruction of incisor eruption can cause
AOB (Lin et al., 2013; Straub, 1960, 1961). In addition, tongue thrust, whereby
39
the tongue moves forward during deglutition can also lead to AOB (Lin et al.,
2013; Straub, 1962).
2.1.4 Treatment Options
Due to the above mentioned etiologic factors, several treatment options have
been proposed for treatment and/or management of the AOB malocclusion. The
treatment options include behavioural modifications to eradicate oral habits or
abnormal functions and re-educate oral muscles during swallowing and
deglutition (Barbre & Sinclair, 1991; Benkert, 1996; Huang et al., 2015; Huang et
al., 1990; Ngan & Fields, 1996; Smithpeter & Covell, 2010; Van Dyck et al., 2016),
orthodontic treatment that involves extruding the anterior teeth or intruding the
molars (Bondemark et al., 2007; Cooke, 1980; Epker & Fish, 1977; Haralabakis
& Papadakis, 2005; Ng et al., 2008; Swinnen et al., 2001), and surgical treatment
of the basal bones (Epker & Fish, 1977; Greenlee et al., 2011; Haralabakis &
Papadakis, 2005; Haymond, Stoelinga, Blijdorp, Leenen, & Merkens, 1991;
Swinnen et al., 2001). The only agreement that seems to be current is that
treatment of the AOB is demanding and has high rates of relapse (Denison et al.,
1989; Huang et al., 1990; Lopez-Gavito et al., 1985; Zuroff et al., 2010).
Other mechanisms that correct functional habits include the prevention of the
tongue to rest on the anterior teeth (Haryett et al., 1967). These are best identified
as lingual or palatal cribs (Figure 2.3) (Subtelny & Sakuda, 1964; Torres et al.,
2006) and spurs (Justus, 2001; Meyer-Marcotty et al., 2007). Cribs are usually
attached to the palatal surface of the upper arch and allow the sucking to stop as
they act as a digit-inhibiting tool (Cozza, Baccetti, Franchi, & McNamara, 2006;
Haryett, Hansen, & Davidson, 1970; Huang et al., 1990; Parker, 1971; Villa &
40
Cisneros, 1996). The palatal or lingual cribs are also designed to prevent the
tongue from resting on the teeth and in turn correcting the AOB (Subtelny &
Sakuda, 1964). These structures are smooth and purposefully enable the tongue
to rest on them so that in several cases it may block the functional restoration of
the tongue. Hence the tongue then returns to its original position resulting in
relapse of AOB (Rogers, 1927)
There is an agreement until automatic movements are established, these devices
should be fixed to restore the oral function (Meyer-Marcotty et al., 2007;
Nogueira, Mota, Nouer, & Nouer, 2005). A study conducted by (Giuntini, Franchi,
Baccetti, Mucedero, & Cozza, 2008) described the use of crib therapy with two
different approaches; fixed with a quad-helix, or removable using a removable
plate. The crib attachment to the quad-helix showed greater effectiveness than
the removable plate with fixing the AOB.
This could be due to factors such as compliance, where the removable plate
depends on duration of patients wearing it, while the quad-helix is fixed and has
free-compliance factors (Cozza et al., 2006). In spite of a not so significant
difference between both methods, a previous study proved that the quad-helix to
be clinically successful in 90% of patients with AOB as opposed to 60% for the
removable plate with the crib attachment (Cozza et al., 2006).
41
Figure 2.3: Maxillary palatal crib. The extensive dimension vertically allows ample incorporation of the open-bite region (Torres et al., 2006, p. 612).
Spurs on the other hand were first described by Rogers in 1927 in treating three
AOB cases (Rogers, 1927). These spurs were bonded to a palatal arch and
positioned from canine to canine (Figure 2.4) (McRae, 2010). All cases were fixed
through normalising the tongue posture. Numerous types of comparable
apparatuses were later explained in which spurs can be welded to the lingual
surfaces of maxillary incisor bands or attached to palatal or lingual arches or,
otherwise fused to the lingual or palatal surfaces of the incisors (Nogueira et al.,
2005).
In spite of their effectiveness, treatments of AOB using spurs are sometimes seen
as traumatic (Parker, 1971; Subtelny & Sakuda, 1964) even though no reports
have yet to mention any pain of injury caused to the tongue (Justus, 2001). Spurs
stimulate a change in the tongue resting position, hence enabling tooth eruption
and closure of the open bite (Justus, 2001).
42
Figure 2.4: Lingual bonded spurs. a and b are examples of lingual bonded spurs bonded to the maxillary and mandibular incisors. C is an example of lingual bonded spurt appliance used to correct anterior tongue posture or digit-sucking habits. d the same subject as in photograph a and b with 8 spurs bonded to the upper and lower incisors. Note the difference in aesthetic between the spurs in and b in comparison to c (McRae, 2010, p. 6).
Research had previously shown that tongue activity and position to play a key
role in the challenges associated in reaching long-term stability of AOB treatment
(Dung & Smith, 1988; Haryett et al., 1967; Nogueira et al., 2005). It was hence
decided that utilising banded-spur appliances correct the anterior tongue
pressure and preserve long-term stability of modifying the AOB (Haryett et al.,
1967; Huang et al., 1990). Using the lingual spurs had led to AOB closure through
preventing the tongue pressure on the anterior dentition as well as influence on
the patient to discontinue digit-sucking by functioning as a barrier (Haryett et al.,
1967; Huang et al., 1990).
A study conducted by Cassis, de Almeida, Janson, de Almeida-Pedrin, and de
Almeida (2012) showed significant improvement in the correction of AOB with
43
spur treatment. There was significant reduction in the gonial angle, increased
overbite, palatal tipping of the maxillary incisors and vertical dentoalveolar
development of the mandibular and maxillary incisors (Cassis et al., 2012).
Moreover, when a chincup was incorporated in the treatment it led to a greater
decrease of the gonial angle (Cassis et al., 2012; Huang et al., 1990).
Figure 2.5: An illustration of chin cup therapy to correct malocclusion which led to the decrease of the gonial angle (Torres et al., 2006, p. 612).
This change of tongue position modifies sensory perception by the brain, thus
creating a new motor response which can be permanently imprinted by the brain
(Justus, 2001; Meyer-Marcotty et al., 2007). This clarifies the permanent change
in tongue posture created by spurs and resulting in AOB treatment stability
(Justus, 2001; Meyer-Marcotty et al., 2007).
2.1.5 Burdens of AOB on the Community
Literature have shown a strong association between self-esteem and
malocclusion, particularly AOB, protrusion (overjet) and Angles Class III
44
malocclusions. It is suggested that early treatment of children with hyperdivergent
skeletal phenotypes, such as in AOB, is beneficial in that it enhances physical
appearance and improve self-esteem for the child (English, 2002). Furthermore,
prolonged non-nutritive sucking habits, which essentially leads to malocclusions
such as Angles Class II and AOB is not socially accepted. This can generate
negative response and thus affect the child’s self-esteem.
In contrast, children who had undergone surgical and/or orthodontic treatments
to correct AOB have reported to have significant improvement in their facial
appearance, self-confidence and social interactions (Hoppenreijs et al., 1999). In
addition to the physical appearance issues, there is a financial burden associated
with the management and treatment of AOB, in that treatment requires
multidisciplinary approach, in which individuals from regional, rural and remote
communities are unable to afford or access in terms of their geographic location
and disposable incomes.
2.2 STATE OF THE PROBLEM
In terms of the research methodologies, all studies displayed various prevalence
rates of AOB in the respective populations studied as well as the link and effects
of several determinants, including, but not limited to digit/thumb sucking, bottle-
feeding, pacifier use, mouth-breathing tendencies, and social demographics.
AOB has long been regarded as a complex malocclusion to treat/manage with
correction being highly prone to relapse and thus prevalence is difficult to assess
(Burford & Noar, 2003; Epker & Fish, 1977; Subtelny & Sakuda, 1964). This is
due to a multifactorial aetiology, involving skeletal, dental, neurologic, habitual
and respiratory (Burford & Noar, 2003; Cooke, 1980; Subtelny & Sakuda, 1964).
45
Furthermore, very limited literature discussed the extent of prevalence associated
with AOB amongst children with mixed dentition and its relation to the causes by
environmental factors such as finger or thumb-sucking oral habits. Moreover, to
the best of our knowledge, there is a lack in the literature regarding the
prevalence of AOB and non-nutritive sucking in children living in regional and/or
rural communities. In this study, the growing patient (age seven to 12 years) will
be the target group, where children from the regional town of Orange, New South
Wales, Australia, will be involved in identifying prevalence of this malocclusion
amongst this age range.
In conclusion, this review suggests that there is considerable evidence on the
influence of thumb sucking on the development of AOB. There is a paucity of
research that outlines the main cause of AOB as well as the prevalence of it in
the population, with some suggesting the prevalence of AOB to range from 1.5%
to 46%.
There is also limited literature on effects of AOB on the community, particularly in
regional and rural geographic locations. There is a need for a robust study to
evaluate the association between non-nutritive sucking habits, particularly thumb-
sucking and AOB, and that the prevalence of AOB in those individuals. The
current study will assess the association between non-nutritive sucking habits on
AOB and take into consideration environmental influences.
46
CHAPTER THREE
METHODOLOGY
47
3.1 RESEARCH QUESTION
The purpose of the research was to identify the prevalence of the non-nutritive
sucking habits (such as finger/thumb-sucking, pacifier, and other objects) and
determinants on AOB in primary school children aged seven to 12 years.
3.2 AIMS and OBJECTIVES
1. To report and evaluate the prevalence of oral habits and AOB in children
aged seven to 12 years.
2. To investigate the clinical occlusal relationship and oral habits in children
aged seven to 12 years.
3. To investigate the association between non-nutritive sucking and AOB in
children aged seven to 12 years.
3.3 STUDY VARIABLES
The dependent variable in the present study was AOB. AOB was measured
against all other variables, including thumb-sucking, duration of thumb-sucking,
age of onset of thumb-sucking, non-nutritive sucking such as pacifier use or other
objects, feeding modalities (breastfed, bottle-fed, mixed-fed), sleeping issues,
surgical procedures and orthodontic intervention. Furthermore, child’s age,
gender, sequence within their family household and the highest level of education
of the parent completing the form were assessed.
3.4 OVERVIEW OF METHOD
The sample was chosen from a regional town located in the central west of New
South Wales that is representative of many regional towns in Australia in terms
of population size and distribution of social demographics. It has been reported
48
that there is lack in number of healthcare services and affordability in regional,
rural and remote towns of Australia. Australia is one of the most sparsely
populated countries in the world, comprising of only two individuals per square
kilometre, with the majority of the population (86%) concentrated in urban
locations (Perera et al., 2010). It is noted that Australians are one of the healthiest
populations in the world, but there are well-documented proof to suggest that
there is inequality and inequity of distribution to healthcare service access, with
oral health being one of them (Spencer, 2004; Spencer & Harford, 2007). These
aspects led to the selection of Orange, New South Wales.
3.5 DATA COLLECTION
The data collection took place between August and December 2018. All public
and private primary schools in Orange, New South Wales were invited to
participate in the study, which comprised of 6 public and 6 private primary
schools. Data on the schools present in the region were obtained from The
Department of Education New South Wales. Data on enrolment numbers of
children in those schools were extracted from Extracted from NSW Health
Education Public Schools and NSW Public School February Census Enrolment
data.
Each school was provided with an information sheet on the research project. An
appointment with the school principal was made to formally introduce the
research and purpose of the research. The principal was then given an
information sheet and a consent form to complete and return by mail if agreeing
to participate in the study. One primary public school accepted to participate in
the study. Children enrolled were all given an information sheet, consent form
49
and questionnaire inside an envelope to take home. Parents/guardians of
children enrolled, who accepted to participate completed the questionnaire and
consent form. They then returned it in the return envelope provided and were
instructed to place it in a collection box at the school office.
The questionnaires included questions regarding age and sequence of child
within their family household, highest schooling level of parent completing the
questionnaire, child’s milk feeding patterns (natural and/or artificial), respiratory
aspects, history of ear disease, adenoids or tonsil removal, non-nutritive sucking
habits (pacifier use, digit/thumb-sucking) as well as duration and frequency of the
habits (Appendix 3). Parents/guardians were also given illustrations of different
dental bites and were provided with step-by-step instructions on how to identify
and select which category best describes their child’s dental bite (Appendix 4)
(Proffit et al., 2014). A contact number was provided to parents in the event of
requiring some clarification on any aspect of the questionnaire.
Socio-demographic factors, level of parents’ education, as well as the child’s date
of birth and gender were collected to obtain accurate information on the
prevalence based on age, gender and socioeconomic determinants. In addition,
factors regarding both method and duration of the infant feeding modality (Galán-
Gónzalez, Aznar-Martin, Cabrera-Dominguez, & Dominguez-Reyes, 2014).
Concerning the non-nutritive sucking, parents/guardians were asked whether
their children regularly sucked on pacifiers and/or developed finger sucking
habits.
50
Data were then analysed. The participants who were included in the study were
children attending a public primary school in Orange, New South Wales. The
children targeted were between the ages seven and 12 years (males and
females). The questionnaire as well as the inclusion and exclusion criteria were
designed based on previous studies (Cardoso et al., 2014; Charchut, Allred, &
Needleman, 2003), but were slightly modified to fit the purpose of the present
study.
3.6 SELECTION CRITERIA
Children with grossly decayed anterior teeth, cleft lip/palate, as well as language
barrier, non-compliant and intellectual disability, were excluded from the study. In
the protocol for the pilot study, dental decays were to be examined and identified
by the researcher; the clinical examination was replaced with a parent report and
none of the parents reported any grossly decayed anterior teeth in the child’s
mouth. Decayed teeth were identified as extensive tooth decay that results in
near complete destruction/loss of the crown due to caries. The criteria were
based on excluding any variations that may influence the occlusion of those
children. Furthermore, excluding language barrier allows for fully informed
consent by parents/guardians and children in the participation of this study.
The criteria aimed to prevent deviations and minimise errors (Lochib, Indushekar,
Saraf, Sheoran, & Sardana, 2015). The inclusion criteria were based on young
children that are old enough to have coherence to comply with the study and have
a mixed dentition and young enough to not be indicated for orthodontic treatment.
At the age of 12, children who still present with a non-functional dental bite
(malocclusion) are indicated for orthodontic intervention (Proffit et al., 2014). The
51
prevalence of the occlusal disharmony which includes AOB, overjet (protrusion),
cross-bite and deep bite were noted. The terms in lay language were used in the
questionnaire to help parents and guardians to understand and consequently
‘overjet’, ‘under bite’ and ‘over bite’ were used to indicate protrusion, cross-bite
and deep bite, respectively.
52
3.7 STATISTICAL ANALYSIS
The statistical analysis was undertaken using JMP software (JMP®, Version 14.
SAS Institute Inc., Cary, NC, 1989-2019). An artificial neural network was
developed and trained using Neural Designer Software (Neural Analyser version
2.9.5) to better understand the multi-variate relationship amongst variables.
The statistical significance was calculated using Chi-Square analysis for nominal
data and Student’s t test for continuous data. The Pearson Chi Square (X2) test
was employed for categorical data with normal distribution and the Likelihood
Ratio Chi-Square (G2) test for categorical data without normal distribution. The F
test analysis of variances was used to determine statistically significant
differences within grouped data. A P value less than 0.05 was considered
significant.
53
3.8 ETHICAL CONSIDERATIONS
The research study was first approved by the Ethics committee, Charles Sturt
University, protocol number H17123 (approved end date November 2019).
Participants had the right to refuse participation in the study and the right to pull
out of the study at any point during the research being conducted. No personal
information was collected or distributed. All data collected were kept in a safe,
password protected file, accessible only by the research team.
54
CHAPTER FOUR
RESULTS
55
4.1 DESCRIPTIVE ANALYSIS
A total of 208 children aged between seven to 12 years participated in the study.
The demographic characteristics are summarised in Table 4.1. The mean age of
the participants was nine with a 95% confidence interval (CI) of the mean of 8.8-
9.2 years. Of the 208 participants, 51.4% were female, 47.1% male and 1.4% did
not identify by gender. With respect to the sequence within the family unit each
child was born, 68 (32.9%) were second-born, 54 (26.1%) were third-born, 53
(25.6%) first-born, 25 (12.1%) fourth-born, six (2.9%) fifth-born and only one
sixth-born. The highest educational level for the parents of the participants
involved included 28 (13.5%) completing secondary school, 108 (51.9%)
completed TAFE qualifications, 53 (25.5%) completed tertiary education and 19
(9.1%) completed postgraduate education (Table 4.1).
Table 4.1: Demographic characteristics of the sample population.
Characteristics Frequency (n) Percentage (%)
Age (years)
Mean ± SD
9 ± 0.2
___
Gender
Female Male
107 98
51.4% 47.1%
Sequence of child
First-born Second-born Third-born Fourth-born Fifth-born Sixth-born
53 68 54 26 6 1
25.6% 32.9% 26.1% 12.1% 2.9% 0.5%
Parent’s highest educational level
Secondary TAFE Tertiary Post-graduate
28 108 53 19
13.5% 51.9% 25.5% 9.1%
In relation to the oral habits of the participants, 47 (22.6%) have reported to have
had carried out thumb-sucking habits (Table 4.2). Of those that reported thumb-
sucking, 29 (61.7%) had carried out the habit for 12 months or more, 11 (23.4%)
56
had carried out the habit for more than 6 months but less than 12 months, while
7 (14.9%) had carried out the habits for six months or less. A number of the
participants reporting thumb sucking (18 or 38.3%) had commenced this habit at
the age of six months, while 12 (25.5%) had commenced the habit at 12 months
and 13 (27.7%) commenced at the age two to five years.
A total of 88 (42.5%) participants have had mixed feeding between breastfeeding
and bottle-feeding, while 62 (30.0%) were exclusively breastfed and 57 (27.5%)
exclusively bottle-fed (Table 2). Furthermore, a total of 93 (44.7%) participants
have used a pacifier, while 49 (23.6%) participants had not displayed any non-
nutritive sucking behaviour. In addition, 31 (14.9%) participants have used both
pacifier and thumb-sucking while 24 (11.5%) used other objects as non-nutritive
sucking behaviours, and only 11 (5.2%) have used thumb-sucking exclusively.
Amongst the 208 participants, 32 (15.4%) had snoring issues during sleep, 36
(17.3%) had both snoring and mouth-breathing issues during their sleep, mouth-
breathing alone reported in 16 (7.7%) participants, six (2.9%) reported snoring
and sleep-apnoea, and four (1.9%) reported sleep-apnoea alone. With respect to
surgery, 27 (13.0%) reported tonsils and adenoids being removed, 12 (5.8%) had
only tonsils removed, 18 (8.6%) had grommet surgery, eight (3.8%) had grommet
and adenoid surgery and four (1.9%) had adenoid surgery. There were 188
(90.4%) of participants who had not had or were undergoing any orthodontic
treatment or intervention, while 20 (9.6%) were or have had some orthodontic
intervention carried out. The frequency of dental occlusion present in the sample
included 72 (35.5%) participants with an overbite, 49 (24.1%) had AOB, 23
57
(11.3%) had protrusion, six (3.0%) had a cross-bite and 53 (26.1%) had a normal
class I occlusion (Figure 4.1).
Table 4.2: Descriptive Statistics Summary of the variables and occurrence frequency in the sample population.
Characteristics Frequency (n) Percentage (%)
Oral Habits
Thumb-sucking Duration of thumb-sucking Age commenced thumb-sucking
≤6 months 6-12 months >12 months 6 months 12 months 2-5 years
47 Total 7 11 29 18 12 13
22.6% 14.9% 23.4% 61.7% 38.3% 25.5% 27.7%
Feeding modalities
Breastfed Bottle-fed Mixed-fed
62 57 88
30.0% 27.5% 42.5%
Sleeping issues
Mouth breathing Snoring Sleep apnoea Snoring & mouth breathing Snoring & sleep apnoea
16 32 4 36 6
7.7% 15.4% 1.9% 17.3% 2.9%
Surgical procedures
Adenoidectomy Tonsillectomy Grommets Adenoidectomy & tonsillectomy Adenoidectomy & grommets
4 12 18 27 8
1.9% 5.8% 8.6% 13% 3.8%
Orthodontic intervention (previous or current)
20 9.6%
Occlusion
Normal Angle’s Class I Protrusion cross-bite Overbite Anterior open bite
53 23 6 72 49
26.1% 11.3% 3.0% 35.5% 24.1%
58
Figure 4.1: Incidence of various bites in the sample population (centre), and prevalence of thumb sucking for bite cluster (green indicating there is no history of thumb sucking and red indicating a history of thumb sucking).
59
4.2 INFERENTIAL ANALYSIS
No statistically significant relationship was noted between the type of bite (normal,
cross-bite, protrusion, over bite or open bite) and the child’s age at presentation
(P=0.1786), the child’s gender (P=0.918) or whether the child had orthodontic
intervention (P=0.1217) (Table 3). A statistically significant correlation was noted
between the sequence a child was within their family structure (first born, second
born etc.) and type of bite (P=0.0109). Children born after the first child in a family
unit (second to sixth) were 5.2 times more likely to have an abnormal bite that a
first child. The second child demonstrated 6.8 times higher likelihood of having a
cross-bite compared to all other children. Children who were not first born
(second to sixth in their family sequence) were 2.3 times more likely than first
born children to develop an overbite or AOB, and 2.1 times more likely to
specifically develop an AOB (Table 4.3).
Table 4.3: Statistical relationship between variables and the type of bite. Item P value Odds ratio (OR)
For abnormal bite* Odds ratio (OR) for
anterior open bite or over bite
Age of child (years) 0.1786 - -
Gender (Male/Female) 0.918 - -
Sequence of child 0.0109 5.15 (2nd to 6th born) 2.3 (2nd to 6th born)
Schooling level of parent (Secondary/TAFE or Tertiary/Postgraduate)
<0.001 3.0 (Secondary/TAFE) 1.4 (Secondary/TAFE)
Thumb sucking <0.001 - 4.3
Duration of thumb-sucking (<6 months, 6-12 months, >12 months)
<0.001 5.15 (more than 6 months) -
Age of onset of thumb-sucking (<6 months, 6-12 months, >12 months, 2-5 years)
0.0334 - -
Feeding modalities (breast, bottle, mixed)
0.002 5.2 4.2
Non-nutritive sucking behaviours
<0.001 1.8 1.5
Sleeping issues (snoring, mouth-
<0.001 6.2 5.1
60
breathing, sleep apnoea
The need for surgical procedures (tonsillectomy, adenoidectomy, grommets)
<0.001 3.4 2.7
*Abnormal bite comprises all malocclusions assessed in this study (open-bite, deep bite, cross-bite and
protrusion)
A statistically significant difference was noted in bite against the parent’s level of
schooling (P<0.001) with a 3.0 odds ratio (OR) of developing an abnormal bite
for children whose parents’ highest level of schooling was Secondary/TAFE than
Tertiary/Postgraduate levels of education. More specifically, a 1.4 OR was
determined for developing a deep/open bite for children whose parents’ highest
level of schooling was Secondary/TAFE compared to the Tertiary/Postgraduate
levels of education.
Thumb sucking also demonstrated a statistically significant correlation with
abnormal bite (P<0.001) (Table 4.3). There were no cases of development of a
deep bite or open bite in the absence of thumb sucking. All reported cases of
thumb sucking reported an abnormal bite (either protrusion, deep bite or open
bite). Thumb sucking was 4.3 times more likely to lead to an over or open bite
than no thumb sucking. Indeed, the presence of thumb sucking was able to
predict the presence of a deep or open bite with a sensitivity of 97.9% although
the specificity of 51.9% indicates not all thumb suckers develop a deep or open
bite. While there were fewer cases of open bite, thumb sucking had a 44.4 times
higher probability of developing an open bite than for non-thumb suckers. The
sensitivity and specificity of thumb sucking in predicting open bite of 78.7% and
92.3% respectively supports a predictive relationship. The presence of thumb
sucking increased the risk of a protrusion by 2%, a deep bite by 19% and an open
bite by 78.7%.
61
Similarly, the duration of thumb sucking demonstrated a statistically significant
association with bite (P<0.001) (Table 4.3). No child with a duration of thumb
sucking less than six months developed an open bite. While all children who
reported thumb sucking developed a bite abnormality, a duration of thumb
sucking of more than six months saw 92.5% develop an open bite. The age at
which thumb sucking started also showed a statistically significant correlation
with bite (P=0.0334) with the earlier onset increasing risk for protrusion by 8.3%,
deep bite by 25.0% and open bite by 66.7%. 100% of children in whom thumb
sucking commenced between the ages of two to five years developed an open
bite.
With respect to feeding methods, a statistically significant correlation was
demonstrated with bite (P=0.002). Children who were bottle-fed were 1.9 times
more likely to have an open bite than children who were breastfed. Furthermore,
children who were fed with mixed-methods or were bottle-fed combined were
15.2 times more likely to have an open bite than breastfed children. Breast
feeding a child provides a protective effect for the development of abnormal bites
with an OR of developing an abnormal bite of 0.2 compared to an OR of 5.2 for
developing an abnormal bite for those that were bottle fed. More specifically,
bottle feeding had a 4.2 OR for developing a deep or open bite compared to
breast feeding.
Non-nutritive sucking behaviours demonstrated a statistically significant
relationship with abnormal bite (P<0.001). Use of a pacifier as opposed to no non-
nutritive sucking was associated with 1.8 OR for developing an abnormal bite, 1.5
62
specifically for a deep or open bite, but only 1.3 OR for open bite. When a pacifier
was used in combination with thumb sucking, however, the OR for developing a
deep or open bite was 15.1 and specifically for an open bite of 10.8.
Children who snored were 6.2 times more likely (OR) of having an abnormal bite
and 5.1 times more likely to have an open bite than those with no sleeping issues
(P<0.001) with 37.5% of children reporting an open bite also having snoring
issues during their sleep. Moreover, children who had snoring issues and were
also mouth-breathers were 19.3 times (OR) more likely to have an open bite than
children with no sleeping issues; 69.4% of children who had an open bite
displayed both snoring and mouth-breathing sleeping issues.
A statistically significant relationship was also noted between abnormal bite in
children and the need for surgery (P<0.001) (Table 4.3). Any surgery associated
with tonsils, adenoids or grommets had an OR for developing a bite abnormality
of 3.4 and deep or open bite of 2.7. Specifically surgery for tonsils and/or
adenoids has an OR for developing a deep or open bite of 6.2, and for open bite
specifically of 7.7.
4.3 MULTI-VARIATE ANALYSIS
Given the nature of the data is largely nominal rather than continuous, correlation
parameters and traditional multi-variate analysis is inappropriate. There is some
merit to principal component analysis using factor analysis to produce
eigenvalues with eigenvalues representing the relative contribution to total
variability of the dataset (Figure 4.2).
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Figure 4.2: Factor analysis and eigenvalues highlighting four or perhaps five key variables.
While this provides an insight into the cumulative effects of data, it does not
provide a deep insight into the interaction amongst variable. This is probably best
done with neural network analysis. The scree plot (Figure 4.3) suggests that there
are four main factors to consider. These factors present outcomes independently
and show a strong correlation with one another. Factors with eigenvalues of less
than 1.0 were not considered, as it may weaken the overall predictive power.
The scree plot is a procedure that is used to identify a number of factors to retain
in factor analysis which was proposed by Cattell (1966). The eigenvalues are
plotted against their ordinal numbers and an analysis is done to identify where a
break or a levelling of the slope of the plotted line takes place. Tabachnick and
Fidell (2001) referred to the break point to be the point where a line drawn through
the points changes direction. The number of factors is indicated by the number
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of error variance. An eigenvalue is the amount of variance that a particular
variable or component contributes to the total variance. This corresponds to the
equivalent number of variables that the component represents (Tabchnick and
Fidell, 2001).
Figure 4.3: Scree plot with eigenvalue cut-offs suggesting four principle values for deeper exploration.
65
Excluding relationships amongst variables against the child’s bite outlined above,
no statistically significant differences or relationships were noted across variables
for the sequence the child was born in the family nor gender, (P > 0.05). Thumb
sucking was statistically higher for children whose parents had secondary or
tertiary as their highest level of education (P=0.0005) compared to TAFE and
post graduate with no thumb sucking reported amongst the latter population. The
type of feeding also has a statistically significant variation based on parents level
of schooling (P<0.001) with an OR of breast feeding of 8.2 for secondary levels
of education compared to all other levels (tertiary, TAFE, post graduate). The
highest likelihood of sleep issues was reported where TAFE was the highest level
of education and lowest for secondary education (P<0.001). Post graduate
education levels for parents had a statistically higher likelihood of surgery
(P<0.001).
Breastfed children were less likely to thumb suck (P<0.001) with a protective OR
of 0.12. Thumb sucking is 11.3 (OR) times more likely in the presence of sleep
issues (P<0.001) and 3.0 times (OR) in those who had surgery (P<0.001). The
age of onset and duration of thumb sucking were strongly associated with earlier
onset suggesting longer duration (P<0.001) although later onset with prolong
duration of thumb sucking being a significant predictor of open bite.
4.4 NEURAL ANALYSIS
4.4.1 Combined Deep Bite and Open Bite
A neural network was developed and trained using Neural Designer Software to
better understand the multi-variate relationship amongst variables. The bite was
converted to a binary outcome (target) of the child having and deep bite or open
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bite (yes) or having another type of bite (no). All other variables were classified
as input variables. A correlation matrix was produced and this identified
redundancy in the variables. That is, multiple variables that independently predict
the outcome, but which show a strong correlation with one another, may weaken
the overall predictive power because the eigenvalues are less than 1.0. Thus,
eliminating redundancy can identify principal components and minimise
predictive error. The strength of the logistic relationship between each input and
binary output was determined and ranked (Table 4.4). While key variables were
identified, no specific redundancy was determined.
Table 4.4: Neural analysis and rank of variables against the binary outcome.
Variable Deep Bite and Open Bite
Thumb Sucking 0.568
Sleep Issues 0.503
Surgery 0.393
Feeding Type 0.33
Duration of Sucking 0.254
Sequence 0.18
Non-nutritive sucking 0.174
Parents Level of School 0.135
Age 0.0968
Ortho 0.0626
Age of Habit 0.0497
Gender 0.0391
The quasi-Newton method is used as the training algorithm and is based on
Newton's method but does not require calculation of second derivatives. Instead,
the quasi-Newton method computes an approximation of the inverse Hessian at
each iteration of the algorithm, by only using gradient information. The final
architecture of the neural network can be written as 8:6:4:1 (Figure 4.4).
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Figure 4.4: The final architecture inclusive of eight variables and a binary outcome.
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A good way to evaluate the predictive efficacy of the model is to plot a ROC
(Receiver Operating Characteristic) curve. This predictive capability is measured
by calculating the area under curve (AUC) which in this model was 0.86. That is,
using these variables and the neural network provides identification of children
with a deep or open bite with 86% accuracy (Figure 4.5).
Figure 4.5: ROC plot with AUC of 0.86.
4.4.2 Open Bite Only
A similar neural network was developed and trained where the bite was converted
to a binary outcome (target) of the child having an open bite (yes) or having
another type of bite including deep bite (no). All other variables were classified
as input variables. A correlation matrix was produced and no redundancy
69
detected. The strength of the logistic relationship between each input and binary
output was determined and ranked (Table 4.5). The neural network resulted in a
final architecture the same (Figure 4.4) but an AUC for the ROC of 1.0. That is,
for predicting open bite, an accuracy of 100% was achieved using calibrated
weightings for the input variables. This neural network is programmable in python
language and readily incorporated into a mobile (phone) app for risk assessment
for parents.
Table 4.5: Neural analysis and rank of variables against the binary outcome.
Variable Open Bite
Thumb Sucking 0.754
Duration of Sucking 0.574
Orthodontic intervention -0.474
Feeding Type 0.291
Parents Level of School 0.261
Sleep Issues 0.24
Age 0.183
Gender 0.177
Surgery 0.156
Non-nutritive sucking 0.128
Age of Habit 0.113
Sequence 0.0233
4.4.2.1 Method
The data was evaluated using an artificial neural network (Neural Network version
2.9.5). There were 15 input variables and a single binary output of reported open
bite or no reported open bite. Following logistic regression and principal
component analysis, 15 inputs were reduced to just 2; thumb sucking (0.754) and
duration of thumb sucking (0.574).
The network architecture included 2 scaling layer inputs, 2 hidden layers of 3 and
1 node respectively using a logistic activation function (Figures 4.6 and 4.7)
(defines the output of each node based on its input) for a single probabilistic layer
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(binary). The weighted squared error method was used to determine the loss
index. A Quasi-Newton training method was employed using gradient information
to estimate the inverse Hessian for each iteration of the algorithm (no second
derivatives). The loss function (0.531) associated with the training phase
estimates the error associated with the data the neural network observes. The
selection loss (0.307) is a measure of the neural networks agility; generalisability
to new data. This indicates the need to optimise the number of hidden layers /
iterations in the final architecture. The final training architecture identified 2
scaling layer inputs, 2 hidden layers of 1 node each and a single probabilistic
layer (binary).
Figure 4.6: Initial neural network architecture using only 2 inputs, 2 hidden layers of 2 and 1 nodes respectively, and a single binary output.
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Figure 4.7: The logistic activation function defines the output of each node based on its input for a single probabilistic layer.
4.4.2.2 Results
Figure 4.8: Final neural network architecture using only 2 inputs, 2 hidden layers of 1 node respectively, and a single binary output.
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A number of metrics can be employed to test the errors in the neural network.
The final architecture was evaluated using a number of tests (Table 6) indicating
robust validation. Using receiver operator characteristics (ROC) analysis
demonstrated an area under the curve of 0.889. This correlates with a sensitivity
of 77.8%% and specificity of 100% and this is reflected in the confusion matrix
(77.8% true positives, 100% true negatives, 22.2% false negative and 0% false
positive).
Table 4.6: Validation error tests for the final architecture.
Training Selection Testing
Mean squared error 0.165321 0.128456 0.0919856
Cross-entropy error 0.482252 0.410326 0.310291
Weighted squared error 0.723807 0.385368 0.367942
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CHAPTER FIVE
DISCUSSION
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The aetiology of malocclusion is linked to both hereditary and environmental
influences (Corruccini & Potter, 1980; Heimer et al., 2008; Peres, Barros, et al.,
2007; Vig & Fields, 2000). Environmental variables include tongue posture,
pacifier use, finger/thumb-sucking habits as well as other social determinant
factors (Chevitarese et al., 2003; Hebling et al., 2008). Genetic Influences include
formation and development of the orofacial structures (Corruccini & Potter, 1980).
In this study, AOB has been shown to have a very strong correlation between
both nutritive (feeding modalities) and non-nutritive (thumb-sucking, pacifier use)
sucking habits. The clinical interest to better understand the aetiology and early
diagnosis of AOB malocclusion lead to the construction of this study. There is a
need to take into consideration that AOB malocclusion may require professional
assistance to aid in cessation of unwanted, causative, behavioural habits in the
early stages of life. These may include counselling and/or orthodontic
interventions to name a few.
The logistics regression model used in this study allowed for distinct calculations
of OR values for the different variables associated and analysed. The results from
this study found a very strong association between thumb sucking, duration of
thumb sucking and AOB. Those who sucked their thumb had a distinct Odds
Ratio of 4.3 times more likely to develop an AOB or deep bite. Furthermore, those
who sucked their thumb for a duration of 6 months or longer, were 5 times more
likely to have an abnormal bite. It was also noted that the presence of pacifier
use did little in the causative effect on AOB unless combined with thumb-sucking
habits with an OR of 1.8 to lead to an abnormal bite and an OR of 1.5 to result in
AOB or deep bite. Sousa, Ribeiro, et al. (2014) outlined the link between duration
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of pacifier use and AOB, where a duration longer than 36 months resulted in a
larger prevalence of AOB. Other studies found a relationship between pacifier
sucking for a long period and AOB (Bishara et al., 2006; Peres, Barros, et al.,
2007) while this current study identified the thumb-sucking to be the more
significant influence to developing AOB.
Feeding modalities also yielded an OR of 5.2 of bottle-fed children to have an
abnormal bite and 4.2 specific to AOB and deep bite. This suggests that those
who were bottle-fed or mixed-fed were more likely to develop a malocclusion than
breastfed children. Romero et al. (2011) identified that the analysis of the
relationship between prevalence of AOB and breastfeeding outlined that
exclusive breastfeeding between six to 12 months, or breastfeeding beyond 12
months of age played a positive role in dental occlusion in contrast to the absence
of breastfeeding, where the best positive outcome was for a duration of longer
than 12 months. Furthermore, sleeping issues such as snoring and mouth-
breathing identified a causative link to AOB and all other malocclusions, with an
odds ratio of 6.2 developing an abnormal bite if they had snoring issues and 5.1
to develop AOB and deep bite.
5.1 DEMOGRAPHICS
The current study examined children aged seven to 12 (in their mixed dentition
stage) in a regional town, New South Wales, Australia. To the best of our
knowledge, this study may be the only study that had incorporated only the mixed
dentition stage in Australia. The majority of studies evaluated the prevalence and
effect of non-nutritive and nutritive sucking habits on AOB at the deciduous
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dentition stage in various parts of the world including South America, Asia and
Africa.
A study conducted in Brazil examined feeding and non-nutritive sucking habits
and open bite prevalence, the sample group employed individuals ranging from
three to 18 years of age with Downs’ Syndrome (Oliveira et al., 2010). It had
similar results to the current study, identifying that longer duration of bottle-
feeding or less than 6 months duration of breastfeeding had causative
associations with open bite and cross bite. Finger/thumb-sucking was only
associated with a posterior cross-bite for the sample population they employed
(Oliveira et al., 2010). The current study had also incorporated other variables,
such as onset of feeding for a bigger sample size.
Another study by Cozza, Baccetti, et al. (2005) evaluated sucking habits and
facial hyperdivergency as risk factors for AOB in the mixed dentition. They
concluded that thumb-sucking for a prolonged duration as well as hyperdivergent
facial characteristics influence the development of AOB in the mixed dentition.
The current study did not take into consideration growth patterns, instead it
exclusively analysed behavioural causative factors such as nutritive and non-
nutritive sucking habits, and is in agreement Cozza, Baccetti, et al. (2005) in that
thumb-sucking plays a significant role in the development of AOB malocclusion.
In a longitudinal study by Ovsenik, Farčnik, Korpar, and Verdenik (2007) revealed
how morphological and functional traits of malocclusion altered during growth and
development. The study results identified that in 50% of the children examined,
a morphological malocclusion severity score from mild to severe was noted at
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three years of age and increased towards the end of the mixed dentition stage.
With using other classification methods, this high prevalence was in agreement
with another study by Thilander et al. (2001).
According to several studies, gender did not have any effect on development of
AOB (Machado et al., 2014; Peres, De Oliveira Latorre., 2007; Sousa et al.,
2007). The current study is in agreement with this argument, showing equal
distribution of male and female in all the occlusions evaluated, with a P value of
0.918 for relationship between the type of occlusion and the child’s gender.
On the other hand, socioeconomic status was seen as a risk factor in the
development of AOB. Peres, De Oliveira Latorre, et al. (2007) suggested that
lower socioeconomic backgrounds to be determinants of malocclusions,
specifically AOB. Sousa, Pinto-Monteiro, et al. (2014) also agrees with this
conclusion.
In the present study, it was shown that children whose parents highest level of
education to be secondary schooling or TAFE (technical and further education
institutes) were more likely to develop a malocclusion, specifically AOB and deep
bite than the children whose parents highest level of education were either tertiary
or postgraduate. Although level of education may not necessarily shed light on
the economic status and average salary earnings of the participants’ families, it
remains to be a social determinant based on level of education rather than
income estimate.
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Some studies stated that there was no association between socioeconomic
conditions and AOB. They also suggest for further investigations due to the lack
of significant associations between socioeconomic status and AOB in previous
studies (Frazão, Narvai, Latorre, & Castellanos, 2004; Kharbanda et al., 1994).
On the other hand, Warren et al. (2000) discovered that the older mothers who
had a higher level of education were more likely to have children who did not
display non-nutritive sucking behaviours when compared to younger mothers
with a lower level of education. These findings were also established by Farsi et
al. (1997) and Paunio et al. (1993). A similar trait was found in, who identified
similar patterns in the association between pacifier use and the mother’s level of
education (Peres, De Oliveira Latorre, et al., 2007). In the present study, there
was no specifications as to who is required to complete the questionnaire as it
was available for both mothers, fathers and legal guardians. Despite that, similar
results are depicted in the present study, in that parents/guardians of a higher
education level were less likely to have children who presented with non-nutritive
sucking habits.
5.2 QUESTIONNAIRE
The questionnaire used in this study relied upon previous studies conducted on
assessing the prevalence and aetiology of AOB with minor modifications. In a
study by Charchut et al. (2003), questions on previous and current nutritive and
non-nutritive sucking habits were examined, as well as the child’s history of ear
disease, tonsil and adenoid removal. Furthermore, questions on age of onset and
duration of finger/thumb-sucking habits and/or pacifier use as well as questions
on feeding modalities were analysed.
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While another study used a questionnaire that was validated in a pilot study in
Brazil. Questions in this study included child demographics (age, gender, and
household income), feeding modalities, and non-nutritive sucking habits.
Moreover, this study conducted clinical examinations in the school setting of
children’s occlusions using a mouth mirror and dental probe, where they visually
inspected the child’s maximum ICP occlusion (Cardoso et al., 2014).
Another study analysed the length of time the children were exclusively breastfed.
Children were grouped into four groups based on the following question; those
who were never breastfed, those who breastfed for a duration shorter than six
months, those who breastfed between six to 12 months and a final group of those
who breastfed for more than 12 months. Further to these groups, questions on
non-nutritive sucking habits were also incorporated into the questionnaire
(Kobayashi et al., 2010).
A similar study concerning children aged three to six years, attending public
preschools in south-eastern Brazil had a questionnaire examining child’s
demographics (age, gender, and name) as well as method and duration of infant
feeding. Guardians were also asked if their child regularly sucked on pacifiers
and/or had developed finger or thumb-sucking habits (Romero et al., 2011).
A study by Jabbar, Bueno, Silva, Scavone-Junior, and Inês Ferreira (2011),
conducted a similar study using similar questions on feeding modalities, non-
nutritive sucking habits and demographics. It had also outlined exclusion criteria
similar to that of the current study such as exclusion of children with grossly
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decayed/missing anterior teeth, dental anomalies and cleft lip/palate or other
developmental anomalies. Similar to Cardoso et al. (2014), the study by Jabbar
et al. (2011) also involved conducting a clinical examination in the school
environment of children’s occlusions using a mouth mirror and dental probe and
disposable orthodontic rulers.
In the current study, the minor modifications involved including the sequence of
the child within their family household (first born, second born, third born, etc.…),
as well as the highest level of education of the parent completing the
questionnaire. Furthermore, due to the inability to conduct a clinical occlusal
assessment of the children involved, illustrations were included in the
questionnaire, with simple and clear instructions for parents/guardians to follow
and assess their child’s dental bite and then choose the illustration that best fits
the description.
5.3 PREVALENCE
According to literature, the prevalence of malocclusions ranges between 26.0%
to as high as 87.0% (Dhar, Jain, Van Dyke, & Kohli, 2007). The prevalence of
AOB has been inconsistently reported in the literature. In a study by Vasconcelos
et al. (2011), the prevalence was reported to be 32% in the deciduous dentition.
This was higher than the prevalence of AOB in the deciduous dentition reported
by Sousa et al., (2007), which was reported to be 20.6%, but lower than the study
by Peres, Barros, et al. (2007), as high as 46.2% prevalence of AOB reported
who evaluated the prevalence on children aged six years.
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Cozza, Baccetti et al., (2005) Cozza, Baccetti, et al. (2005) reported the
prevalence of AOB to be 18% in the mixed dentition. In the present study, which
assessed the prevalence of AOB in the mixed dentition obtained the prevalence
of AOB from the sample population to be in agreement with the study by Sousa
et al., (2007) with 24% from a sample of 208 participants. The variations in
reported prevalence is due to the sample size and the varying demographics as
well the dentition development stage of the participants.
It has been suggested that the prevalence of AOB declined with advancing age,
indicating self-correction, growth alterations and ceasing of harmful oral habits
(Vasconcelos et al., 2011). Furthermore, the prevalence of non-nutritive sucking
behaviours declined with increased age (Heimer et al., 2008). Some evidence
has revealed that the longer the period of non-nutritive sucking behaviours a child
experiences, the risk of malocclusion in the primary dentition increased (Warren,
Bishara, Steinbock, Yonezu, & Nowak, 2001)This outlines that AOB has the
ability to correct itself if habit ceased by the age of three years.
The results of the current study show that there was no statistical significance
between type of malocclusion or the child’s gender and age at time of research.
Literature have suggested that a significant number of AOB cases can be
reversed if non-nutritive habits ceased at an early age. A longitudinal study stated
that a period of 48 months or more of non-nutritive sucking habits was a risk factor
for AOB (Warren, Bishara, Steinbock, Yonezu & Nowak, 2001).
A study by Vasconcelos et al. (2011) reported the prevalence of AOB to be
significantly associated with feeding type and non-nutritive sucking behaviours,
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but did not have association with gender, age or family income. Similar findings
were described by Peres, Barros, et al. (2007). In this study, AOB was highly
associated with thumb-sucking and duration of thumb-sucking. There was no
significant relationship with gender or age which is in agreement with Peres,
Barros, et al. (2007) and Vasconcelos et al. (2011). In this present study,
participants whose parents’ highest level of schooling was Secondary or TAFE
were 1.4 times more likely to have either a deep bite or an AOB than those whose
parents highest level of schooling was tertiary or postgraduate.
Persistent non-nutritive sucking behaviours have been shown to lead to an
increased prevalence of AOB (Adair et al., 1995; Samir E. Bishara et al., 2006;
del Valle et al., 2006; Ovsenik, 2009; Peres, De Oliveira Latorre, et al., 2007;
Viggiano, Fasano, Monaco, & Strohmenger, 2004). Other factors such as
genetics and environmental influences can affect malocclusion such as AOB.
Studies carried out in North America (Adair et al., 1995) and Brazil (Zardetto et
al., 2002) showed prevalence to be 0% and 1%, respectively, for those without
history of non-nutritive sucking behaviours. In the current study, it was shown that
longer duration of non-nutritive sucking habits, particularly thumb-sucking was
significantly associated with development of AOB.
Other studies in India (Ganesh, Tandon, & Sajida, 2005) and in North America
(Bishara et al., 2006) have shown the prevalence of AOB to be 5.25% and 6.1%,
respectively, for participants who displayed no history of non-nutritive sucking
habits. This can suggest that other factors such as genetics, growth patterns, and
feeding modalities can all have influence in the development of AOB. In the
present study, children who were bottle-fed or mixed-fed had more tendencies to
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develop AOB than those who were breastfed. In addition, children whose parents
had lower levels of education were more likely to develop abnormal occlusions
such as AOB than those whose parents had higher levels of education.
It is complex to compare and contrast for prevalence of AOB between published
articles. This is due to the varying methods employed in different studies, as well
as age differences in the sample populations, examiner subjectivity, particular
objectives and different sample sizes and demographics (Ciuffolo et al., 2005;
Onyeaso, 2004; Silva & Kang, 2001; Thilander et al., 2001). A high number of
studies carried out examining the prevalence of AOB were carried out primarily
on the deciduous dentition, involving participants as young as 36 to 58 months of
age ( Baalack, 1971; Kobayashi et al., 2010; Svedmyr, 1979; Vasconcelos et al.,
2011; Warren et al., 2001).
In relation to deep bite, literature suggests that deep bite prevalence increases in
the mixed dentition (Klocke, Nanda, & Kahl-Nieke, 2002). A study by Worms et
al. (1971) reported self-correction of the AOB to take place from a seven to nine
year old to a 10 to 12 year old sample in 80% of cases. Another study stated that
a slight decrease in deep bite took place from 12 to 18 years (Bergersen, 1988).
In the study by Klocke et al. (2002) revealed an increase in deep bite in relation
to the open bite group of participants, leading to a positive deep bite at 12 years
of age. This suggests that there is a consistent pattern in development of deep
bite which is also consistent with other literature (Bergersen, 1988; Bishara &
Jakobsen, 1998).
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5.4 NON-NUTRITIVE SUCKING
According to Warren and Bishara (2002), non-nutritive sucking habits are
acceptable until the age of three years without causing changes to the orofacial
structures. Persistent habits beyond three years of age can significantly increase
the likelihood of developing undesirable occlusal traits and dental arch at the end
of the primary dentition phase. These prolonged sucking habits, in association
with tongue-thrust swallowing, can result in a mechanical obstruction for the
development of the permanent anterior teeth leading to alterations causing AOB
(Warren & Bishara, 2002).
Ovsenik et al. (2007) argued that sucking habits, even for a short duration, need
to be taken into consideration as having a direct effect on the developing
occlusion as well as an indirect effect due to an alteration in the swallowing
pattern. Based on data of previous studies as well as the current study, sucking
habits is a crucial aetiological factor in influencing the development of the AOB
and hence must be taken into consideration. Ovsenik et al. (2007) also outlined
that sucking habits was a major influence in development of malocclusions as
well as a causative factor seen at the end of the mixed dentition period.
Furthermore, the self-correction for some AOB’s during the transition from mixed
to permanent dentition can take place given the cessation of thumb-sucking
habits. Some more severe AOB’s, that sometimes extend to the terminal molar
region rarely self-corrects spontaneously and will often require invasive and
complex treatment measures (Sandler, Madahar, & Murra, 2011).
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A study by Bishara et al. (2006) noted that finger or thumb sucking was highly
associated with an increased overjet. This is not presented in the present study,
where 96% of children with an overjet (protrusion) did not suck their
fingers/thumb. The high prevalence of sucking habits (40%) by Vasconcelos et
al., (2011), was suggested to be due to socioeconomic status, where more
women were working which led to shorter periods of breastfeeding and thus non-
nutritive sucking habits development in infants. In the present study, it was shown
that children whose parents had lower levels of education were more likely to
develop non-nutritive sucking habits which led to development of malocclusion
characteristics.
Several studies have outlined the main causative factors for AOB were non-
nutritive sucking habits such as thumb and pacifier (Peres, Barros, et al., 2007;
Tornisiello Katz & Rosenblatt, 2005), while others argue that breathing patterns
also has influence on this malocclusion (Klocke et al., 2002). Some even suggest
skeletal patterns to be the main cause (Yousefzadeh, Shcherbatyy, King, Huang,
& Liu, 2010). Another study states the early weaning and dental caries to play a
big role in the development of AOB (Peres, Barros, et al., 2007). In the current
study, the major influences on AOB were identified to be thumb-sucking habits
and duration of thumb-sucking habits.
The high prevalence of AOB seen in the present study may suggest that non-
nutritive sucking habits may not have ceased at an early age suggesting the lack
of self-correction to take place. The results in the present study revealed that
100% of children who had commenced thumb-sucking between ages two to five
years had an AOB. Furthermore, the majority of children (61.7%) who carried out
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thumb-sucking had done it for a duration of 12 months or more. The children who
had an AOB were divided into 21.6% in the 6-12 months duration category while
78.4% in the 12 months of more duration category. There were 92.5% of children
with an open bite who had carried out thumb-sucking for a duration longer than 6
months.
The results are further confirmed by Hebling et al. (2008) who stated that despite
the oral habits being a risk factor in the development of malocclusions such as
AOB, it does not necessarily indicate that this will take place. It is thus, dependent
on intensity and duration of the non-nutritive sucking habits as well as the child’s
facial growth patterns that can lead to an AOB malocclusion. It is shown in the
statistics mentioned above of the current study, children with a longer duration
(12 months of more) of thumb-sucking were more likely to have an AOB than
those who had lower durations of the habits (6-12 months)
5.5 FEEDING MODALITIES
Previous literature have suggested that AOB be associated with non-nutritive
sucking behaviours as well as nutritive sucking behaviours in forms of bottle-
feeding (Bishara et al., 2006; Ganesh et al., 2005; Peres, De Oliveira Latorre, et
al., 2007). Results of the present study showed similar relationships. According
to our findings, children who were bottle-fed or mixed-fed were more likely to have
AOB than those who were breastfed. Bottle-fed participants were 1.9 times more
likely to have an open bite than those who were breastfed, and those who were
mixed-fed were 15.2 times more likely. Moreover, the majority of children in the
current study were either bottle-fed or mixed-fed than exclusively breastfed. The
high prevalence of this has been suggested to be due to the world’s
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industrialisation and modernisation, requiring females to participate in the labour
force, leading to a decreased rate of breastfeeding (Farsi et al., 1997). It has been
argued that factors such as the influence of breastfeeding on development of
AOB is difficult to assess, due to the need to separate these effects from that of
non-nutritive sucking behaviours (Warren & Bishara, 2002).
The World Health Organization recommends exclusive breastfeeding until 6
months of age. This is to reduce the prevalence of gastrointestinal infection and
weight deficit (Kramer & Kakuma, 2012; Organisation, 2011). Breastfeeding has
shown to have an effect on occlusion. Some studies have suggested that
malocclusion can result if infants were breastfed for a period of less than 12
months. It was noted that this may be due to the adoption of non-nutritive sucking
behaviours to fulfil natural sucking needs for comfort (Kobayashi et al., 2010;
Kramer et al., 2001; Narbutyte, Narbutyte, & Linkeviciene, 2013; Peres, Barros,
et al., 2007). Breastfeeding for a prolonged duration was suggested to have a
protective factor against malocclusion, specifically AOB (Sousa, Ribeiro, et al.,
2014). Furthermore, the WHO have also advised against artificial nipples such as
bottle-feeding and pacifier use, as it influences early weaning and development
of malocclusions (Vallenas & Savage, 1998).
It was noted that prolonged breastfeeding can exert a positive effect on the
development of deep bite in the deciduous dentition. This is through satisfying
the urge to suck as well as preventing the occurrence of non-nutritive sucking
habits and possibly stimulating correct tongue position and nose breathing
(Romero et al., 2011). Breastfeeding was concluded to have a protective factor,
stimulating the skeletal and muscular development of the child's face (Kobayashi
88
et al., 2010; Vasconcelos et al., 2011). In the present study, children who were
breast-fed showed tendencies towards normal occlusion development, while
those who were bottle-fed or mixed fed had tendencies to develop a deep bite,
protrusion and AOB. .
It is well established that prolonged durations of non-nutritive sucking habits lead
to malocclusions, specifically AOB in the primary dentition stage (Dos Santos et
al., 2012; Jabbar et al., 2011; Kobayashi et al., 2010; Oliveira et al., 2010;
Romero et al., 2011; Urzal, Braga, & Ferreira, 2013; Urzal et al., 2013;
Vasconcelos et al., 2011). Although, the effect of bottle-feeding remains to be a
controversial factor. Several studies not only suggest the link between the
development of malocclusions but also the type of occlusal alterations to be
associated with bottle-feeding (Charchut et al., 2003; Dos Santos et al., 2012;
Jabbar et al., 2011; Oliveira et al., 2010; Vasconcelos et al., 2011).
In the study by Oliveira et al. (2010) who evaluated the relationship between
determinants and prevalence of malocclusion in children with special needs
demonstrated that the children who had AOB or cross-bite were those whose
mothers stated bottle-feeding for a duration of 24 months or more. These findings
are also documented in the literature, establishing the link between bottle-feeding
and malocclusion (Góis et al., 2008).
It is suggested that the artificial nipples of the feeding bottles are made from a
more rigid material. This can influence the interior of the oral cavity, leading to
malocclusions of teeth and transverse growth of the palate. These are conditions
that results in the development of malocclusions such as posterior cross-bite
89
(Drane, 1996). In the present study, bottle-feeding and mixed-feeding were
shown to have an effect in the development of all malocclusions, however the risk
factors more closely linked to AOB were thumb-sucking and prolonged duration
of thumb-sucking.
5.6 SLEEPING ISSUES
Sleep-disordered breathing (SDB) in children is a very common as well as serious
health problem. This includes mouth-breathing, snoring, obstructive sleep-
apnoea (OSA) to mention a few. Surgical procedures to correct snoring, OSA and
mouth-breathing include tonsillectomy and adenoidectomy which are highly
recommended for paediatric patients, given that the child presents with enlarged
tonsils and/or adenoids (Sabuncuoglu, 2013). In the present study, children who
had snoring or mouth-breathing issues were more likely to develop abnormal
occlusions such as protrusion, deep bite and AOB. Furthermore, children who
had surgical procedures to remove tonsils and/or adenoids were children who
presented with deep bite, protrusion and AOB.
Furthermore, Li et al. (2010) noted that sufficient duration of breastfeeding had a
positive impact in reduction of the risk of habitual snoring in school-aged children.
It is suggested that children who were breastfed for duration of two to five months,
had reductions in sleep-disordered breathing (SDB) (Montgomery-Downs,
Crabtree, Capdevila, & Gozal, 2007). Longer than five months duration of
breastfeeding had little effect on SDB (Montgomery-Downs et al., 2007). In the
present study, children who were breastfed or mixed-fed were least likely to have
stated as having mouth-breathing, snoring or other sleep issues.
90
5.3 LIMITATIONS
A study that was carried out by Sousa, Ribeiro, et al. (2014), 78% of the sample
involved children aged three to four years old, while only 22% were five years old.
The prevalence of AOB in this study was calculated to be 21%. Age and
prolonged use of pacifier and/or thumb-sucking habits were strongly associated
with AOB. In contrast, a study by Ramos-Jorge, Motta, Marques, Paiva, and
Ramos-Jorge (2015), 50.6% of the sample involved children aged five years and
had a 69.9% prevalence of malocclusion in the anterior region. Similarly, there
was high association between non-nutritive sucking habits and AOB. This present
study analyses children in their mixed dentition stage, aged seven to 12 years of
age with a prevalence of 76% for AOB.
It has been suggested that with an increasing age, non-nutritive sucking habits
reduce, as well as parents’ understanding of their child’s limitations as they
mature, becomes simplified. Hence the sampling process identifies the
differences in the results amongst these studies in terms of prevalence of AOB
and non-nutritive sucking habits. It is, however not shown in the present study,
with a higher prevalence percentage than those mentioned above. This can
suggest a lack of cessation of undesirable habits, unfavourable growth factors
associated, varying demographics in terms of region and country. As has been
suggested previously that prolonged duration of non-nutritive sucking habits in
combination with a hyperdivergent facial pattern may lead to a significant risk
factor in AOB malocclusion (Urzal et al., 2013). Furthermore, the majority of
previous literature evaluated children from South America, particularly Brazil and
Venezuela. The difference in ethnicity can play a role in the prevalence rate
across various regions.
91
It is accepted that the tendency of self-correction of the AOB takes place from the
primary to the mixed dentition stage. This can only take place if cessation of
unfavourable habits such as pacifier use, and finger/thumb-sucking takes place
(Dimberg, Lennartsson, Söderfeldt, & Bondemark, 2011; Franco & Gorritxo,
2012; Urzal et al., 2013). Diagnosis of AOB is crucial, due to other dental
anomalies associated with it such as posterior cross-bite and tongue thrust. AOB
will self-correct given habit has ceased before the age of three years (Dimberg et
al., 2011). This will hence prevent structural and myofunctional deviations which
might sustain the morphological malocclusions (Ovsenik et al., 2007).
Educating parents/guardians at an earlier stage is therefore vital. This study also
confirms that for AOB to self-correct, cessation of non-nutritive sucking habits
need to take place. The high prevalence rate shown in the present study can
therefore suggest that there is a possibility the children sampled in the study who
presented with an AOB did not cease habits at an earlier age. Another limitation
includes not evaluating within the questionnaire whether or not the non-nutritive
sucking habit was current on the date the questionnaire was conducted.
Taking into consideration the use of bottle-feeding and its relation to pacifier
and/or thumb-sucking habits (Telles et al., 2009), it is advisable to introduce semi-
solid and solid foods into the child’s dietary intake as soon as the child develops
the primary dentition and has the capacity to perform masticatory movements
(Romero et al., 2011). The present study did not evaluate timeframe of when solid
food was introduced to the child during their infant years.
92
Although the present study is strong, it has some limitations. It was not possible
to compare the findings in this study with the result of similar investigations of the
primary dentition since the majority of studies exclusively investigated the
deciduous dentition, while this study analysed the mixed dentition. Furthermore,
other studies were qualitative in nature (Thilander et al., 2001; Tschill et al., 1997)
and the quantitative assessment of functional malocclusion traits as well as
associated factors were not taken into account. While this study evaluated the
quantitative component of the association between AOB and environmental
determinants such as non-nutritive sucking habits.
Population sample did not reach the targeted sample size and was extracted from
one public primary school in the region. In addition to that, due to ethics, it was
not possible to physically conduct a clinical occlusal assessment of the children
who participated in the study, suggesting that some potential inaccuracy could
have played a role in the influence of results. These include non-expert
assessment of occlusion by parents/guardians rather than a dental practitioner,
assessment using photographs rather than a clinical exam of the child, and
assessment of photographs that either represent the lateral or the frontal aspect
of the mouth and not the overall view of the mouth. Additional studies with
inclusion of a clinical occlusal exam, are required to outline the prevalence, clarify
the aetiology and identify the severity of AOB across different regions of Australia
to establish more descriptive data representative of the Australian population.
5.8 RECOMMENDATIONS
Future recommendations would be to include a larger sample population of
children from different schools (including public and private schools). This sample
93
size may include a bigger age range of children, perhaps assessing children that
are younger with only deciduous dentition to compare to the mixed dentition
stage. These results can then be comparable to studies conducted of deciduous
dentition in different parts of the world to evaluate the prevalence among the
Australian population and how it compares with Asian and South American
sample populations.
Additionally, assessing and comparing different parts of Australia, including
metropolitan, regional and rural demographics would provide results that can be
generalizable to the Australian population. Furthermore, it would be beneficial to
analyse and compare Indigenous children to non-Indigenous children which
would shed more insight on the prevalence and effect of non-nutritive sucking on
AOB that is more accurate and representative of the Australian population.
Another future recommendation includes obtaining ethical approval to carry out
expert assessment and measurements of children’s occlusion by a dental
practitioner which would yield more descriptive results. These could be assessed
by two orthodontic specialists where intra-rater and inter-rater reliability measures
may be conducted to yield more accurate data.
5.9 CONCLUSIONS
In sum, this study reported that the prevalence of AOB (76%) among children
with mixed dentition in Orange, NSW was generally higher than what has been
reported in other parts of the world, including South America and Asia. Insufficient
breastfeeding duration, prolonged duration of thumb-sucking with/without
combining pacifier use all had aetiological association with AOB with the major
94
contributor being over 12-months thumb-sucking commencing between 2 and 5
years of age. Furthermore, sleeping issues such as snoring and mouth-breathing
were highly associated with all malocclusions examined. Children whose parents
had selected secondary or TAFE as their highest level of education were more
likely to develop AOB than those whose parents were of tertiary or post-graduate
levels of education.
In conclusion, the findings of this study suggest the importance of early
awareness and education to parents on non-nutritive sucking behaviours and the
effects it can have on the growth and development of the orofacial structures
leading to abnormal malocclusions. This study can initiate future studies on
prevention and early treatment strategies to correct AOB caused by behavioural
factors.
95
REFERENCES
Ackerman, J. L., & Proffit, W. R. (1969). The characteristics of malocclusion: a modern approach to classification and diagnosis. American Journal of Orthodontics and Dentofacial Orthopedics, 56(5), 443-454.
Adair, S. M., Milano, M., Lorenzo, I., & Russell, C. (1995). Effects of current and former pacifier use on the dentition of 24-to 59-month old children. Pediatric dentistry, 17, 437-444.
Akbari, M., Lankarani, K. B., Honarvar, B., Tabrizi, R., Mirhadi, H., & Moosazadeh, M. (2016). Prevalence of malocclusion among Iranian children: A systematic review and meta-analysis. Dental Research Journal, 13(5), 387-395.
Alonso Chevitarese, A. B., Valle, D. D., & Moreira, T. C. (2003). Prevalence of malocclusion in 4-6 year old Brazilian children. Journal of Clinical Pediatric Dentistry, 27(1), 81-85.
Anderson, A. A. (2007). The dentition and occlusal development in children of African American Descent: Biometrics of the primary dentition. The Angle Orthodontist, 77(3), 421-429.
Angle, E. H. (1899). Classification of malocclusion. Dent Cosmos, 41, 350-375.Philadelphia, Pennsylvania, USA.
Angle, E. H. (1900). Treatment of malocclusion of the teeth and fractures of the maxillae: Angle's system. White Dental Manufacturing Company.
Ayers, F., & Hilton, L. (1976). Treatment of ankyloglossia: report of case. ASDC journal of dentistry for children, 44(3), 237-239.
Baalack, J. B., Frisk, A. K. (1971). Finger sucking in children: a study of incidence and occlusal conditions. Acta Odontol Scand 29:499-512.
Barbre, R. E., & Sinclair, P. M. (1991). A cephalometric evaluation of anterior openbite correction with the magnetic active vertical corrector. The Angle Orthodontist, 61(2), 93-102.
Beane, R. A. (1999). Nonsurgical management of the anterior open bite: a review of the options. Paper presented at the Seminars in orthodontics.
Bell, W. H., & Dann, J. J. (1973). Correction of dentofacial deformities by surgery in the anterior part of the jaws: a study of stability and soft-tissue changes. American journal of orthodontics, 64(2), 162-187.
Benkert, K. (1996). The effectiveness of orofacial myofunctional therapy in improving dental occlusion. The International journal of orofacial myology: official publication of the International Association of Orofacial Myology, 23, 35-46.
Bergersen, E. O. (1988). A longitudinal study of anterior vertical overbite from eight to twenty years of age. The Angle Orthodontist, 58(3), 237-256.
96
Bishara, S. E., & Jakobsen, J. R. (1998). Changes in overbite and face height from 5 to 45 years of age in normal subjects. The Angle Orthodontist, 68(3), 209-216.
Bishara, S. E., Warren, J. J., Broffitt, B., & Levy, S. M. (2006). Changes in the prevalence of nonnutritive sucking patterns in the first 8 years of life. American Journal of Orthodontics and Dentofacial Orthopedics, 130(1), 31-36. doi:https://doi.org/10.1016/j.ajodo.2004.11.033
Björk, A. (1969). Prediction of mandibular growth rotation. American journal of orthodontics, 55(6), 585-599.
Bondemark, L., Holm, A.-K., Hansen, K., Axelsson, S., Mohlin, B., Brattstrom, V., . . . Pietila, T. (2007). Long-term stability of orthodontic treatment and patient satisfaction: a systematic review. The Angle Orthodontist, 77(1), 181-191.
Brammer, J., Finn, R., Bell, W., Sinn, D., Reisch, J., & Dana, K. (1980). Stability after bimaxillary surgery to correct vertical maxillary excess and mandibular deficiency. Journal of oral surgery (American Dental Association: 1965), 38(9), 664.
Burford, D., & Noar, J. (2003). The causes, diagnosis and treatment of anterior open bite. Dental update, 30(5), 235-241.
Cameron, A. C., & Widmer, R. P. (2013). Handbook of pediatric dentistry: Elsevier Health Sciences.
Cangialosi, T. J. (1984). Skeletal morphologic features of anterior open bite. American journal of orthodontics, 85(1), 28-36.
Cardak, B. A., & Ryan, C. (2006). Why are High-Ability Individuals from Poor Backgrounds Under-Represented at University? Available at SSRN 914025.
Cardoso, A. C., Bello, M. G. d., Vellini-Ferreira, F., & Ferreira-Santos, R. I. (2014). Sucking habits and anterior open bite among Venezuelan and Brazilian children. Brazilian Journal of Oral Sciences, 13(3), 219-224.
Carlsen, D. B., & Meredith, H. V. (1960). Biologic variation in selected relationships of opposing posterior teeth. The Angle Orthodontist, 30(3), 162-173.
Carvalho, A., Paiva, S., Scarpelli, A., Viegas, C., Ferreira, F., & Pordeus, I. (2011). Prevalence of malocclusion in primary dentition in a population-based sample of Brazilian preschool children. European journal of paediatric dentistry: official journal of European Academy of Paediatric Dentistry, 12(2), 107-111.
Cassis, M. A., de Almeida, R. R., Janson, G., de Almeida-Pedrin, R. R., & de Almeida, M. R. (2012). Treatment effects of bonded spurs associated with high-pull chincup therapy in the treatment of patients with anterior open bite. American journal of orthodontics and dentofacial orthopedics, 142(4), 487-493. doi:http://dx.doi.org/10.1016/j.ajodo.2012.04.022
Cattell, R. B. (1966). The scree test for the number of factors. Multivariate Behavioural Research, 1, 245-276.
97
Charchut, S. W., Allred, E. N., & Needleman, H. L. (2003). The effects of infant feeding patterns on the occlusion of the primary dentition. Journal of dentistry for children, 70(3), 197-203.
Ciuffolo, F., Manzoli, L., D'attilio, M., Tecco, S., Muratore, F., Festa, F., & Romano, F. (2005). Prevalence and distribution by gender of occlusal characteristics in a sample of Italian secondary school students: a cross-sectional study. The European Journal of Orthodontics, 27(6), 601-606.
Cooke, M. (1980). Anterior open bite. Orthodontic aspects--part 1. Dental update, 7(6), 475.
Corrêa-Faria, P., Ramos-Jorge, M., Martins-Júnior, P., Vieira-Andrade, R., & Marques, L. (2014). Malocclusion in preschool children: prevalence and determinant factors. European Archives of Paediatric Dentistry, 15(2), 89-96.
Corruccini, R. S., & Potter, R. H. Y. (1980). Genetic analysis of occlusal variation in twins. American journal of orthodontics, 78(2), 140-154.
Cozza, P., Baccetti, T., Franchi, L., & McNamara, J. A. (2006). Treatment effects of a modified quad-helix in patients with dentoskeletal open bites. American journal of orthodontics and dentofacial orthopedics, 129(6), 734-739.
Cozza, P., Baccetti, T., Franchi, L., Mucedero, M., & Polimeni, A. (2005). Sucking habits and facial hyperdivergency as risk factors for anterior open bite in the mixed dentition. American Journal of Orthodontics and Dentofacial Orthopedics, 128(4), 517-519.
Cozza, P., Mucedero, M., Baccetti, T., & Franchi, L. (2005). Early orthodontic treatment of skeletal open-bite malocclusion: a systematic review. The Angle Orthodontist, 75(5), 707-713.
da Silva, L. P. M., & Gleiser, R. (2008). Occlusal development between primary and mixed dentitions: a 5-year longitudinal study. Journal of Dentistry for Children, 75(3), 287-294.
Davies, S., & Gray, R. (2001). Occlusion: What is occlusion? British dental journal, 191(5), 235.
Dean, J. A. (2015). McDonald and Avery's Dentistry for the Child and Adolescent-E-book. Elsevier Health Sciences.
De Boer, M. (1976). Sucking of the thumb or fingers. Nederlands tijdschrift voor tandheelkunde, 83(13), 22.
del Conte Zardetto, C. G., Rodrigues, C., & Stefani, F. (2002). Effects of different pacifiers on the primary dentition and oral myofunctional structures of preschool children. Pediatric dentistry, 24(6), 552-580.
del Valle, L. M. L., Dave-Singh, G., Feliciano, N., & Machuca, M. D. C. (2006). Associations between a history of breast feeding, malocclusion and parafunctional habits in Puerto Rican children. Puerto Rico Health Sciences Journal, 25(1).
98
Dellinger, E. L. (1986). A clinical assessment of the active vertical corrector—a nonsurgical alternative for skeletal open bite treatment. American journal of orthodontics, 89(5), 428-436.
Denison, T. F., Kokich, V. G., & Shapiro, P. A. (1989). Stability of maxillary surgery in openbite versus nonopenbite malocclusions. The Angle Orthodontist, 59(1), 5-10.
Dhar, V., Jain, A., Van Dyke, T., & Kohli, A. (2007). Prevalence of gingival diseases, malocclusion and fluorosis in school-going children of rural areas in Udaipur district. Journal of Indian Society of Pedodontics and Preventive Dentistry, 25(2), 103.
Dimberg, L., Lennartsson, B., Söderfeldt, B., & Bondemark, L. (2011). Malocclusions in children at 3 and 7 years of age: a longitudinal study. The European Journal of Orthodontics, 35(1), 131-137.
Dos Santos, R. R., Nayme, J., Garbin, A., Saliba, N., Garbin, C., & Moimaz, S. (2012). Prevalence of malocclusion and related oral habits in 5-to 6-year-old children. Oral Health Prev Dent, 10(4), 311-318.
Drane, D. (1996). The effect of use of dummies and teats on orofacial development. Breastfeeding review, 4(2), 59.
Dung, D. J., & Smith, R. J. (1988). Cephalometric and clinical diagnoses of open bite tendency. American journal of orthodontics and dentofacial orthopedics, 94(6), 484-490.
Ellis, E., & McNamara, J. A. (1984). Components of adult Class III open-bite malocclusion. American journal of orthodontics, 86(4), 277-290.
English, J. D. (2002). Early treatment of skeletal open bite malocclusions. American Journal of Orthodontics and Dentofacial Orthopedics, 121(6), 563-565.
Epker, B. N., & Fish, L. C. (1977). Surgical-orthodontic correction of open-bite deformity. American journal of orthodontics, 71(3), 278-299.
Facciolli Hebling, S. R., Cortellazzi, K. L., Silva Tagliaferro, E. P. d., Hebling, E., Bovi Ambrosano, G. M., Castro Meneghim, M. d., & Pereira, A. C. (2008). Relationship between malocclusion and behavioral, demographic and socioeconomic variables: a cross-sectional study of 5-year-olds. Journal of Clinical Pediatric Dentistry, 33(1), 75-79.
Farsi, N. M., Salama, F., & Pedo, C. (1997). Sucking habits in Saudi children: prevalence, contributing factors and effects on the primary dentition. Pediatric dentistry, 19, 28-33.
Fletcher, S. G., Casteel, R. L., & Bradley, D. P. (1961). Tongue-thrust swallow, speech articulation, and age. Journal of Speech and Hearing Disorders, 26(3), 201-208.
Foltz, A. T. (1987). The influence of cancer on self-concept and life quality. Paper presented at the Seminars in Oncology Nursing.
99
Foster, T., & Hamilton, M. (1969). Occlusion in the primary dentition. Study of children at 2 and one-half to 3 years of age. British dental journal, 126(2), 76.
Franco, V. V., & Gorritxo, B. G. (2012). Pacifier sucking habit and associated dental changes. Importance of early diagnosis. Paper presented at the Anales de pediatria (Barcelona, Spain: 2003).
Frazão, P., Narvai, P. C., Latorre, M. d. R. D. d., & Castellanos, R. A. (2004). Are severe occlusal problems more frequent in permanent than deciduous dentition? Revista de saude Publica, 38, 247-254.
Friel, S. (1927). Occlusion. Observations on its development from infancy to old age. International Journal of Orthodontia, Oral Surgery and Radiography, 13(4), 322-343.
Frost, D. E., Fonseca, R. J., Turvey, T. A., & Hall, D. J. (1980). Cephalometric diagnosis and surgical-orthodontic correction of apertognathia. American journal of orthodontics, 78(6), 657-669.
Fujiki, T., Inoue, M., Miyawaki, S., Nagasaki, T., Tanimoto, K., & Takano-Yamamoto, T. (2004). Relationship between maxillofacial morphology and deglutitive tongue movement in patients with anterior open bite. American journal of orthodontics and dentofacial orthopedics, 125(2), 160-167.
Galán-Gónzalez, A. F., Aznar-Martin, T., Cabrera-Dominguez, M. E., & Dominguez-Reyes, A. (2014). Do breastfeeding and bottle feeding influence occlusal parameters? Breastfeeding Medicine, 9(1), 24-28.
Ganesh, M., Tandon, S., & Sajida, B. (2005). Prolonged feeding practice and its effects on developing dentition. Journal of Indian Society of Pedodontics and Preventive Dentistry, 23(3), 141.
Gelgör, İ. E., Karaman, A. İ., & Ercan, E. (2007). Prevalence of malocclusion among adolescents in central anatolia. European journal of dentistry, 1(3), 125.
Giuntini, V., Franchi, L., Baccetti, T., Mucedero, M., & Cozza, P. (2008). Dentoskeletal changes associated with fixed and removable appliances with a crib in open-bite patients in the mixed dentition. American journal of orthodontics and dentofacial orthopedics, 133(1), 77-80.
Góis, E. G. O., Ribeiro-Júnior, H. C., Vale, M. P. P., Paiva, S. M., Serra-Negra, J. M. C., Ramos-Jorge, M. L., & Pordeus, I. A. (2008). Influence of nonnutritive sucking habits, breathing pattern and adenoid size on the development of malocclusion. The Angle Orthodontist, 78(4), 647-654.
Grabowski, R., Stahl, F., Gaebel, M., & Kundt, G. (2007). Relationship between occlusal findings and orofacial myofunctional status in primary and mixed dentition. Journal of Orofacial Orthopedics/Fortschritte der Kieferorthopädie, 68(1), 26-37.
Gray, R. (2004). Occlusion and Clinical Practice—An Evidence Based Approach. British Dental Journal, 197(2), 107-107.
100
Greenlee, G. M., Huang, G. J., Chen, S. S.-H., Chen, J., Koepsell, T., & Hujoel, P. (2011). Stability of treatment for anterior open-bite malocclusion: a meta-analysis. American Journal of Orthodontics and Dentofacial Orthopedics, 139(2), 154-169.
Haralabakis, N., & Papadakis, G. (2005). Relapse after orthodontics and orthognathic surgery. World journal of orthodontics, 6(2).
Haryett, R., Hansen, F., & Davidson, P. (1970). Chronic thumb-sucking: a second report on treatment and its psychological effects. American journal of orthodontics, 57(2), 164-178.
Haryett, R., Hansen, F., Davidson, P., & Sandilands, M. L. (1967). Chronic thumb-sucking: the psychologic effects and the relative effectiveness of various methods of treatment. American journal of orthodontics, 53(8), 569-585.
Haymond, C. S., Stoelinga, P. J., Blijdorp, P. A., Leenen, R. J., & Merkens, N. M. (1991). Surgical orthodontic treatment of anterior skeletal open bite using small plate internal fixation: One to five year follow-up. International journal of oral and maxillofacial surgery, 20(4), 223-227.
Heimer, M. V., Tornisiello Katz, C. R., & Rosenblatt, A. (2008). Non-nutritive sucking habits, dental malocclusions, and facial morphology in Brazilian children: a longitudinal study. The European Journal of Orthodontics, 30(6), 580-585.
Helland, M. M. (1980). Anatomy and function of the temporomandibular joint. Journal of Orthopaedic & Sports Physical Therapy, 1(3), 145-152.
Helle, A., & Haavikko, K. (1974). Prevalence of earlier sucking habits revealed by anamnestic data and their consequences for occlusion at the age of eleven. Proceedings of the Finnish Dental Society. Suomen Hammaslaakariseuran toimituksia, 70(5), 191.
Hellman, M. (1931). Open-bite. International Journal of Orthodontia, Oral Surgery and Radiography, 17(5), 421-444.
Helm, S. (1968). Malocclusion in Danish children with adolescent dentition: an epidemiologic study. American journal of orthodontics, 54(5), 352-366.
Hiranaka, D. K., & Kelly, J. (1986). Stability of simultaneous orthognathic surgery on the maxilla and mandible: a computer-assisted cephalometric study. The International journal of adult orthodontics and orthognathic surgery, 2(4), 193-213.
Hoppenreijs, T., Hakman, E., Hof van't, M., Stoelinga, P., Tuinzing, D., & Freihofer, H. (1999). Psychologic implications of surgical-orthodontic treatment in patients with anterior open bite. The International journal of adult orthodontics and orthognathic surgery, 14(2), 101-112.
Huang, B., Lejarraga, C., Franco, C. S., Kang, Y., Lee, A., Abbott, J., . . .
Pumtang‐on, P. (2015). Influence of non‐orthodontic intervention on digit
sucking and consequent anterior open bite: a preliminary study. International dental journal, 65(5), 235-241.
101
Huang, G. J., Justus, R., Kennedy, D. B., & Kokich, V. G. (1990). Stability of anterior openbite treated with crib therapy. The Angle Orthodontist, 60(1), 17-24.
Humphreys, H. (1950). A survey of anteroposterior abnormalities of the jaws in children between the ages of two and five and a half years of age. Brit. Dent. J., 88, 3-15.
Infante, P. (1976). An epidemiologic study of finger habits in preschool children, as related to malocclusion, socioeconomic status, race, sex, and size of community. ASDC journal of dentistry for children, 43(1), 33.
Infante, P. F. (1975). Malocclusion in the deciduous dentition in white, black, and Apache Indian children. The Angle Orthodontist, 45(3), 213-218.
Jabbar, N. S. A., Bueno, A. B. M., Silva, P. E. d., Scavone-Junior, H., & Inês Ferreira, R. (2011). Bottle feeding, increased overjet and Class 2 primary canine relationship: is there any association? Brazilian oral research, 25(4), 331-337.
James, R. (2000). Socioeconomic background and higher education participation: An analysis of school students’ aspirations and expectations. Canberra, Australia: Department of Education, Science and Training.
Järvinen, S., & Lehtinen, L. (1977). Malocclusion in 3-year-old Finnish children. Prevalence and need for treatment. Proceedings of the Finnish Dental Society. Suomen Hammaslaakariseuran toimituksia, 73(4), 162.
Johannsdottir, B., Wisth, P. J., & Magnusson, T. E. (1997). Prevalence of malocclusion in 6-year-old Icelandic children: a study using plaster models and orthopantomograms. Acta Odontologica Scandinavica, 55(6), 398-402.
Johnson, E., & Larson, B. (1993). Thumb-sucking: literature review. ASDC journal of dentistry for children, 60(4), 385-391.
Justus, R. (2001). Correction of anterior open bite with spurs: long-term stability. World J Orthod, 2(3), 219-231.
Katz, C. R. T., Rosenblatt, A., & Gondim, P. P. C. (2004). Nonnutritive sucking habits in Brazilian children: effects on deciduous dentition and relationship with facial morphology. American Journal of Orthodontics and Dentofacial Orthopedics, 126(1), 53-57.
Katz, M. R., Rodin, G., & Devins, G. M. (1995). Self-esteem and cancer: Theory and research. The Canadian Journal of Psychiatry, 40(10), 608-615.
Kawakami, M., Yamamoto, K., Noshi, T., Miyawaki, S., & Kirita, T. (2004). Effect of surgical reduction of the tongue on dentofacial structure following mandibular setback. Journal of oral and maxillofacial surgery, 62(10), 1188-1192.
Kerosuo, H., Laine, T., Nyyssonen, V., & Honkala, E. (1991). Occlusal characteristics in groups of Tanzanian and Finnish urban schoolchildren. The Angle Orthodontist, 61(1), 49-56.
102
Kharbanda, O., Sidhu, S., Shukla, D., & Sundaram, K. (1994). A study of the etiological factors associated with the development of malocclusion. The Journal of clinical pediatric dentistry, 18(2), 95-98.
Kim, D.-h., & Sung, S.-j. (2018). Nonsurgical correction of a Class III skeletal anterior open-bite malocclusion using multiple microscrew implants and digital profile prediction. American Journal of Orthodontics and Dentofacial Orthopedics, 154(2), 283-293.
Klineberg, I., & Jagger, R. (2004). Occlusion and clinical practice. An evidence-based approach, 83-91.
Klocke, A., Nanda, R. S., & Kahl-Nieke, B. (2002). Anterior open bite in the deciduous dentition: longitudinal follow-up and craniofacial growth considerations. American Journal of Orthodontics and Dentofacial Orthopedics, 122(4), 353-358.
Kobayashi, H. M., Scavone Jr, H., Ferreira, R. I., & Garib, D. G. (2010). Relationship between breastfeeding duration and prevalence of posterior crossbite in the deciduous dentition. American Journal of Orthodontics and Dentofacial Orthopedics, 137(1), 54-58.
Koch, G., & Poulsen, S. (2009). Pediatric dentistry: a clinical approach: John Wiley & Sons. 83-84, 296. Copenhagen, Denmark.
Kramer, M. S., Barr, R. G., Dagenais, S., Yang, H., Jones, P., Ciofani, L., & Jané, F. (2001). Pacifier use, early weaning, and cry/fuss behavior: a randomized controlled trial. Jama, 286(3), 322-326.
Kramer, M. S., & Kakuma, R. (2012). Optimal duration of exclusive breastfeeding. Cochrane database of systematic reviews(8).
Larsson, E. (1978). Dummy-and finger-sucking habits with special attention to their significance for facial growth and occlusion. 7. The effect of earlier dummy-and finger-sucking habit in 16-year-old children compared with children without earlier sucking habit. Swedish dental journal, 2(1), 23.
Larsson, E. (1983). Prevalence of crossbite among children with prolonged dummy-and finger-sucking habit. Swedish dental journal, 7(3), 115-119.
Larsson, E. (1985). The prevalence and aetiology of prolonged dummy and finger-sucking habits. The European Journal of Orthodontics, 7(3), 172-176.
Larsson, E. (1986). The effect of dummy-sucking on the occlusion: a review. The European Journal of Orthodontics, 8(2), 127-130.
Larsson, E. F., & Dahlin, K. G. (1985). The prevalence and the etiology of the initial dummy-and finger-sucking habit. American journal of orthodontics, 87(5), 432-435.
Lawry, D. M., Heggie, A. A., Crawford, E. C., & Ruljancich, M. (1990). A review of the management of anterior open bite malocclusion. Australian orthodontic journal, 11(3), 147.
103
Leighton, B. (1977). Early recognition of normal occlusion. Contributions to the biology of occlusal development. Craniofacial growth series. Ann Arbor: University of Michigan. p, 147-167.
Lewis, S. J., & Lehman, I. A. (1929). Observations on growth changes of the teeth and dental arches.The Dental Cosms, Vol. 71, p. 480.
Li, S., Jin, X., Yan, C., Wu, S., Jiang, F., & Shen, X. (2010). Habitual snoring in school-aged children: environmental and biological predictors. Respiratory research, 11(1), 144.
Lin, L.-H., Huang, G.-W., & Chen, C.-S. (2013). Etiology and treatment modalities of anterior open bite malocclusion. Journal of Experimental & Clinical Medicine, 5(1), 1-4.
Lindner, A., & Modѐer, T. (1989). Relation between sucking habits and dental
characteristics in preschoolchildren with unilateral cross‐bite. European Journal
of Oral Sciences, 97(3), 278-283.
Lochib, S., Indushekar, K., Saraf, B. G., Sheoran, N., & Sardana, D. (2015). Occlusal characteristics and prevalence of associated dental anomalies in the primary dentition. Journal of epidemiology and global health, 5(2), 151-157.
Lopez-Gavito, G., Wallen, T. R., Little, R. M., & Joondeph, D. R. (1985). Anterior open-bite malocclusion: a longitudinal 10-year postretention evaluation of orthodontically treated patients. American journal of orthodontics, 87(3), 175-186.
Macena, M. C. B., Katz, C. R. T., & Rosenblatt, A. (2009). Prevalence of a posterior crossbite and sucking habits in Brazilian children aged 18–59 months. The European Journal of Orthodontics, 31(4), 357-361.
Machado, D. B., Brizon, V. S. C., Ambrosano, G. M. B., Madureira, D. F., Gomes, V. E., & Oliveira, A. C. B. d. (2014). Factors associated with the prevalence of anterior open bite among preschool children: A population-based study in Brazil. Dental press journal of orthodontics, 19(5), 103-109.
Marks, G. N., Cresswell, J., & Ainley, J. (2006). Explaining socioeconomic inequalities in student achievement: The role of home and school factors. Educational research and Evaluation, 12(02), 105-128.
Marques, L. S., Barbosa, C. C., Ramos-Jorge, M. L., Pordeus, I. A., & Paiva, S. M. (2005). Malocclusion prevalence and orthodontic treatment need in 10-14-year-old schoolchildren in Belo Horizonte, Minas Gerais State, Brazil: a psychosocial focus. Cadernos de saude publica, 21(4), 1099-1106.
McDonald, R. E., Avery, D. R., Stookey, G. K., Chin, J. R., & Kowolik, J. E. (2011). Dental caries in the child and adolescent. Paper presented at the Elsevier Inc.
McMillan, J., & Western, J. (2000). Measurement of the socio-economic status of Australian higher education students. Higher Education, 39(2), 223-247.
McNeill, C. (1997). Science and practice of occlusion: Quintessence Publishing (IL). Chicago, ILL, USA.
104
McRae, E. J. (2010). Bondable lingual spur therapy to treat anterior open bite.
Melsen, B., Stensgaard, K., & Pedersen, J. (1979). Sucking habits and their influence on swallowing pattern and prevalence of malocclusion. The European Journal of Orthodontics, 1(4), 271-280.
Meyer-Marcotty, P., Hartmann, J., & Stellzig-Eisenhauer, A. (2007). Dentoalveolar open bite treatment with spur appliances. Journal of Orofacial Orthopedics/Fortschritte der Kieferorthopädie, 68(6), 510-521.
Miyawaki, S., Oya, S., Noguchi, H., & Takano-Yamamoto, T. (2000). Long-term changes in dentoskeletal pattern in a case with Beckwith-Wiedemann syndrome following tongue reduction and orthodontic treatment. The Angle Orthodontist, 70(4), 326-331.
Modёer, T., Odenrtck, L., & Lindner, A.,. (1982). Sucking habits and their relation
to posterior cross‐bite in 4‐year‐old children. European Journal of Oral
Sciences, 90(4), 323-328.
Mohl, N. (1988). Introduction to occlusion. A textbook of occlusion, 15-23. Quintessence Publishing, Chicago, ILL, USA.
Mohlin, B., & Kurol, J. (2002). To what extent do deviations from an ideal occlusion constitute a health risk? Swedish dental journal, 27(1), 1-10.
Montgomery-Downs, H. E., Crabtree, V. M., Capdevila, O. S., & Gozal, D. (2007). Infant-feeding methods and childhood sleep-disordered breathing. Pediatrics, 120(5), 1030-1035.
Moss, M. L., & Salentijn, L. (1971). Differences between the functional matrices in anterior open-bite and in deep overbite. American journal of orthodontics, 60(3), 264-280.
Moyers, R. (1973). Maturation of orofacial musculature, Handbook of Orthodontics, 3rd Edit. Year Book Medical Publishers Co., Chicago, 135-137.
Narbutyte, I., Narbutyte, A., & Linkeviciene, L. (2013). Relationship between breastfeeding, bottle-feeding and development of malocclusion. Stomatologija, 15(3), 67-72.
Ng, C. S. T., Wong, W. K. R., & Hagg, U. (2008). Orthodontic treatment of anterior open bite. International Journal of Paediatric Dentistry, 18(2), 78-83.
Ngan, P., & Fields, H. (1996). Open bite: a review of etiology and management. Pediatric dentistry, 19(2), 91-98.
Nogueira, F. F., Mota, L. M., Nouer, P. R. A., & Nouer, D. F. (2005). Nogueira® lingual bonded spur: supporting treatment of atypical swallow by lingual pressure. Revista Dental Press de Ortodontia e Ortopedia Facial, 10(2), 129-156.
Northway, W. M., Wainright, R. L., & Demirjian, A. (1984). Effects of premature loss of deciduous molars. The Angle Orthodontist, 54(4), 295-329.
105
Aidsman, I. K. (1977). Glossary of prosthodontic terms. The Journal of prosthetic dentistry, 38(1), 66-109. Chicago, ILL, USA.
Øgaard, B., Larsson, E., & Lindsten, R. (1994). The effect of sucking habits, cohort, sex, intercanine arch widths, and breast or bottle feeding on posterior crossbite in Norwegian and Swedish 3-year-old children. American Journal of Orthodontics and Dentofacial Orthopedics, 106(2), 161-166.
Okeson, J. P. (2014). Management of temporomandibular disorders and occlusion: Elsevier Health Sciences.Lexington, Kentucky, USA.
Oliveira, A. C., Pordeus, I. A., Torres, C. S., Martins, M. T., & Paiva, S. M. (2010). Feeding and nonnutritive sucking habits and prevalence of open bite and crossbite in children/adolescents with Down syndrome. The Angle Orthodontist, 80(4), 748-753.
Onyeaso, C. (2003). An assessment of relationship between self‐esteem,
orthodontic concern, and Dental Aesthetic Index (DAI) scores among secondary school students in Ibadan, Nigeria. International dental journal, 53(2), 79-84.
Onyeaso, C. O. (2004). Prevalence of malocclusion among adolescents in Ibadan, Nigeria. American Journal of Orthodontics and Dentofacial Orthopedics, 126(5), 604-607.
Otuyemi, O., & Abidoye, R. (1993). Malocclusion in 12-year-old suburban and rural Nigerian children. Community dental health, 10(4), 375-380.
Ovsenik, M. (2009). Incorrect orofacial functions until 5 years of age and their association with posterior crossbite. American Journal of Orthodontics and Dentofacial Orthopedics, 136(3), 375-381.
Ovsenik, M., Farčnik, F. M., Korpar, M., & Verdenik, I. (2007). Follow-up study of functional and morphological malocclusion trait changes from 3 to 12 years of age. The European Journal of Orthodontics, 29(5), 523-529.
Parker, J. H. (1971). The interception of the open bite in the early growth period. The Angle Orthodontist, 41(1), 24-44.
Paunio, P., Rautava, P., & Sillanpää, M. (1993). The Finnish Family Competence Study: the effects of living conditions on sucking habits in 3-year-old Finnish children and the association between these habits and dental occlusion. Acta Odontologica Scandinavica, 51(1), 23-29.
Perera, I., Kruger, E., & Tennant, M. (2010). Rural public dental clinic distribution in three states of Australia: using spatial analysis to inform management and planning of services. Asia Pacific Journal of Health Management, 5(1), 40.
Peres, K. G., Barros, A. J., Peres, M. A., & Victora, C. G. (2007). Effects of breastfeeding and sucking habits on malocclusion in a birth cohort study. Revista de saude Publica, 41(3), 343-350.
Peres, K. G., De Oliveira Latorre, M. D. R. D., Sheiham, A., Peres, M. A., Victora, C. G., & Barros, F. C. (2007). Social and biological early life influences on the
106
prevalence of open bite in Brazilian 6‐year‐olds. International journal of
paediatric dentistry, 17(1), 41-49.
Popovich, F., & Thompson, G. W. (1973). Thumb-and finger-sucking: Its relation to malocclusion. American journal of orthodontics, 63(2), 148-155.
Proffit, W. R., Fields, H. W., & Sarver, D. M. (2014). Contemporary Orthodontics-E-Book: Elsevier Health Sciences.St Louis, Missouri, USA.
Ramfjord, S. P., & Ash, M. M. (1966). Occlusion: WB Saunders Company.Philadelphia, Pennsylvania, USA.
Ramos-Jorge, J., Motta, T., Marques, L. S., Paiva, S. M., & Ramos-Jorge, M. L. (2015). Association between anterior open bite and impact on quality of life of preschool children. Brazilian oral research, 29(1), 1-7.
Ravn, J. (1974). The prevalence of dummy and finger sucking habits in Copenhagen children until the age of 3 years. Community dentistry and oral epidemiology, 2(6), 316-322.
Ravn, J. (1975). Occlusion in the primary dentition in 3‐year‐old children.
European Journal of Oral Sciences, 83(3), 123-130.
Ravn, J. (1976). Sucking habits and occlusion in 3‐year‐old children. European
Journal of Oral Sciences, 84(4), 204-209.
Reynoso, M., Hernandez, A., Lizcano-Gil, L., Sarralde, A., Abreu, M., Nazara, Z., & Fragoso, R. (1993). Autosomal dominant congenital macroglossia: further delineation of the syndrome. Genetic counseling (Geneva, Switzerland), 5(2), 151-154.
Ricketts, R. M. (1969). Occlusion—the medium of dentistry. The Journal of prosthetic dentistry, 21(1), 39-60.
Rogers, A. P. (1927). Open-bite cases involving tongue habits. International Journal of Orthodontia, Oral Surgery and Radiography, 13(10), 837-844.
Romero, C. C., Scavone-Junior, H., Garib, D. G., Cotrim-Ferreira, F. A., & Ferreira, R. I. (2011). Breastfeeding and non-nutritive sucking patterns related to the prevalence of anterior open bite in primary dentition. Journal of Applied Oral Science, 19(2), 161-168.
Sabuncuoglu, O. (2013). Understanding the relationships between breastfeeding, malocclusion, ADHD, sleep-disordered breathing and traumatic dental injuries. Medical hypotheses, 80(3), 315-320.
Sandler, P. J., Madahar, A. K., & Murra, A. (2011). Anterior open bite: aetiology and management. Dental update, 38(8), 522-532.
Sanin, C., & Savara, B. S. (1972). The development of an excellent occlusion. American journal of orthodontics, 61(4), 345-352.
Sassouni, V. (1969). A classification of skeletal facial types. American journal of orthodontics, 55(2), 109-123.
107
Scavone-Junior, H., Ferreira, R. I., Mendes, T. E., & Ferreira, F. V. (2007). Prevalence of posterior crossbite among pacifier users: a study in the deciduous dentition. Brazilian oral research, 21(2), 153-158.
Shapiro, P. A. (2002). Stability of open bite treatment. American journal of orthodontics and dentofacial orthopedics, 121(6), 566-568.
Silva, R. G., & Kang, D. S. (2001). Prevalence of malocclusion among Latino adolescents. American Journal of Orthodontics and Dentofacial Orthopedics, 119(3), 313-315.
Smithpeter, J., & Covell, D. (2010). Relapse of anterior open bites treated with orthodontic appliances with and without orofacial myofunctional therapy. American journal of orthodontics and dentofacial orthopedics, 137(5), 605-614.
Sousa, R. L. d. S., Lima, R. B. d., Florêncio Filho, C., Lima, K. C. d., & Diógenes, A. M. d. N. (2007). Prevalence and risk factors of anterior open bite in the complete deciduous dentition in pre-scholars´ children who live in the city of Natal/RN. Revista Dental Press de Ortodontia e Ortopedia Facial, 12(2), 129-138.
Sousa, R. V. d., Pinto-Monteiro, A. K. d. A., Martins, C. C., Granville-Garcia, A. F., & Paiva, S. M. (2014). Malocclusion and socioeconomic indicators in primary dentition. Brazilian oral research, 28(1), 54-60.
Sousa, R. V. d., Ribeiro, G. L. A., Firmino, R. T., Martins, C. C., Granville-Garcia, A. F., & Paiva, S. M. (2014). Prevalence and associated factors for the development of anterior open bite and posterior crossbite in the primary dentition. Brazilian dental journal, 25(4), 336-342.
Spencer, A. J. (2004). Narrowing the inequality gap in oral health and dental care in Australia: Australian Health Policy Institute at the University of Sydney.
Spencer, J., & Harford, J. (2007). Inequality in oral health in Australia. Australian Review of Public Affairs. Adelaide, SA, Australia.
Stahl, F., Grabowski, R., Gaebel, M., & Kundt, G. (2007). Relationship between occlusal findings and orofacial myofunctional status in primary and mixed dentition. Journal of Orofacial Orthopedics/Fortschritte der Kieferorthopädie, 68(2), 74-90.
Steele, L., Pacza, T., & Tennant, M. (2000). Rural and remote oral health, problems and models for improvement: a Western Australian perspective. Australian Journal of Rural Health, 8(1), 22-28.
Straub, W. J. (1960). Malfunction of the tongue: Part I. The abnormal swallowing habit: Its cause, effects, and results in relation to orthodontic treatment and speech therapy. American journal of orthodontics, 46(6), 404-424.
Straub, W. J. (1961). Malfunction of the tongue: Part II. The abnormal swallowing habit: Its causes, effects, and results in relation to orthodontic treatment and speech therapy. American journal of orthodontics, 47(8), 596-617.
108
Straub, W. J. (1962). Malfunction of the tongue Part III. American journal of orthodontics, 48(7), 486-503.
Subtelny, J. D., & Sakuda, M. (1964). Open-bite: diagnosis and treatment. American journal of orthodontics, 50(5), 337-358.
Subtelny, J. D., & Subtelny, J. D. (1973). Oral habits--studies in form, function, and therapy. The Angle Orthodontist, 43(4), 347-383.
Svedmyr, B. (1979). Dummy sucking. A study of its prevalence, duration and malocclusion consequences. Swedish dental journal, 3(6), 205-210.
Swinehart, E. W. (1942). A clinical study of open-bite. American Journal of Orthodontics and Oral Surgery, 28(1), 18-34.
Swinnen, K., Politis, C., Willems, G., De Bruyne, I., Fieuws, S., Heidbuchel, K., .
. . Carels, C. (2001). Skeletal and dento‐alveolar stability after surgical‐orthodontic treatment of anterior open bite: a retrospective study. The European Journal of Orthodontics, 23(5), 547-557.
Tabachnick, B. G., & Fidell, L. S. (2001). Using multivariate statistics (4th ed.) Needham Heights., MA: Pearson.
Taylor, R. G., Mills, P. B., & Brenner, L. D. (1967). Maxillary and mandibular subapical osteotomies for the correction of anterior open-bite. Oral Surgery, Oral Medicine, Oral Pathology, 23(2), 141-147.
Telles, F. B. d. A., Ferreira, R. I., Magalhães, L. d. N. C., & Scavone-Junior, H. (2009). Effect of breast-and bottle-feeding duration on the age of pacifier use persistence. Brazilian oral research, 23(4), 432-438.
Thilander, B., & Myrberg, N. (1973). The prevalence of malocclusion in Swedish schoolchildren. European Journal of Oral Sciences, 81(1), 12-20.
Thilander, B., Pena, L., Infante, C., Parada, S. S., & de Mayorga, C. (2001). Prevalence of malocclusion and orthodontic treatment need in children and adolescents in Bogota, Colombia. An epidemiological study related to different stages of dental development. European journal of orthodontics, 23(2), 153-168.
Todor, B. I., Vaida, L., Csep, A., & Iurcov, R. (2015). Impact of socio-economic status on malocclusions prevalence to school-children from Western Romania; ethnical disparities. Human and Veterinary Medicine, 7(3), 155-161.
Togawa, R., Iino, S., & Miyawaki, S. (2010). Skeletal Class III and open bite treated with bilateral sagittal split osteotomy and molar intrusion using titanium screws. The Angle Orthodontist, 80(6), 1176-1184.
Tornisiello Katz, C. R., & Rosenblatt, A. (2005). Nonnutritive sucking habits and anterior open bite in Brazilian children: a longitudinal study. Pediatric dentistry, 27(5), 369-373.
Torres, F., Almeida, R. R., De Almeida, M. R., Almeida-Pedrin, R. R., Pedrin, F., & Henriques, J. F. (2006). Anterior open bite treated with a palatal crib and high-
109
pull chin cup therapy. A prospective randomized study. The European Journal of Orthodontics, 28(6), 610-617.
Tschill, P., Bacon, W., & Sonko, A. (1997). Malocclusion in the deciduous dentition of Caucasian children. European journal of orthodontics, 19(4), 361-367.
Türp, J., Greene, C., & Strub, J. (2008). Dental occlusion: a critical reflection on past, present and future concepts. Journal of oral rehabilitation, 35(6), 446-453.
Urzal, V., Braga, A., & Ferreira, A. (2013). Oral habits as risk factors for anterior open bite in the deciduous and mixed dentition-cross-sectional study. European journal of paediatric dentistry: official journal of European Academy of Paediatric Dentistry, 14(4), 299-302.
Urzal, V., Braga, A. C., & Ferreira, A. P. (2013). The prevalence of anterior open bite in Portuguese children during deciduous and mixed dentition–Correlations for a prevention strategy. International orthodontics, 11(1), 93-103.
Vaden, J. L., & Pearson, L. E. (2002). Diagnosis of the vertical dimension. Paper presented at the Seminars in Orthodontics.
Van Dyck, C., Dekeyser, A., Vantricht, E., Manders, E., Goeleven, A., Fieuws, S., & Willems, G. (2016). The effect of orofacial myofunctional treatment in children with anterior open bite and tongue dysfunction: a pilot study. The European Journal of Orthodontics, 38(3), 227-234.
Vasconcelos, F. M. N. d., Massoni, A. C. d. L. T., Heimer, M. V., Ferreira, A. M. B., Katz, C. R. T., & Rosenblatt, A. (2011). Non-nutritive sucking habits, anterior open bite and associated factors in Brazilian children aged 30-59 months. Brazilian dental journal, 22(2), 140-145.
Vig, K. W., & Fields, H. W. (2000). Facial growth and management of orthodontic problems. Pediatric Clinics of North America, 47(5), 1085-1123.
Viggiano, D., Fasano, D., Monaco, G., & Strohmenger, L. (2004). Breast feeding, bottle feeding, and non-nutritive sucking; effects on occlusion in deciduous dentition. Archives of disease in childhood, 89(12), 1121-1123.
Villa, N. L., & Cisneros, G. J. (1996). Changes in the dentition secondary to palatal crib therapy in digit-suckers: a preliminary study. Pediatric dentistry, 19(5), 323-326.
Vu, C. Q., Roberts, W. E., Hartsfield, J. K., & Ofner, S. (2008). Treatment complexity index for assessing the relationship of treatment duration and outcomes in a graduate orthodontics clinic. American journal of orthodontics and dentofacial orthopedics, 133(1), 9. e1-9. e13.
Ward, M. M., Malone, S. H. D., Jann, G. R., & Jann, H. W. (1961). Articulation variations associated with visceral swallowing and malocclusion. Journal of Speech and Hearing Disorders, 26(4), 334-341.
110
Warren, J. J., & Bishara, S. E. (2002). Duration of nutritive and nonnutritive sucking behaviors and their effects on the dental arches in the primary dentition. American Journal of Orthodontics and Dentofacial Orthopedics, 121(4), 347-356.
Warren, J. J., Bishara, S. E., Steinbock, K. L., Yonezu, T., & Nowak, A. J. (2001). Effects of oral habits' duration on dental characteristics in the primary dentition. The Journal of the american dental association, 132(12), 1685-1693.
Warren, J. J., Levy, S. M., Nowak, A. J., & Tang, S. (2000). Non-nutritive sucking behaviors in preschool children: a longitudinal study. Pediatric dentistry, 22(3), 187-191.
Wassell, R. W., Naru, A., Steele, J., & Nohl, F. (2008). Applied occlusion: Quintessentials of Dental Practice.
Washburn, H. (1925). History and evolution of the study of occlusion. Dent Cosmos, 67, 223-237,331.
Watson, W. G. (1981). Open-bite—a multifactorial event. American journal of orthodontics, 80(4), 443-446.
World Health Organization. (2011). Statement: Exclusive breastfeeding for six months best for babies everywhere. World Health Organization, Geneva. Retrieved from http://www. who. int/en.
Worms, F. W., Meskin, L. H., & Isaacson, R. J. (1971). Open-bite. American journal of orthodontics, 59(6), 589-595.
Yousefzadeh, F., Shcherbatyy, V., King, G. J., Huang, G. J., & Liu, Z.-J. (2010). Cephalometric and electromyographic study of patients of East African ethnicity with and without anterior open bite. American Journal of Orthodontics and Dentofacial Orthopedics, 137(2), 236-246.
Zuroff, J. P., Chen, S.-H., Shapiro, P. A., Little, R. M., Joondeph, D. R., & Huang, G. J. (2010). Orthodontic treatment of anterior open-bite malocclusion: stability 10 years postretention. American journal of orthodontics and dentofacial orthopedics, 137(3), 302. e301-302. e308.
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APPENDICES
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Appendix I. Information sheet to prospective parents/guardian and to child.
PARTICIPANT INFORMATION SHEET (Parent/Guardian)
Prevalence and determinants of Non-Nutritive Sucking on Anterior Open
Bite in Children Attending Primary School
Chief researcher:
Liyana Tanny
Postgraduate student and Oral Health Therapist
Project Supervisors:
o Professor Boyen Huang –Head of School, School of Dentistry and Health
Sciences, Charles Sturt University, President-elect of IADR Australian and
New Zealand Division
Expertise: Paediatric dentistry, and health care
administration
o Dr Geoffrey Currie – Associate Professor, School of Dentistry and Health
Sciences, Charles Sturt University
Expertise: Medical Radiation, clinical trial and statistics
o Dr Ashraf Shaweesh – Lecturer in Oral Health, School of Dentistry and
Health Sciences, Charles Sturt University
Expertise: Head and neck anatomy
Invitation
You are invited to participate in a research study on assessing prevalence and
effects of non-nutritive sucking on anterior open bite in children aged 7-12 years.
The study is being conducted by Liyana Tanny, an Oral Health Therapist and
current Postgraduate student in the School of Dentistry & Health Sciences at
Charles Sturt University.
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Before you decide whether or not you wish to participate in this study, it is
important for you to understand why the research is being done and what it will
involve. Please take the time to read the following information carefully and
discuss it with others if you wish.
1. What is the purpose of this study?
This project focuses on evaluating the prevalence of children with
finger/thumb sucking habits and how it may affect their teeth alignment
leading to a malfunction in the dental bite, known as a ‘anterior open bite’.
The project aims at identifying the individuals affected and educating
patients on their oral behaviours and attitudes as well as guiding them to
seek proper dental treatment where necessary.
Anterior open bite (AOB) describes the position where the front teeth don’t
contact during closure of the jaw causing individuals to have deficiencies
in function, speech, mastication and aesthetics. This leads to a term known
as malocclusion (abnormal bite), which is a term used to describe
abnormal contact of upper and lower teeth when the jaw is in closure.
There are several types of malocclusions, with AOB being one of the most
complex to diagnose and treat.
There is limited access for communities in regional and rural
demographics to dental services. In addition, treatment options available
in correcting the open bite are very costly and time consuming with lack of
public awareness by families of children affected in these regions. Hence,
carrying out this project will allow these families awareness in regional
communities on recognising and addressing this abnormal bite in children.
It is crucial for these children to have correct bite as it will impact on the
quality of their life. Individuals with anterior open bite experience
deficiencies in speech, mastication, function and aesthetics, thereby
impacting on their quality of life and self-esteem.
2. Why have I been invited to participate in this study?
We are seeking children aged 7-12 years and their families to participate
in this study. If you agree to participate in this study, you will be required
to fill out a simple questionnaire that should not take longer than 10
minutes to complete. The questionnaire can be handed back in its original
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envelope to your child’s teacher for collection by the researcher.
Information gathered from both questionnaire will assist dental
professionals to better manage and educate patients on importance of
contacts between teeth and its overall effects on the body.
3. What does this study involve?
If you agree to participate, you will be asked to fill out a simple
questionnaire about your child’s oral behaviours and their demographics
(age, gender, and sequence within the family household) as well as other
questions on medical conditions that may have an influence on alignment
of teeth.
4. Are there risks and benefits to me in taking part in this study?
No risks are associated with this study. All information collected will be
confidential. No personal information will be collected or published.
5. How is this study being paid for?
The research will be funded through the University with possible external
funding when approved.
6. Will taking part in this study cost me anything, and will I be paid?
Taking part in this study will not cost anything but no payments will be
made either. There is however, an oral health pack in the draw to win for
those who participate and wish to be a part of the draw.
7. What if I don’t want to take part in this study?
Participation in this research is entirely your choice. Only those people
who give their informed consent will be included in the project. Whether or
not you decide to participate, is your decision and will not disadvantage
you.
If you do decide to participate, and consent to your child participating, you
and your child may withdraw from the project at any time without giving a
reason and have the option of withdrawing any data, which identifies you.
8. What if I participate and want to withdraw later?
You have the right to withdraw from participation at any time and all
data/information collected will be returned to you.
9. How will my confidentiality be protected?
All data will be kept in a safe filing cabinet that is locked or in a computer
filed that has a password and only the investigators will have access to it.
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All data will be collected in a coded format and no personal information will
be identifiable by the researchers.
10. What will happen to the information that I give you?
All data will be presented in a coded/numerical format and will be as part
of a postgraduate thesis that will be published. No personal information
will be collected, disclosed or published.
11. What should I do if I want to discuss this study further before I
decide?
If you would like further information please contact Liyana Tanny on
0432033432.
12. Who should I contact if I have concerns about the conduct of this
study?
NOTE: Charles Sturt University’s Human Research Ethics Committee (for
low risk projects list the Faculty that approved the research) has approved
this project. If you have any complaints or reservations about the ethical
conduct of this project, you may contact the committee through the
Executive Officer:
The Executive Officer
Human Research Ethics Committee
Tel: (02) 6338 4628
Email: [email protected]
Any issues you raise will be treated in confidence and investigated fully
and you will be informed of the outcome.
Thank you for considering this invitation.
This information sheet is for you to keep.
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Appendix II. Consent Form
CONSENT FORM (Parent/Guardian)
Chief researcher:
Liyana Tanny
Postgraduate student and Oral Health Therapist
Project Supervisors:
o Professor Boyen Huang – Head of School, School of Dentistry and Health
Sciences, Charles Sturt University, President-elect of IADR Australian and
New Zealand Division
Expertise: Paediatric dentistry, and health care
administration
o Dr Geoffrey Currie – Associate Professor, School of Dentistry and Health
Sciences, Charles Sturt University
Expertise: Medical Radiation, clinical trial and statistics
o Dr Ashraf Shaweesh – Lecturer in Oral Health, School of Dentistry and
Health Sciences, Charles Sturt University
Expertise: Head and neck anatomy
I agree for my child to participate in the above research project and give my
consent freely.
I understand that the project will be conducted as described in the Information
Statement, a copy of which I have retained.
I understand that my child can withdraw from the project at any time and do not
have to give any reason for withdrawing.
I consent to
Filling out the questionnaire which will be analysed by the researchers
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The researchers accessing all information I disclose on the questionnaire
I understand that my personal information will remain confidential to the
researchers
I have had the opportunity to have questions answered to my satisfaction
Print Name:
_________________________________________________________
Signature______________________ Date: _________________
NOTE: Charles Sturt University’s Human Research Ethics Committee (for low
risk projects list the Faculty that approved the research) has approved this
project. If you have any complaints or reservations about the ethical conduct of
this project, you may contact the committee through the Executive Officer:
The Executive Officer
Human Research Ethics Committee
Tel: (02) 6338 4628
Email: [email protected]
Any issues you raise will be treated in confidence and investigated fully and you
will be informed of the outcome.
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Prevalence and determinants of Non-Nutritive Sucking on Anterior Open
Bite in Children Attending Primary School
CHANCE TO WIN AN ORAL HEALTH PACK
If you wish to go into the draw to win an oral health pack, please provide your
email address and return along with your questionnaire.
Email: __________________________________________________________
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Appendix III. Questionnaire
QUESTIONNAIRE
Number coding of Child: Date of Child Birth: /………/……….
Sequence of child amongst siblings:
1. Highest schooling level of Parent filling the form
Primary
Secondary
TAFE (Diploma/apprentice/certificate)
Tertiary (undergraduate)
Tertiary (postgraduate)
2. Is your child enrolled in a private or public primary school?
Private
Public
3. Has your child ever presented with finger/thumb-sucking habits? Circle
correct answer(s)
No
Yes:
o Less than 6 months duration
o 6 months duration
o More than 6 months duration
o More than 12 months duration
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4. Age of onset of thumb-sucking
6 months old
12 months old
2-5 years old
5. What form of feeding did your child experience as a baby? Please circle
the correct answer(s).
Breast-feeding
Bottle feeding
Mixed breast and bottle feeding
6. What form of non-nutritive sucking did your child used as a baby?
Please circle correct answer(s).
Pacifiers/dummies
Finger/thumb-sucking
Other objects/toys
None
7. Does your child have or had any sleeping problems, such as snoring,
mouth-breathing? Please circle correct answer(s)
No
Snoring
Mouth breathing
Sleep-apnoea
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8. Has your child ever had or was told to require to have surgeries for
tonsils, grommets or adenoids? Please circle correct answer(s)
No
Tonsils
Adenoids
Grommets
9. Has your child undergone or is undergoing any orthodontic treatment
(such as braces)?
Yes
No
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Appendix IV. Dental Occlusion illustration component of the questionnaire.
Normal bite
Under-bite
Protrusion (Overjet)
Overbite
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Open-bite
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Appendix V. Letter to Schools
Letter of Information and Permission (Schools)
Prevalence and determinants of Non-Nutritive Sucking on Anterior Open
Bite in Children Attending Primary School
Chief researcher:
Liyana Tanny
Postgraduate student and Oral Health Therapist
Project Supervisors:
o Professor Boyen Huang – Head of School, School of Dentistry and Health
Sciences, Charles Sturt University, President-elect of IADR Australian and
New Zealand Division
Expertise: Paediatric dentistry, and health care
administration
o Dr Geoffrey Currie – Associate Professor, School of Dentistry and Health
Sciences, Charles Sturt University
Expertise: Medical Radiation, clinical trial and statistics
o Dr Ashraf Shaweesh – Lecturer in Oral Health, School of Dentistry and
Health Sciences, Charles Sturt University
Expertise: Head and neck anatomy
Invitation
You are invited to participate in a research study on assessing prevalence and
effects of non-nutritive sucking on anterior open bite in children attending your
school and aged 7 to 12 years.
The study is being conducted by Liyana Tanny, an Oral Health Therapist and
current Postgraduate student in the School of Dentistry & Health Sciences at
Charles Sturt University.
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Before you decide whether or not you wish to participate in this study, it is
important for you to understand why the research is being done and what it will
involve.
The study will involve providing a short questionnaire to parents/guardians of the
children attending the school between the ages 7 and 12, following providing
information on the study and gaining written consent. The questionnaire will
comprise questions regarding oral habits of children (such as thumb
sucking/pacifier use), social history (including breastfeeding/bottle-feeding) as
well as questions regarding medical conditions.
Anterior open bite (AOB) is a type of dental malocclusion (abnormal bite). It
describes the lack of contact between the upper and lower front teeth during
maximum closure of the jaw. AOB is one of the most difficult bites to treat
requiring much intervention and is hence very costly. Individuals with anterior
open bite have deficiencies in speech, chewing, swallowing and have a low self-
esteem affecting the quality of their life. In addition, AOB has a high relapse rate
even with orthodontic and surgical treatment.
This study will check the prevalence of children with anterior open bite.
Furthermore, it will evaluate the link between the abnormal bite and oral habits
(thumb-sucking/pacifier use). Through this, we can identify the abnormal bite
from an early age and provide early interventions or prevention to those affected.
I approve to let Ms Liyana Tanny approach and invite parents and students to
participate in this research project. I also approve to having children go through
a simple dental check-up during the school hours in the classroom with the
teacher present. I have had the opportunity to have questions answered to my
satisfaction
Principle name: ________________________________________
Signature_________________________ Date: _________________
NOTE: Charles Sturt University’s Human Research Ethics Committee (for low
risk projects list the Faculty that approved the research) has approved this
126
project. If you have any complaints or reservations about the ethical conduct of
this project, you may contact the committee through the Executive Officer:
The Executive Officer
Human Research Ethics Committee
Tel: (02) 6338 4628
Email: [email protected]
Any issues you raise will be treated in confidence and investigated fully and you
will be informed of the outcome.