Pathognomonic DIV 2 JC 5
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Transcript of Pathognomonic DIV 2 JC 5
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Naphtali Brezniak, Arnon Arad, Moshe Heller
Ariel Dinbar, Arieh Dinte,; Atalia Wasserstein
Angle Orthodontics
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An ovoid arch form design will provide the most estheticand stable form for most patients
This ovoid arch form will be very esthetic because theposterior teeth (buccal segments) are sequentially
expanded, filling the patient's buccal corridors
8. Arch form
Leveling the curve of Spee inthe mandibular arch iscritical to the correction ofdeep bites and themaintenance of overbite
correction.
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It should be emphasized that a certain degree ofbackward mandibular rotation frequently occurs duringthe process oforthodontic leveling of the curve of Speecaused by the extrusion of the posterior teeth.
Therefore, in patients with steep mandibular planes andopen bite tendencies, backward mandibular rotationcould be minimized by placing a high pull face bow
during treatment.
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Features:
1.Mandibular molars assume a
posterior position with respect to maxillary
1st molars and maxillary arch.2.Mandibular arch may or may not show
any individual irregularities but usually has
exaggerated curve of spee.3.Supraversion of mandibular incisors.
4.Mandibular labial gingival tissue is often
traumatized
FEATURESOFCLASS
II DIVISION-2
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5.Maxillary arch is wider than normal in
inter canine region.
6.Remarkable and constant distinguishing
feature is lingual inclination of maxillary
centrals and labial inclination of lateral incisors.
7.Excess overbite (closed bite)
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8.
8.Abnormal path of closure due to combination of lingual
inclination of maxillary incisors and infraocclusion of posteriors
result in mandible to be forced into retruded tooth guidance
with condylar movement posteriorly and superiorly in articular
fossa creating a displacement.
9.Electromyographic research shows with dominance of the
posterior fibers of both temporalis and masseter muscles
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Features Class II division 1 Class II division 2
Profile Convex Straight to mild
convexity
Lips
upper
lower competency
Short
evertedincompetent
Normal
NormalCompetent
Mentalis muscle Hyperactive -
Lower facial
height
Normal or increased Decreased
Arch form V shaped Square, U shaped
Mentolabial
sulcus
Deep Deep or normal
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Palate Deep Normal
Incisors Proclined Centrals are
retroclined
Overjet Increased Decreased
Overbite Deep overbite Closed bite
Crown root Normal angulation Axis of crown and
root are bent and is
referred to as collum
angle
Path of closure Normal Backw
Interocclusal
clearance
Normal/increased/
decreased
increased
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In general, Class II Division 2 malocclusions are easier to correct during thegrowth period than in adulthood, especially when favorable growth occursduring treatment.
A number of factors need to be considered when planning treatment forthese patients.
Treatment Considerations
in Class II Division 2 Malocclusions
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The abnormal axial inclination of the maxillary central incisors present theclinician with two difficulties:
maxillary
incisors.
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excessive lingual inclination of the maxillary incisors might have resulted in afunctional mandibular retrusion.
This could be determined by "freeing the mandible either by tipping themaxillary central incisors labially or by placing a bite plate to disarticulate
the anterior teeth allowing the mandible to assume a position dictated bythe musculature.
Excessive lingual inclination
of the maxillary incisors
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Furthermore, the labial movement of the maxillary incisors will facilitate theuncrowding ofthe mandibular incisors by allowing the tongue and lipmusculature to establish the position of the lower incisors without theconfining influence of the lingually tipped maxillary incisors.
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To be able to completely retract the maxillary incisors and correct theoverjet, their incisal edges have to clear the brackets placed on the lower
incisors.
Therefore, leveling the dental arches during orthodontic treatment is abiomechanical necessity.
Correction of the deep bite and the
exaggerated curve of spee
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Strang believes that with good vertical growthduring treatment, the overbite can be successfullycorrected by intruding the anterior teeth.
He suggested that in these very deep overbite cases,the extrusion of the posterior teeth in the absence ofvertical growth will result in a muscular imbalancethat will cause a relapse of the corrected overbite.
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Utility arch Burstones inrusion arch
Connecticut intrusion arch
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Schudy, on the other hand, advocates extrusion of the posterior teethparticularly in patients with a decreased lower face height, a flat mandibularplane angle, and a prominent chin.
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It should be emphasized that a certain degree ofbackward mandibular rotation frequently occurs duringthe process oforthodontic leveling of the curve of Speecaused by the extrusion of the posterior teeth.
Therefore, in patients with steep mandibular planes andopen bite tendencies, backward mandibular rotationcould be minimized by placing a high pull face bow
during treatment.
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The Class II division 2 (Class II/2) malocclusion as
originally defined by E.H. Angle is relatively rare.The orthodontic literature does not agree on theskeletal characteristics of this malocclusion.
Several researchers claim that it is characterized
by an orthognathic facial pattern and that the
malocclusion is dentoalveolar per se. Othersclaim that the Class II/2 malocclusion has unique
skeletal and dentoalveolar characteristics.
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The present study describes the skeletal and
dentoalveolar cephalometric characteristics of50 patients clinically diagnosed as having Class II/2
malocclusion according to Angles original criteria.
The study compares the findings with those of botha control group of54 subjects with Class II division
1 (Class II/1) malocclusion and a second controlgroup of 34 subjects with Class I (Class I)malocclusion.
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The findings demonstrate definite skeletal
dentoalveolar patterns with the followcharacteristics:
(1) the maxilla is orthognathic,
(2) the mandible has relatively short and retrognatparameters,
(3) the chin is relatively prominent,
(4) the facial pattern is hypodivergent,
(5) the upper central incisors are retroclined,
and (6) the overbite is deep.
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The results demonstrate that, in a sagittaldirection, the entity of Angle Class II/2malocclusion might actually be located between
the Angle Class I and the Angle Class II/1
malocclusions, with unique vertical skeletalcharacteristics.
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MATERIALSANDMETHODS
The experimental data consisted of the records
of50 patients who fit Angles original criteria fora Class II/2 malocclusion selected from 4400
records of orthodontic patients treated during
the past 8 years in the Israel Defense ForcesOrthodontic Department.
The cases were selected according to the clinical
charts, study models, and photographs.
Cases with a Class II/2 subdivision were omitted
from the stud .
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Both the Class I control group and the Class II/1 contrgroup were selected according to Angle criteria using
same procedure used for the experimental group
The experimental Class II/2 group included 21 boys an
29 girls with a mean 6 SD age of12.7 6 1.6 years and
an age range of 9.5 to 17.3 years
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The Class I malocclusion group included 15 boys and19 girls with a mean age of13.6- 6 1.8 years and an
age range of 9.7 to 16.7 years.
The Class II/1 malocclusion group included 30 boys
and 24 girls with a mean age of12.5 6 1.4 years and
an age range of 9.7 to 15.2 years.
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The characteristics and relative position of
Class II/2 malocclusion in comparison withother malocclusions is still controversial. This
controversy might be the result of the
composition of each study group (mean age,age range,ethnicity, sample selection criteria,
sample size, etc), the cephalometric points
identified, and the types of statistical testsused.
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Sagittal skeletal parameters
Sagittal skeletal parameters are shown in Tables 1through 3.
The results of this study demonstrate that themaxillary sagittal position of the three
malocclusion groups
is similar.
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The mandible in patients with Class II/2
malocclusion is described in the literature asbeing small and retrognathic when compared
with the mandible in patients with Class I
malocclusions.
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The Class II/2 malocclusion parameters
consistently had values that were between
those of the Class I and Class II/1 malocclusions.
This indicates that there is a general tendency for
a shorter and more retrognathic mandible inClass II/2 malocclusion in comparison with Class I
malocclusion and a longer and more prognathic
mandible in comparison with Class II/1
malocclusion.
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Other studies have reached similar conclusions
regarding the intermediate value of themandibular sagittal position in Class II/2malocclusion, whereas Blair described a mild
prognathic mandible.
Renfroe found a comparatively longer mandible in
Class II/2 malocclusion, and Kerr et al and Adamsfound no difference in the morphology of the
mandible of Class II/1 and Class II/2 malocclusions.
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In the present study, the chin (Pog to NB) wasfound to be prominent. This is in agreement with
Karlsens description of the cephalometric
pattern of Class II/2 malocclusion.
On the other hand, Smeets, Houston, Kerr et al,
and Pancherz et al did not find a prominent chinin their Class II/2 study group.
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With respect to the intermaxillary relationship,
Hitchcock reported a statistically significant
difference of the ANB angle between Class I, ClassII/1, and Class II/2 malocclusions.
Karlsen found a statistically significant differencein the ANB angle between Class I and Class II/2
malocclusions.
Fischer-Brandies et al concluded that the A-B planeis the most reliable discriminating parameter
between Class I and Class II/2 malocclusions.
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In the present study, the WITS appraisal and the
distance between points A and B on the palatal
plane (App-Bpp), both projected parameters, werethe only two parameters that differentiated
between all three groups with statistical
significance.
However, when pogonion was used as the
mandibular anterior landmark (App to pogonion onthe palatal plane[Pogpp] and angle of convexity),
there was no statistically significant differencebetween the Class II/2 and Class I groups.
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This could explain why some researchers have
described Class II/2 malocclusion as having anormal skeletal pattern, focusing the problem on
the dentoalveolar complex.
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The differences in the vertical dimension
between the Class II/2 group and the two
control groups were conclusive.
The numbers (Table 4) and the graphical
depiction (Figure 3) clarify this statement.
The vertical characteristics of Class II/2malocclusion include a flat mandibular plane,
an acute gonial angle, an enlarged posterior
facial height, a reduced anterior facial height,and a more horizontal growth vector asindicated by the DownsY-axis and Ricketts
facial axis.
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The preceding list describes a definite
hypodivergent facial pattern in the Class II/2malocclusion group.
A review of the literature reveals a wide
agreement regarding the enlarged posteriorfacial height in Class II/2 malocclusion.
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As for the inclination of the mandibular plane,several studies, are in agreement with the present
one, indicating a low mandibular plane angle in
Class II/2,
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The present study, as well as those ofBlair and
Wallis, found a more acute angle in Class II/2malocclusion in comparison with Class I and ClassII/1 malocclusions.
Renfroe described a more acute gonial angle inboth Class II groups as compared with a Class I
group.
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Anterior cranial base
Houston28 described a longer anterior cranialbase in both divisions of Class II malocclusion ascompared with Class I malocclusion.
This finding led him to theorize that in Class II
malocclusions, the retrognathic position of themandible is caused by a more posterior
articulation of the condyle. Wallis also found a
longer anterior cranial base and a more obtusecranial base angle in Class II/2 malocclusion.
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Dentoalveolar parameters
Angles original definition of Class II/2
malocclusion is based solely on dentoalveolarcriteria.
Therefore, it is not surprising to find broad
agreement in the literature regarding the mostevident dentoalveolar cephalometric
characteristics of this malocclusion, such as a
pronounced retroclination of the upper centralincisors,* an obtuse interincisal angle, and a deep
overbite. These findings
are in full agreement with the results of the
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With regard to the lower incisors, numerous
studies have described these incisors as having a
retroclined position, whereas other studies havefound them to have a normal inclination.
In this study both, retroclination to the facial
plane and in normal position to the mandibularplane was found.
These results may explain the apparentlycontradictory results published in the literature.
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The results of the present study
demonstrate a normal vertical position of
the upper central incisors relative to thepalatal plane. This is in agreement with thefindings of other researchers.
All of these studies have also described anormal vertical position of the lower
incisors relative to the mandibular plane. It
was found that the lower incisor tomandibular plane (L1 to MP) distance wasrelatively short.
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This finding was rather surprising, since one ofthe dentoalveolar characteristics of Class II/2malocclusion is a deep overbite.
Deep bite is usually the result of overuption. Thismight lead to a greater distance between theedges of the incisors to the palatal plane ormandibular plane, respectively.
Here, although there was a deep overbite, didnot find increased distances as expected.
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The results of this study might suggest that
the deep bite characteristic of Class II/2malocclusion is more skeletal thandentoalveolar, with significant mandibular
anterior rotation without vertical build-up
compensation of the lower border of thesymphysis.
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Most common is perhaps a deep
mento-labial sulcus over a prominent chin.
Craniofacial characteristics in two groupsof children were compared. In one group
(n::=22) the children had Angle Class
IIdivision 2 malocclusion combined withextreme deep bite. The other group (n::=25)
was composed of children with ideal
occlusion. The mean ages of the children
dive 2 malocclusion combined
with extreme deep bite Alf Tor Karlsen,
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In the Class 11-2 group the distance between
gonion and B-point was underdeveloped,
causing B-point to have a retruded
position in relation to both A-point and cranialbase. The Class 11-2 children also had a
retroclination of the symphysis, which
gave the B-point a retruded position inrelation to pogonion.
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As for vertical dimensions, Class 11-2 children
had a smaller anterior lower facial height thannormal. Furthermore, Class
11-2 had a discrepancy between the maxillary
incisal and molar heights, i.e. a slightly largerincisal height and a slightly smaller
molar height. Finally, children with Class 11-2had a high lip line and a very large interincisalangle.
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Three variables - the sagittal distance
between points A and B, the inclination ofthe symphysis, and the relationship
between the maxillary incisal and molar
heights - in combination, differentiatednearly 100% correctly between Class 11-2
and normal occlusion.
f th Sk l t l M h l fCl I
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Tht' angle S-N-A was
2.25 degrees greater in Class II, Div.
2 than in Class I indicating a more forward
positioning of the maxilla. Thus,
the Class II, Div. 2 mean pattern, when
compared to that of Class I, exhibits a
forward position of both maxilla and
mandible and a more horizontal lower
mandibular border.
oftheSkeletal Morphology ofClass I,
Class II,Div. 1, and Class II,Div. 2
(Angle)Malocclusions. *
EUGENE S. BLAIR,
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CONCLUSIONS
Relative to Class I and Class II/1 malocclusions,
ClassII/2 malocclusion has the followingcephalometric characteristics:
1. The maxillary length and sagittal positions are
similar.
2. The mandibular length is shorter, and itssagittal position is retruded.
3. The chin is prominent.
4. The anterior-posterior jaw relationships are
similar.
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5. The posterior facial height is definitely
enlarged.6. The mandibular growth vector is horizontallyoriented, and the mandibular plane is flat,
creating the appearance of a hypodivergent facialpattern.
7. The gonial angle is acute.
8. The anterior cranial base lengths are normal.
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9. Values for all Class II/2 malocclusion sagittal
parameters with the exception of one parameter
(Pog to NB) lie between those of Class I and ClassII/1 malocclusions.
10. The upper central incisors are in pronouncedretroclination.
11. The lower incisors have a normal inclination
relative to the mandibular plane but areretroclined relative to various facial planes.
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12. The interincisal angle is obtuse.
13. The overbite is deep, probably due toextreme skeletal mandibular counter clockwise
rotation rather than dentoalveolarovereruption.
14. The overjet is normal.
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Finally, we conclude that Angle Class II/2
malocclusion has not only a pathognomonicdental appearance, but also several skeletal,
sagittal, and especially vertical attributesthat
differentiate it from both Class I and Class II/1malocclusions.