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.