Angle’s class II Malocclusion In sagittal plane this malocclusion is called as postnormal occlusion. According to lischer’s modification of angle’s classification this malocclusion is known as distocclusion. The term class II is an unfortunate generalization which groups together morphologies of wide ranging varieties often with one common trait – their abnormal molar relationship. www.indiandentalacademy.com
According to Angle’s classification a class II malocclusion indicates that the mandibular arch is in a distal relation to that of the maxilla. Class II malocclusion is characterized by a class II molar relationship where the disto-buccal cusp of the upper first permenent molar occludes in the mesio-buccal groove of the lower first permenent molar. www.indiandentalacademy.com
Angle divided the class II malocclusion into two divisions based on the labiolingual angulation of the maxillary incisors as-
Class II,division 1: the molar relationship is class II with the upper anteriors proclined.
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Class II,division 2: the molar relationship is class II and the upper central incisors are retroclined and overlapped by the lateral incisors. Class II,subdivision: is said to exist when the molar relationship is class II on one side and class I relation on the other side. Ex-class II,division 1,subdivision.
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Class II division 1 malocclusion Incidence- 25-30%. Skeletal features: 1) Maxillary protrusion. 2) Mandibular retrusion. 3) Combination of above.
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Etiological considerations: Pre-natal factors: 1) Hereditary. 2) Teratogenesis. 3) Irradiation. 4) Intra-uterine fetal posture.
Natal factors: Improper forceps application during delivery. www.indiandentalacademy.com
Post-natal factors: 1) 2) 3) 4)
Sleeping habits. Traumatic injuries. Long term irradiation therapy. Infectious conditions like rheumatoid arthritis. 5) Pernicious habits like thumb sucking. 6) Anomalies of dentition like congenitally missing teeth etc.. www.indiandentalacademy.com
Features of class II division 1 Extraoral features: •Convex profile. •Posteriorly divergent face. •Deep mento labial sulcus. •Oval shaped face(mesocephallic to dolicocephalic in frontal view.)
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Extraoral features: (contd.) •Incompetent lips. •Short hypotonic upper lip. •Everted lower lip. •Hyperactive mentalis activity. •Abnormal perioral musculature. •Deficient lower facial height. •‘lip trap’ (sometimes). www.indiandentalacademy.com
Intraoral features: •Class II molar relationship. •Class II incisior and canine Relation(not necessarily) •Increased overjet. •Narrow ‘V’ shaped upper arch. www.indiandentalacademy.com
Intraoral features: (contd.) •Deep palate. •Supraversion/overeruption of Lower anteriors. (‘flattening’ tendency). •Deep bite (may be traumatic). • Exaggerated curve of spee. •Others (openbites/posterior cross bites) www.indiandentalacademy.com
Diagnosis Factors to be considered: 1) Skeletal or dentoalveolar origin. 2) True or functional class II. 3) Probable growth direction. 4) Treatment timing. 5) Etiological considerations.
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Functional criteria: 1) Relationship between rest position and occlusion. 2) Relationship between overjet and function of lips. 3) Posture and function of tongue. 4) Mode of breathing.
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Cephalometric criteria: 1) Relationship of maxilla to the cranial base. 2) Position and size of mandible. 3) Axial inclination and position of the incisiors. 4) Growth pattern.
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Classification of class II Malocclusions Morphological Classification: 1) Class II dentoalveolar malocclusions. 2) Class II with retrognathic mandible. 3) Class II with prognathic maxilla. 4) Class II combination type.
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Cephalometric Classification: 1) Class II sagittalrelationships without skeletal components. • Normal ANB angle. • Usually SNA and SNB angles are reduced. • Labial tipping of the upper incisors is likely. • Uprighting of incisors is done. www.indiandentalacademy.com
2) Functionally created class II malocclusion, with forced mandibular retrusion in habitual occlusion but with normal postural rest position. •ANB angle is smaller in habitual occlusion. •Early interceptive functional therapy is method of choice. www.indiandentalacademy.com
3) Class II malocclusion with the fault in the maxilla •Larger SNA angle or •Larger SNPr angle (dentoalveolar) •Simple tipping corrected with removable appliance. •Torque and bodily movement done with fixed appliance.www.indiandentalacademy.com
An upward and forward inclination aggravates the maxillary protrusion. This is called Pesudoprotrusion. •Upward or downward inclination results in an open bite or deep overbite. •Combined therapy (headgear and activator) www.indiandentalacademy.com
4) Class II malocclusion with faults in the mandible. •Smaller SNB angle. •Saddle angle is larger (normal size). •Conventional activator therapy.
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5) Combination type class II malocclusion •Prognathic maxilla and retruded mandible. •Retrognathic upper and lower jaws is also possible, treatment follows a combined functional and fixed appliance approach.
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Management Treatment principles depends on: 1) Age. 2) Nature and severity of problem. 3) Etiologic factors.
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There are three approaches: 1) Prevent malocclusion from occuring. 2) Intercept a developing malocclusion. 3) Correct an already existing malocclusion.
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Management of functional disturbances: •Mouth breathing – habit breaking appliance. •Abnormal tongue position and swallowing patterns- fixed or removable habit breaking appliance. •Lip posture and activity- lip exercises. •Finger sucking habit - fixed or removable habit breaking appliance. www.indiandentalacademy.com
Mixed dentition period (modifying growth):
Prognathic maxilla – headgears. Retrognathic mandible – activator, frankle and other bite jumping devices.
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Class II malocclusion in adults:
•Dentoalveolar compensation for the skeletal defect through reduction of tooth material is the treatment of choice – “Camouflaging”. •Generally maxillary first premolars are extracted.
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Severe class II skeletal discrepancy in adults: •Orthognathic surgery is considered. •Done only after cessation of growth. •Presurgical orthodontics should be considered in all cases. •Maxillary prognathism – Partial maxillary retropositioning (most commonly done). •Mandibular retrognathism – intraoral sagittal split osteotomy. www.indiandentalacademy.com
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