Facial features of class II division 2 malocclusion include a square/round pleasing face, prominent chin, deep labio-mental sulcus, hyperactive lower lip, a high lower lip line, thin upper lip, small gonial angle and horizontal type of face. The masseter and temporalis muscles are broad, and these subjects have a strong biting force. The lips are usually thin, and there is a lack of vertical development of the face below the nose ( Fig. 68.1 ).

Profile of a patient with class II division 2 malocclusion.

A square or a round face, backwardly held mandible with a thick chin button and thin lips.

Dental features include a class II molar and canine relationship, deep traumatic bite, retroclined upper four incisors or retroclined central incisors with a labial inclination of the laterals and supra-erupted upright lower incisors. The tooth size may be small, and the upper incisors may have an increased collum angle between the crown and the root ( Fig. 68.2 ). The incisors are relatively thin with small tubercles. Class II division 2 incisors have a shorter root, a longer crown, axial bending of the incisor and reduced labio-palatal thickness.

Occlusion of class II division 2 malocclusion.

(A) There is a deep traumatic bite, retroclined maxillary central incisors, proclined laterals and crowding in the mandibular arch. (B) The collum angle can be measured as an angle between the long axis of the crown and the long axis of the root. It may exhibit an increased collum angle when measured as an external angle.

The maxillary incisors in class II division 2 malocclusion are about 12 degrees more vertical than those in normal occlusion. The mandibular incisors are upright in a class II division 2 malocclusion but to a lesser extent than the upper incisors. Not only are the upper and lower incisors more recumbent, but they are also more retrusive. The maxillary arch is often wide in the posterior region and crowded in the anterior region. However, there is a transverse underdevelopment of the mandible from canine to canine, which is probably a factor responsible for mandibular incisor compression and crowding. Consequently, these malocclusions are associated with severe deep bites ( Fig. 68.2 ).

• 1.

  Based on freeway space

  • There are two subtypes of class II division 2 malocclusions:

    • a.

      Such as the type in which the patient has excessive freeway space with a lack of posterior alveolar development and anterior alveolar overgrowth and

    • b.

      That in which the patient has normal freeway space.

• 2.

  Based on dental features:

  • van der Linden described three types of class II division 2 patterns based on the alignment of incisors and canines.

    • Type A: All four maxillary incisors are palatally tipped, and the maxillary canines are well aligned ( Fig. 68.3 ).

      

      Class II division 2 type A.

      The four permanent maxillary incisors are tipped palatally, while the maxillary canines are well aligned in the dental arch.

    • Type B: The maxillary central incisors are palatally tipped, and the lateral incisors are labially tipped ( Fig. 68.4 ).

      

      Class II division 2 type B.

      The maxillary central incisors are palatally tipped, and the lateral incisors are labially tipped.

    • Type C: All four maxillary incisors are palatally tipped, and the canines are buccally placed ( Fig. 68.5 ).

      

      Class II division 2 type C.

      The four maxillary incisors are tipped palatally, and the canines are placed buccally.

The anterior cranial base lengths and sagittal position of the maxilla are normal relative to class I and class II division 1 malocclusions. In contrast, class II division 2 malocclusions have a shorter or normal mandibular length with its sagittal position retruded, the chin is prominent and the lower posterior facial height is increased.

The mandibular growth vector is horizontally oriented, with a flat mandibular plane, giving the appearance of a hypo-divergent facial pattern. The gonial angle is acute. The lower incisors have a normal inclination relative to the mandibular plane but are retroclined relative to the facial plane. The inter-incisal angle is large, and the overbite is deep due to infra occlusion of the molars. There is an extreme skeletal mandibular counterclockwise rotation rather than dentoalveolar supra eruption.