The etiology and pathogenesis of angle's “Class two” malocclusion

Abstract

1.1. The angles SNA and SNB, and especially the difference between them, are a good basis on which to evaluate and plan treatment.2.2. Normal face samples show variation in apical base orientation with compensating variations in the positions of the teeth.3.3. Treatment objectives should aim at reducing high ANB angles to as near 0 to 2 degrees as possible.4.4. Good facial harmony is found in both prognathic and orthognathic persons so long as the apical base orientation does not exceed a range permitting compensating dental adjustments.5.5. Patients treated during periods of active growth respond with better apical base changes than do patients treated during nongrowth periods.6.6. The nature of the change in relationships of points A and B is influenced materially by the type of treatment followed.7.7. The ideal position of the lower incisor (3 mm. anterior to the NB plane) should not be maintained where the apical base dysplasia cannot be reduced to 4 degrees during treatment. Therefore, a flexible scale for incisor orientation is presented in Table 1.8.8. The greatest angular changes occur in the SNA angle.9.9. The treatment response most desired in most Class II cases is one of forward mandibular positioning due to alteration in the amount and direction of growth, primarily in the growth site at the head of the condyles.10.10. The use of Class II elastics of sufficient pull for a long enough period of time to bring about the desired mandibular growth response necessitates the tipping back of mandibular teeth to positions of dynamic anchorage in the first stages of treatment, as described by Tweed.11.11. The forward development of the lower third of the face is in harmony with the most common growth changes occurring at this time.12.12. Good reductions in the ANB angle have taken place in nearly all cases having higher than a 4-degree ANB angle in which active growth occurred.