In Class II treatment, the challenge is normally to bring the lower incisors sufficiently forward to coordinate them with the PIP for the upper incisors, as determined in Stage 1 of the treatment planning. This is true both in Class 11/1 treatment, and in the second phase of Class 11/2 treatment, after initial upper arch alignment has converted the case into effectively a Class N/1 malocclusion.
In orthodontic treatment mechanics, the lower incisor A/P position relative to the upper incisors can be changed by three main factors:
1. Movement of lower incisors in the mandibular bone (Fig. 7.28)
2. A change in the length of the mandible (Fig. 7.29)
3. A change in the A/P position of the mandible, due to changes in the position of the condyles in the fossae Fig-
Was this article helpful?