Previous studies have been indicating that the various mandibular forms were all related to each other with functional framework, and analyses have been showing that the mandibular changes closely corresponded to, and resulted from, the overall pattern of craniofacial structures. This study was aimed to identify the morphologic characteristics of the adult mandible amongst each classes of malocclusion.
Lateral cephalograms of 74 class I (0-3 degrees of ANB), 108 class II (over 3 degrees of ANB) and 90 class III (below ()degree of ANB) malocclusion were employed to digitize and statistically analyze through the angular measurements and tie computation of size ratios.
The following results and conclusion were drawn;
1. There computed no typical difference on mandibular form between the scope of the vertical and horizontal composition of classifications.
2. The greatest curvature formed by the corpus and the ramus was found in class III group.
3. The size ratio of the corpus to ramus was the highest in class III, then followed by the class II and class I in order.
4. The class III manifested the most outstanding ratios of longtitude to breadth in the ramus, and latitude to height in the corpus.
5. The class HE got the most prominent symphysis, in contrast that the class II showed the least.
6. The class I revealed the minimum difference of height in anterior and posterior part of the corpus.
7. The flexion in the crust of the mandible set the deepest at supramental area in the class If, on the top of that no significant differences on the posterior border of the ramus and lower border of the corpus among 3. groups.
It forced to conclude the class III got the longer corpus and ramus length than any other group and the higher ratio of corpus to ramus in length as well.
The class III attributed somewhat to the absolute size of the mandible.
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