DIMENSIONAL DIFFERENCES IN THE CRANIOFACIAL MORPHOLOGIES OF GROUPS WITH DEEP AND SHALLOW MANDIBULAR ANTEGONIAL NOTCHING

Certain craniofacial characteristics were identified on the lateral ce phalograms of 40 untreated subjects with shallow mandibular antegonial notches and 40 subjects with deep notches. Subjects with shallow notc hes demonstrated more of the morphological characteristics usually ass ociated with horizontal mandibular growth patterns than did subjects w ith deep notches, and their mandibles were positioned more protrusivel y. In general, the mandibles of the shallow notch subjects proved to b e longer than mandibles of the deep notch subjects. On average, mandib les with deep notches showed greater genial angles, deeper posterior r amus notch depths, and larger occlusal plane inclinations. The total a nterior facial height of shallow notch subjects was much smaller than that of the deep notch subjects. The maxillae in deep notch subjects w ere more retrusive in relation to the cranial base when compared with the shallow notch subjects. A discriminant analysis was used to determ ine which combinations of variables were most consistently related to either deep or shallow mandibular antegonial notches. Eighty percent ( 80%) of the cases were classified correctly as deep or shallow notch c ases by means of this discriminant function.