Abstract
In order to investigate the correlation between the morphology of the orofacial skeleton and the function of the masticatory muscles by measuring jaw closing force, the cephalometric measurements and the jaw closing force of the masticatory muscles of 50 male and 67 female subjects, 9 to 14 years of age, were statistically examined for their relation and the following tendency toward correlation was found. 1. Both males and females with a larger morphology of the orofacial skeleton showed a remarkable tendency toward a stronger jaw closing force. 2. A highly significant positive correlation was found, in both males and females, between the jaw closing force and the age. In other words, jaw closing force increased with aging. 3. A highly significant positive correlation was found, in both males and females, between the jaw closing force and the posterior facial height. 4. In males, a significant negative correlation was found between the jaw closing force and each of the followings : mandibular plane angle, occlusal plane angle, gonial angle, and the ratio of the anterior facial height to posterior facial height. A significant positive correlation was also found between AB difference. Subjects with Angle class II. div. II type morpholgy of orofacial skeleton showed a tendency toward a stronger jaw closing force. 5. No significant correlation was found, either in males or females, between the depth of the antegonial notch and the jaw closing force.
