MAXILLOFACIAL MORPHOLOGY AND MASSETER MUSCLE THICKNESS IN ADULTS

The aim of this study was to investigate how the thickness of the mass eter muscle relates to the maxillofacial morphology, including the thi ckness of alveolar process in the mandibular incisor region, and the t hickness of the mandibular symphysis. The subjects consisted of 80 adu lt male volunteers (mean age: 23 years 8 months). The relationship bet ween masseter muscle thickness and the maxillofacial skeleton was inve stigated by measuring the former by ultrasonography and the latter by roentgenographic cephalometry. The data were initially analysed using a multiple regression analysis. Thereafter, correlation coefficients w ere obtained by a simple regression analysis. The following results we re found: 1. The thickness of the masseter muscle (mean +/- SD) was 15 .8 +/- 3.0 mm in the relaxed state and 16.7 +/- 2.7 mm at maximal clen ching. 2. Masseter muscle thickness was negatively correlated with the mandibular plane angle. 3. Masseter muscle thickness was positively c orrelated with the mandibular ramus height (Cd-Go), and the thickness of the alveolar process and that of the mandibular symphysis. It is th erefore suggested that masticatory function influences the morphology of the mandible.