Journal of Dental Research, Vol 73, 1142-1149, Copyright © 1994 by International & American Associations for Dental Research Online Journals
Relationship between attachment of the superficial masseter muscle and craniofacial morphology in dentate and edentulous humans
K. Kasai, L. C. Richards, E. Kanazawa, T. Ozaki and T. Iwasawa
Department of Orthodontics, Nihon University School of Dentistry, Chiba, Japan.
Previous studies have described the importance of the interaction between
the masticatory muscles and the craniofacial skeleton in the control of
craniofacial growth. This study describes the attachment and orientation of
the superficial masseter muscle and its relationship with craniofacial
morphology in dentate and edentulous subjects. Data were obtained from
lateral cephalometric radiographs of a total of 31 cadavers in which the
superficial masseter muscle had been defined with liquid barium. The
results provide evidence that the morphology of the superficial masseter
muscle in the gonion region differed significantly between dentate and
edentulous subjects, with the masseter being 2.7 mm wider and the
gonion-anterior muscle border distance being 4.0 mm greater in dentate
subjects. The complex relationship between craniofacial morphology and the
dimensions and inclination of the superficial masseter muscle were most
clearly evident in dentate subjects where the position of the anterior
border was related to ramus dimensions and mandibular and occlusal plane
angles. The association is much less clear in edentulous subjects where
normal function was disturbed. In general, age was not a significant
determinant of variation in superficial masseter muscle dimensions and
orientation.
