OBJECTIVETo investigate the effect of unilateral mastication on glenoid fossae by means of animal experiment.

METHODSAn animal model of unilateral mastication was established by extracting right mandibular molars of Wistar rats. The rats were sacrificed in different period to examine the location changes of glenoid fossae through sagittal and horizontal plane.

RESULTSThe anterior points of glenoid fossae in non-masticatory side of experimental groups were more anterior than those in masticatory sides. The anterior points of the glenoid fossae of non-masticatory sides in experimental groups were more anterior than those of the same sides in the control groups after inducing unilateral mastication for two and four months. After inducing unilateral mastication for two and four months, the anterior and the posterior points of the glenoid fossae of non-masticatory sides in experimental groups became closer to the midline by comparison with masticatory sides as well as the same sides in control groups. Locations of glenoid fossae in masticatory sides showed no changes in comparison with the same side of the control groups.

CONCLUSIONThe forward and inward remodeling of the glenoid fossae can be observed after unilateral mastication was induce to the non-masticatory sides of experimental rats. It is concluded that unilateral mastication might be one of the etiologic factor of temporomandibular joint disorders.