title: [Histopathological effects of overextended opening of the mouth on the temporomandibular joint and masticatory muscles].
abstract: The purpose of this study is to explore the effects and the pathogenicity of overextended mouth opening on the temporomandibular joint (TMJ) and the masticatory muscles. In this experiment, the animal model of overextended opening was, established by overly opening the miniature pigs' mouths for certain periods with mouth gag, and then the TMJ and the masticatory muscles were studied histopathologically. The results showed that the histosytes of the TMJ and the masticatory muscles had suffered injury, proliferation, atrophy and degeneration from the overextended opening, and the extents of deterioration became greater with the increase of frequency and duration of overextended opening. Among the injured tissues, the cartilage of the condyle, the posterior and anterior portions of the articular disc, the anterior extenting tissue of the disc, the lateral perygoid muscles and the temporalises underwent the most obvious histopathological changes. The result of this study confirms that overextended mouth opening is one of the pathogenic factors of CMD, and it has great significance for the clinical diagnosis, treatment and prevention for CMD.
authors.affiliation: Department of Stomatology, General Hospital of PLA, Beijing.
authors.forename: H
authors.initials: H
authors.lastname: Wang
authors.forename: J
authors.initials: J
authors.lastname: Zhou
authors.forename: M
authors.initials: M
authors.lastname: Hong
mesh_terms: D000818:Animals; D017271:Craniomandibular Disorders / Q000209:etiology / Q000473:pathology*; D005260:Female; D008297:Male; D008410:Masticatory Muscles / Q000473:pathology* / Q000648:ultrastructure; D013552:Swine; D013556:Swine, Miniature; D013704:Temporomandibular Joint / Q000473:pathology* / Q000648:ultrastructure