title: Degenerative changes in rat condylar cartilage induced by non-matching occlusion created by scattered orthodontic teeth-moving.
abstract: The effect of occlusion on the temporomandibular joint (TMJ) is debated. By inserting rubber-bands that were replaced by self-curing resin one week later, the left maxillary and the right mandibular first-molars were moved and kept mesially in Sprague-Dawley (SD) rats in both experimental I (EXP-I) and II (EXP-II) groups, aiming to establish a non-matching cusp-to-fossa occlusal relation. Four weeks later, the left maxillary and the right mandibular third-molars were moved and kept distally in the EXP-II group. Degenerative changes, typically as a cell-free area, were observed in TMJs of the EXP groups. Binary logistical analysis indicated that the odds ratio of EXP group, EXP-II vs. EXP-I, on the incidence of a cell-free area, was 2.8 (p=.036). Time point, gender, and side did not have such effects (p>0.05). The results indicate that the persistence of more scattered non-matching cusp-to-fossa occlusion is more harmful to the condylar cartilage in terms of the incidence of degenerative changes.
authors.affiliation: Department of Temporomandibular Joint Disorders and Occlusion, School of Stomatology, The Fourth Military Medical University, China. mqwang@fmmu.edu.cn
authors.forename: Meiqing
authors.initials: M
authors.lastname: Wang
authors.forename: Lei
authors.initials: L
authors.lastname: Sun
authors.forename: Shi-Bin
authors.initials: SB
authors.lastname: Yu
authors.forename: Xiaodong
authors.initials: X
authors.lastname: Liu
authors.forename: Kai
authors.initials: K
authors.lastname: Jiao
authors.forename: Guo-Wei
authors.initials: GW
authors.lastname: Wang
authors.forename: Lei
authors.initials: L
authors.lastname: Liu
authors.forename: Jian-Jun
authors.initials: JJ
authors.lastname: He
mesh_terms: D000818:Animals; D002358:Cartilage, Articular / Q000473:pathology*; D016923:Cell Death; D019902:Chondrocytes / Q000473:pathology; D003970:Diastema / Q000473:pathology; D005260:Female; D006984:Hypertrophy; D008297:Male; D008310:Malocclusion / Q000150:complications*; D008335:Mandibular Condyle / Q000473:pathology*; D008963:Molar / Q000473:pathology; D008964:Molar, Third / Q000473:pathology; D010003:Osteoarthritis / Q000209:etiology* / Q000473:pathology; D051381:Rats; D017207:Rats, Sprague-Dawley; D013705:Temporomandibular Joint Disorders / Q000209:etiology* / Q000473:pathology; D014087:Tooth Movement Techniques / Q000009:adverse effects