title: Disc positions and condylar changes induced by different stretching forces in the model for anterior disc displacement of temporomandibular joint.
abstract: OBJECTIVE
  The aim of this study was to compare the disc positions and condylar changes induced by different stretching forces in the modified animal model for anterior disc displacement (ADD) of the temporomandibular joint.
  
  
  METHODS
  In the experimental group, 30 rabbits were equally divided into 3 subgroups and underwent surgical ADD via different stretching forces: group A with 0.5 N, group B with 1 N, and group C with 2 N. In the sham group, 6 rabbits underwent the same surgery without the disc being pulled anteriorly. The diagnosis of ADD was made when the anterior band of the disc was located anteriorly to the articular eminence. Histologic and radiographic changes of the condyles were observed under light microscopy and micro-computed tomography scanning 1 week after surgery.
  
  
  RESULTS
  The success rates of ADD were both 100% in groups B and C and 70% in group A. The correlations between the stretching force and severity of ADD, the stretching force and severity of cartilage changes, and the severity of ADD and cartilage changes were statistically significant (P < 0.01). The most advanced ADD and severest condylar changes were induced in group C. Condylar remodeling and scleroses were found in micro-computed tomography scans.
  
  
  CONCLUSIONS
  The rabbit model for ADD has been successfully established in this study, which is feasible and minimally invasive. The stretching force of at least 1 N could induce the disc displaced successfully. Larger stretching force would induce severer ADD and condylar degenerative changes.
authors.affiliation: From the Department of Oral and Maxillofacial Surgery, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, and Shanghai Key Laboratory of Stomatology, Shanghai, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Li
authors.forename: Xieyi
authors.initials: X
authors.lastname: Cai
authors.forename: Shaoyi
authors.initials: S
authors.lastname: Wang
authors.forename: Chi
authors.initials: C
authors.lastname: Yang
authors.forename: Hao
authors.initials: H
authors.lastname: Song
authors.forename: Linjian
authors.initials: L
authors.lastname: Huang
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena; D016723:Bone Remodeling / Q000502:physiology; D002358:Cartilage, Articular / Q000000981:diagnostic imaging / Q000473:pathology; D004195:Disease Models, Animal; D004204:Joint Dislocations / Q000473:pathology*; D008335:Mandibular Condyle / Q000000981:diagnostic imaging / Q000473:pathology*; D010026:Osteosclerosis / Q000000981:diagnostic imaging / Q000473:pathology; D011817:Rabbits; D011897:Random Allocation; D013314:Stress, Mechanical; D013701:Temporal Bone / Q000000981:diagnostic imaging / Q000473:pathology; D019224:Temporomandibular Joint Disc / Q000000981:diagnostic imaging / Q000473:pathology*; D013705:Temporomandibular Joint Disorders / Q000000981:diagnostic imaging / Q000473:pathology*; D055114:X-Ray Microtomography / Q000379:methods