title: The effects of gradually induced backward movement of the mandible by a Twin Inclined Plane Device in rats.
abstract: OBJECTIVE
  To develop a model of gradually induced backward movement of the mandible under normal masticatory action and to examine morphological changes in the mandible and condylar cartilage in rats.
  
  
  METHODS
  The newly developed Twin Inclined Plane Device (TIPD) was composed of upper and lower posterior metal crowns with a long inclined plane on both sides separately and was applied in experimental groups of 6-week-old male Wister rats. After 3, 14, 30, and 60 days, the rats were euthanatized and samples were collected. Various measurements and hematoxylin-and-eosin stains were performed.
  
  
  RESULTS
  From day 30 on, the length of the condylar process was shorter in the TIPD groups than in the control groups (P < .05). The angulation of the condylar process axis to the mandibular plane was greater in the TIPD groups (P < .01). The thickness of the condylar cartilage in the posterior part of the posterior region was thinner in the TIPD groups (P < .05) on day 30 and even thinner (P < .01) on day 60; from day 30 on, the thickness in the anterior part of the posterior region was thicker in the TIPD groups (P < .01).
  
  
  CONCLUSIONS
  TIPD can successfully induce backward movement of the mandible under normal masticatory action. TIPD can cause region-specific changes in condylar cartilage and leads to a continuous remodeling.
authors.affiliation: The State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) and Key Laboratory of Oral Biomedicine Ministry of Education, School & Hospital of Stomatology, Wuhan University, Wuhan, China.
authors.forename: Xianming
authors.initials: X
authors.lastname: Hua
authors.forename: Hui
authors.initials: H
authors.lastname: Xiong
authors.forename: Guangli
authors.initials: G
authors.lastname: Han
authors.forename: Xiangrong
authors.initials: X
authors.lastname: Cheng
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D002356:Cartilage / Q000502:physiology; D017267:Dental Prosthesis Design / Q000379:methods*; D008297:Male; D008334:Mandible / Q000033:anatomy & histology / Q000502:physiology*; D008335:Mandibular Condyle / Q000033:anatomy & histology*; D051381:Rats; D017208:Rats, Wistar; D013704:Temporomandibular Joint / Q000502:physiology*