title: A histologic study of deformation of the mandibular condyle caused by distraction in a rat model.
abstract: OBJECTIVE
  This study investigated the bone resorption process of the rat mandibular condyle after mandibular distraction.
  
  
  METHODS
  Male Wistar rats at 10 weeks of age underwent unilateral mandibular distraction at 0.175 mm per 12 hours for 10 days. Histologic and histochemical analyses were performed at postoperative day 1 and weeks 1 and 3.
  
  
  RESULTS
  High-resolution computed tomography (micro-CT) observations showed that deformation of the condyle occurred in the anterior region, where a discontinuity of the condylar cartilage layer was found in histologic sections. This destroyed area gathered many osteoclasts. In the central region, disorganization with a thin hypertrophic cell layer was recognizable by day 1 but later thickened. Morphologic recovery of the mandibular condyle could be attained by week 3 in this animal model.
  
  
  CONCLUSIONS
  These morphologic findings indicate that rapid deformation of the condyle, with destruction of the cartilage layer and bone resorption, was caused by artificial distraction.
authors.affiliation: Graduate student, Division of Reconstructive Surgery for the Oral and Maxillofacial Region, Niigata University Graduate School of Medical and Dental Sciences; Research Fellow of the Japan Society for the Promotion of Science, Niigata, Japan. Electronic address: sakagami@dent.niigata-u.ac.jp.
authors.forename: Naoko
authors.initials: N
authors.lastname: Sakagami
authors.affiliation: Professor, Division of Reconstructive Surgery for the Oral and Maxillofacial Region, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan.
authors.forename: Tadaharu
authors.initials: T
authors.lastname: Kobayashi
authors.affiliation: Associate Professor, Division of Oral Anatomy, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan.
authors.forename: Kayoko
authors.initials: K
authors.lastname: Nozawa-Inoue
authors.affiliation: Professor, Division of Biochemistry, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan.
authors.forename: Kimimitsu
authors.initials: K
authors.lastname: Oda
authors.affiliation: Assistant Professor, Division of Reconstructive Surgery for the Oral and Maxillofacial Region, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan.
authors.forename: Taku
authors.initials: T
authors.lastname: Kojima
authors.affiliation: Professor, Division of Oral Anatomy, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan.
authors.forename: Takeyasu
authors.initials: T
authors.lastname: Maeda
authors.affiliation: Emeritus Professor, Division of Reconstructive Surgery for the Oral and Maxillofacial Region, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan.
authors.forename: Chikara
authors.initials: C
authors.lastname: Saito
mesh_terms: D000818:Animals; D015519:Bone Density; D001862:Bone Resorption; D003799:Dental Stress Analysis; D008297:Male; D008335:Mandibular Condyle / Q000000981:diagnostic imaging / Q000254:growth & development* / Q000601:surgery*; D023421:Models, Animal; D019857:Osteogenesis, Distraction / Q000379:methods*; D011897:Random Allocation; D051381:Rats; D017208:Rats, Wistar; D055114:X-Ray Microtomography