title: Effects of injury or removal of the articular disc on maxillomandibular growth in young rats.
abstract: OBJECTIVE
  This study analyzed the effects of injury and removal of the articular disc on maxillomandibular growth in young rats.
  
  
  METHODS
  Thirty 1-month-old male Wistar rats were divided into 3 groups: injury, removal, and sham operated. Unilateral injury of the articular disc, removal of the articular disc, or only surgical access was performed. The animals were sacrificed at 3 months of age. Specimens were submitted to radiographic incidences and cephalometric mensurations were performed using a computer system. Data were subjected to statistical analyses among groups and between sides in each group.
  
  
  RESULTS
  There were degenerative changes of the condylar process in the injury and removal groups. Significant differences between sides were observed for length of the premaxilla, height of the mandibular body, and length of the mandible. Concomitant group comparisons showed significant differences in the height of the mandibular body (P = .003) and the length of the mandible (P = .001). There were important decreases to the height of the mandibular body and mandibular length in the injury group, whereas there was an important decrease only for the length of the mandible in the removal group. Specific measurements of mandibular ramus structures exhibited differences between the injury and sham-operated groups and between the removal and sham-operated groups.
  
  
  CONCLUSIONS
  Experimental injury and removal of the articular disc during the growth period in rats had deleterious effects on ramus structures and induced asymmetry of the mandible, with worse outcomes resulting from injury to the articular disc.
authors.affiliation: Research Fellow, Department of Oral and Maxillofacial Surgery, School of Dentistry, University of São Paulo, São Paulo, SP, Brazil.
authors.forename: Leandro Giuseppim
authors.initials: LG
authors.lastname: Toledo
authors.affiliation: Graduate Student, Department of Oral and Maxillofacial Surgery, School of Dentistry, University of São Paulo, São Paulo, SP, Brazil.
authors.forename: Samantha Christine X B
authors.initials: SC
authors.lastname: Cavalcanti
authors.affiliation: Associate Professor, Department of General Pathology, School of Dentistry, University of São Paulo, São Paulo, SP, Brazil.
authors.forename: Luciana
authors.initials: L
authors.lastname: Corrêa
authors.affiliation: Full Professor, Department of Oral and Maxillofacial Surgery, School of Dentistry, University of São Paulo, São Paulo, SP, Brazil. Electronic address: jgcluz@usp.br.
authors.forename: João Gualberto C
authors.initials: JG
authors.lastname: Luz
mesh_terms: D000818:Animals; D008297:Male; D008334:Mandible / Q000473:pathology*; D008437:Maxilla / Q000473:pathology*; D051381:Rats; D017208:Rats, Wistar; D019224:Temporomandibular Joint Disc / Q000293:injuries* / Q000601:surgery*