title: Experimental induction of rheumatoid arthritis in temporomandibular joint of the guinea pig: a clinical and radiographic study.
abstract: OBJECTIVE
  To correlate the clinical and radiographic changes at different stages of experimentally-induced rheumatoid arthritis (RA) of the TMJ.
  
  
  METHODS
  Forty eight adult male guinea pigs, aged 4-6 months, were divided into two groups. Arthritis was induced in the experimental animals by intraperitoneal injection of heat-inactivated group A Streptococcus pyogenes. Four animals from each group were sacrificed and examined clinically and radiographically at intervals of 48 h and 1, 2, 4, 6 and 8 weeks.
  
  
  RESULTS
  The main clinical findings were stiffness, crepitation and reduction in mouth opening. Radiographically, the main features were condylar erosion, flattening and sclerosis subcortical cyst formation.
  
  
  CONCLUSIONS
  RA passes through stages that can be correlated clinically and radiographically. Both the clinical and radiographic manifestations in this experimental model are comparable with those previously reported in the small joints of humans.
authors.affiliation: Department of Maxillofacial Surgery and Diagnostic Sciences, College of Dentistry, King Saud University, Riyadh, Saudi Arabia.
authors.forename: A F
authors.initials: AF
authors.lastname: al-Mobireek
authors.forename: A M
authors.initials: AM
authors.lastname: Darwazeh
authors.forename: M B
authors.initials: MB
authors.lastname: Hassanin
mesh_terms: D000818:Animals; D001172:Arthritis, Rheumatoid / Q000000981:diagnostic imaging / Q000503:physiopathology*; D002473:Cell Wall; D004195:Disease Models, Animal; D005500:Follow-Up Studies; D006168:Guinea Pigs; D006358:Hot Temperature; D006801:Humans; D007274:Injections, Intraperitoneal; D008297:Male; D008334:Mandible / Q000503:physiopathology; D008335:Mandibular Condyle / Q000000981:diagnostic imaging; D009068:Movement; D010026:Osteosclerosis / Q000000981:diagnostic imaging; D016059:Range of Motion, Articular / Q000502:physiology; D013297:Streptococcus pyogenes; D013705:Temporomandibular Joint Disorders / Q000000981:diagnostic imaging / Q000503:physiopathology*; D014056:Tomography, X-Ray