title: Replacement of the condyle and ascending ramus by a modular endoprosthesis in Macaca fascicularis--part 1: a clinical and radiographic study.
abstract: OBJECTIVE
  To evaluate the feasibility of replacing the condyle and ascending ramus with a novel modular endoprosthesis in Macaca fascicularis.
  
  
  METHODS
  Eight male adult monkeys (Macaca fascicularis) were used in this study. The right condyle and ascending ramus posterior to the lower second molar were resected. An endoprosthesis consisting of 2 modules was inserted to replace the resected segment and fixed in place using polymethylmethacrylate bone cement (Palacos). Four monkeys were sacrificed at 3 months and another 4 at 6 months postoperatively. The operated side of the mandible was then harvested, including the endoprosthesis and the stump of the mandible to which it was attached. Lateral mandibular radiographs were taken using standard settings immediately postoperatively and postsacrifice.
  
  
  RESULTS
  Two monkeys presented with a fistula at the operated area 1 month postoperatively, but this resolved with a short course of antimicrobial treatment. At the time of sacrifice, no fistulas, dehiscences, or mobility of the endoprostheses was observed. There was no significant change in maximum mouth opening. At 3 months, a linear radiolucency was noted at the cement-bone interface in the 2 monkeys that previously presented with fistulas; whereas at 6 months, none of the 4 animals showed any radiolucency.
  
  
  CONCLUSIONS
  The use of a cemented modular endoprosthesis for replacement of the condyle and ramus unit was feasible with minimal complications allowing normal mouth opening and occlusion. Further histologic and microfocus computed tomographic studies will be done to confirm the findings.
authors.affiliation: Department of Oral and Maxillofacial Surgery, National Dental Centre, Singapore, Republic of Singapore. gohbee@starhub.net.sg
authors.forename: Bee Tin
authors.initials: BT
authors.lastname: Goh
authors.forename: Shermin
authors.initials: S
authors.lastname: Lee
authors.forename: Henk
authors.initials: H
authors.lastname: Tideman
authors.forename: Paul J W
authors.initials: PJ
authors.lastname: Stoelinga
mesh_terms: D000818:Animals; D001843:Bone Cements; D002484:Cementation; D005240:Feasibility Studies; D007595:Joint Prosthesis; D008252:Macaca fascicularis; D008297:Male; D008334:Mandible / Q000000981:diagnostic imaging / Q000601:surgery*; D008335:Mandibular Condyle / Q000000981:diagnostic imaging / Q000601:surgery; D008341:Mandibular Prosthesis; D019904:Polymethyl Methacrylate; D011474:Prosthesis Design; D011859:Radiography; D016059:Range of Motion, Articular
chemical_list: D001843:Bone Cements; D019904:Polymethyl Methacrylate