title: Guided bone regeneration of large mandibular defects in a primate model.
abstract: BACKGROUND
  An earlier publication from our laboratory described the use of guided bone regeneration to fill large bone voids in the mandible created through en bloc resection in primates. The present report is an embellishment of this paper and describes bone regeneration experiments in 18 adult male Macaca mulatta monkeys to determine how long membranes must be in position to promote guided bone regeneration.
  
  
  METHODS
  Thirty-six lesions were created in the mandibles of 18 monkeys in a standardized mandibular defect of 8 x 19 mm. Reinforced ePTFE membranes were placed in the animals and held in place with mini screws and sutures for anywhere from 1 to 12 months. No material was added to the defect. In addition to clinical studies, digital subtraction radiology and fluorescent labeling with tetracycline and histomorphometry are described.
  
  
  RESULTS
  The results indicate that no bone gain was observed in membranes exposed for 1 month or less, but bone gain (approximately well over 90% of defects) was observed at 12 months when membranes were left in situ for 2 to 12 months (P <0.0001). No significant difference in the amount of bone gained at 12 months was observed for membranes left in place for intervals ranging from 2 to 12 months. A significant correlation between the amount of bone gain observed at 3 and 12 months was observed (P <0.0001).
  
  
  CONCLUSIONS
  Data therefore suggest that membranes left in situ for 1 month or less result in minimal bone gain compared with membranes left in place from 2 to 12 months. In addition, labeling and stained sections clearly showed that the bone produced after 2 months of membrane placement is mature.
authors.affiliation: Emory University, Yerkes Regional Primate Research Center, Atlanta, GA, USA.
authors.forename: M E
authors.initials: ME
authors.lastname: Fritz
authors.forename: M K
authors.initials: MK
authors.lastname: Jeffcoat
authors.forename: M
authors.initials: M
authors.lastname: Reddy
authors.forename: D
authors.initials: D
authors.lastname: Koth
authors.forename: L D
authors.initials: LD
authors.lastname: Braswell
authors.forename: J
authors.initials: J
authors.lastname: Malmquist
authors.forename: J
authors.initials: J
authors.lastname: Lemons
mesh_terms: D000818:Animals; D001861:Bone Regeneration / Q000502:physiology*; D005456:Fluorescent Dyes; D048091:Guided Tissue Regeneration / Q000379:methods*; D008253:Macaca mulatta; D008297:Male; D008334:Mandible / Q000000981:diagnostic imaging / Q000601:surgery*; D008567:Membranes, Artificial; D023421:Models, Animal; D019647:Oral Surgical Procedures / Q000379:methods*; D011138:Polytetrafluoroethylene; D011859:Radiography; D013382:Subtraction Technique; D013997:Time Factors
chemical_list: D005456:Fluorescent Dyes; D008567:Membranes, Artificial; D011138:Polytetrafluoroethylene