Implants in regenerated bone in a primate model

Background: Earlier publications from our laboratory described the use of g uided bone regeneration to fill large bone voids in the mandible created th rough en bloc resection in primates. The present report describes placement of implants into the regenerated bone with subsequent prostheses construct ion and loading. Methods: Lesions were created in the mandibles of 9 monkeys in a standardiz ed mandibular defect of 8 x 19 mm. Reinforced expanded polytetrafluoroethyl ene 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 each animal a root-form implant was placed 12 mm distal to the abutment teeth into the regenerated bone and was loaded with a prosthesis f or 12 months. These implants were compared to original implants placed in t he same monkeys years earlier in the same location in non-regenerated bone. Digital radiology and histomorphometry are described. Results: The results show that root-form implants placed in regenerated bon e show the same radiological and histomorphometric characteristics as in no rmal bone when loaded. In addition, the percentage of bone contact with imp lants seen in regenerated bone Versus non-regenerated bone is the same when both are loaded (65 +/- 13% SD in regenerated bone versus 59 +/- 15% SD in non-regenerated bone). Conclusions: In a primate model root-form implants placed in regenerated bo ne and prosthetically loaded show no difference when compared to root-form implants placed in non-regenerated bone and prosthetically loaded.