Implant system for guiding a new layer of bone. Computed microtomography and histomorphometric analysis in the rabbit mandible

Abstract

To prove the concept that an implant system with osteoconductive surface characteristics and an osteoinductive scaffold material has the capacity to guide vertical supracrestal bone growth in a rabbit mandible onlay model. Thirteen adult white New Zealand rabbits each received custom-designed dental implants. All implants had sandblasted, acid-etched (SLA) surfaces, with the coronal aspect (3 mm) of each implant was left outside the lateral aspect of posterior mandibular bone, but covered by periosteum, muscle, subcutaneous tissue, and skin. Bone formation around implants placed adjacent to osteoinductive demineralized bone matrix (DBM) scaffolds were compared with contralateral implants without scaffolds in six rabbits using micro-CT imaging. Bone formation around implants with scaffolds from seven additional rabbits was measured using both micro-CT imaging and quantitative histology. At 8 weeks, new supracrestal bone was seen adjacent to all implants placed with DBM and two implants without DBM. The mean supracrestal bone heights achieved for implants with and without DBM scaffolds as measured by micro-CT was 2.1+/-0.9 and 0.8+/-0.9 mm, respectively (P=0.008). Histomorphometric analysis illustrated that supracrestal bone-to-implant contact for implants with DBM scaffolds was 58.1+/-14% and that mean supracrestal bone height was 2.4+/-0.6 mm. Successful implant-guided supracrestal osteogenesis has been demonstrated in a rabbit model with the combined use of osteoconductive implant surfaces, an osteoinductive scaffold, and a device that prevents soft tissue downgrowth and provides scaffold stabilization.