An Evaluation of Bone Induction Delivery Materials in Conjunction with Root-Form Implant Placement

The success of bone-inductive cytokines in surgical alveolar defects is greatly dependent upon the ability of carrier materials to effectively deliver the inductive protein to the surgical site. An evaluation of three types of carrier materials was undertaken in six monkeys using an osseous defect of 2.0 cm that was produced by partial resection of the maxilla and mandible and placement of titanium implants in each alveolar quadrant. After 5 months, abutments were placed on the implants, which were allowed to function for an additional 5 months. Intravital labeling with tetracycline was used to evaluate the late healing remodeling processes. The carriers were evaluated by studying (1) the amount of surface osseointegration on the root-form implants; (2) the bone density as related to trabecular pattern and cortex formation; and (3) the quantitative and qualitative thickness of the alveolar bone buccolingually at the implanted sites. Of the three materials, the calcium carbonate coral (BioCoral) produced a decreased amount of bone regeneration in comparison with both the poly(methylethyl methacrylate) material (HTR) and the porous bone mineral (Bio-Oss). Both the HTR and Bio-Oss with rhBMP-2 produced excellent thickness of the repaired alveolar ridge. All three materials produced the same amount of osseointegration with the titanium implant surfaces. Good bone quality, as reflected in thickening of the trabecular bone patterns, was seen with both Bio-Oss and HTR. While all three of these carrier materials appeared to produce good osseointegration with the titanium implants, BioCoral did not effect a quantitative or qualitative restoration of the alveolar bone comparable to that following the use of either HTR or Bio-Oss with rhBMP-2.