Incorporation of bone morphogenetic protein 2 (BMP-2) on dental implants

Introduction: Dental implant is nowadays a common undertaking, the more rapidly an implant becomes osseointegrated, the shorter will be the time of convalescence, the lower the risk of infection and the lower the costs for the patient. We have recently shown that BMP-2 can be incorporated in a dose-dependent manner into biomimetic octacalcium phosphate coatings on titanium implants. The incorporated BMP-2 underwent gradual release (over a period of weeks) into the surrounding milieu wherein it retained its biological activity. In an ectopic rat model, BMP-2 released from implant coatings accelerated the formation of bone tissue not only upon the implant surface but also within its immediate surrounds. Objective: It was the purpose of the present study to ascertain whether BMP-2 can be incorporated into biomimetic coatings on dental implants, accelerate the bone formation and enhance osseointegration.

Methods: Dental implants were pre-coated biomimetically with a thin layer of calcium phosphate and then incubated in a supersaturated solution of calcium phosphate containing BMP-2 at a concentration of 10 mg/ml, under physiological conditions for 48 hours. Coated implants then underwent SEM, immunohistochemical evaluation, and FTIR and XRD analysis. The quantity of BMP-2 taken up by coatings was monitored colorimetrically.

Results: Dental implants were uniformly coated with a layer of 30-50 mm thick calcium phosphate coatings, in which BMP-2 was incorporated. SEM revealed coatings prepared in the absence of protein to be composed entirely of straight, plate-like units with sharp edges. Crystal geometry did not change as a function of BMP-2 within the solution. There was 3.65 mg of calcium phosphate coating material obtained from each implant at a BMP-2 concentration of 0.5mg/mg in the coating.

Conclusion: BMP-2 can be incorporated into biomimetic coatings of dental implants. We currently investigate the osseointegration potential of such implant in a miniature pig model.