Biochemical Responses of Anodized Titanium Implants with a Poly(lactide-co-glycolide)/Bone Morphogenetic Protein-2 Submicron Particle Coating. Part 2: An In Vivo Study

Purpose: A biochemical approach to implant surfaces can improve bone growth, resulting in desirable boneimplant interfaces. This study was conducted to identify the effect on osseointegration of direct coating of titanium (Ti) implants with poly(D,L-lactide-co-glycolide)(PLGA)/recombinant human bone morphogenetic 2 (rhBMP-2) submicron particles by electrospray. Materials and Methods: Anodized Ti implants were used as a control group, and implants coated with 80 μL of PLGA/rhBMP-2 (50 μg/mL rhBMP-2 per implant) submicron particles by electrospray were used as the experimental group in an in vivo rabbit tibia model. After 3 or 7 weeks of healing, specimens were obtained and prepared for histologic and histomorphometric analyses. Results: The implant surface coated with submicron PLGA/rhBMP-2 showed new bone growth in the apical direction earlier than control implants. In the experimental group at 3 weeks, the bone-to-implant contact ratio and bone area of the three best consecutive threads were significantly higher than those in the control group. However, there was no significant difference between groups at 7 weeks. Conclusion: Within the limitations of this study, the PLGA/rhBMP-2-coated implants facilitated osseointegration between bone and the Ti surface during the early healing phase. Keywords: anodized implant, electrospray, implant coatings, osseointegration, polylactic polyglycolic acid, recombinant human bone morphogenetic protein 2, submicron particle