Influence of alendronate administration regimen on the final outcome of implant osseointegration in an osteoporotic model.

Abstract This study aimed to evaluate the bone response around titanium implants in osteoporotic rabbits receiving oral alendronate (ALN) for one month either simultaneously with implant placement (IP) or stopped immediately before surgery. Six weeks before IP, 34 adult female New Zealand white rabbits were submitted to intramuscular injections of dexamethasone (3 mg/kg twice a week) to induce osteoporosis-like conditions. Two animals were sacrificed and histological examinations of their leg bones were performed to confirm the osteoporosis-like condition, as compared to a healthy animal. The remaining 32 rabbits were then divided into four equal groups. Group I represented osteoporosis-like animals receiving implants. For Groups II, III and IV, osteoporosis-like animals received calcium phosphate cement before IP. Animals in Group II received implants without any systemic treatment for osteoporosis. In Group III, ALN was simultaneously started with IFP. In Group IV, ALN was stopped immediately before surgery. At 12 weeks post-surgery all animals were sacrificed. Both bone-implant interface and mineralized bone area percentage (MBA%) were microscopically evaluated. Group IV showed a significant gain in MBA% (p < 0.05), along with the most favorable implant integration outcome. Our results suggest that finishing an ALN course before implant placement could enhance the healing capacity around implants.