Effects of Alendronate on Bone Remodeling Around Osseointegrated Implants in Rats

Objective: To determine the effects of alendronate on bone remodeling around osseointegrated implants in rats. Materials and Methods: The maxillary first molars were extracted from 36 male Sprague-Dawley rats, and replaced with customized implants. They were then administered twice-weekly subcutaneous injections of either alendronate (alendronate group) or saline (control group) after allowing a 4-week period for osseointegration. They were killed at 4, 8, or 12 weeks after the commencement of the injection protocol, and the implant sites were evaluated comprehensively by microcomputed tomographic, histologic, and biochemical assessments. Results: It was hard to find statistically significant differences from microcomputed tomographic analyses. In addition, inconsistent variations were derived from histologic data. However, biochemical data showed statistically significant differences; serum osteocalcin level was statistically significantly lower in the alendronate group than in the control group at 8 weeks after the commencement of injections. In addition, serum osteocalcin level in the alendronate group was statistically significantly lower at 8 and 12 weeks after the initial injection point than at preinjection. Conclusions: The results suggest alendronate might affect bone remodeling activity around osseointegrated implants negatively, and serum osteocalcin could serve as an accessory tool to evaluate this effect.