Effects of alendronate on the removal torque of implants in rats with induced osteoporosis.

PURPOSE In this study, the removal torques of commercially pure titanium Implants that had been implanted simultaneously with the start of treatment for osteoporosis were compared to those of a group without treatment and a healthy group. MATERIALS AND METHODS Rats treated by ovariectomy or sham surgery at the age of 12 weeks were used. Twenty-eight days after surgery, the rats treated by ovariectomy were divided into an alendronate-treated group and an untreated (ovariectomy-control) group. At the start of administration of alendronate, a titanium implant was placed in the distal metaphysis of the femur. After 1 month of administration of alendronate and a vehicle, removal torque, the percentage of bone-implant contact (BIC), and parameters of treatment using alendronate were measured. RESULTS The removal torque values were 10.1 +/- 1.6 Ncm for the group of osteoporotic rats that had been administered alendronate and 6.4 +/- 1.0 Ncm for the group of osteoporotic rats that did not receive alendronate, indicating that the removal torque was significantly higher in the former group than in the latter group. However, there was no significant difference between the alendronate-treated group and the healthy control group (ie, sham surgery) (9.3 +/- 1.3 Ncm). DISCUSSION AND CONCLUSION These results suggested that implant placement together with treatment of osteoporosis is possible in the ovariectomized rat model.