Abstract: AIM: To investigate the impact of alendronate on bone resorption of normal and ovariectomized rats at the bone-screw interface through radiographic and histologic findings. METHODS: Thirtytwo female Wister rats with a mean body weight of 332 g (287-351 g) were divided into four groups at random. Rats in group C and D were ovariectomized. 8 weeks later, the proximal one-third of the left tibia of all rats were inserted into self-drilling mini cortical screws. After operations, alendronate were used in group A and C and saline were given in group B and D. The rats were euthanized at 5 weeks after screws having been attached. Radiographic and histologic findings subsequently were analyzed. RESULTS: Radiographs confirmed that no osteolytic area was present around screws immediately after insertion, whereas 5 weeks after insertion, a wide and low-density area corresponding to the screw hole was evident in the saline groups compared with the alendronate groups. On histologic observation, the width of the fiber membrane and the number of TRAP-positive cells were decreased in the alendronate groups than those in the saline groups, and the difference was statistically significant. CONCLUSION: Alendronate effectly inhibits bone resorption of either normal or ovariectomized rats at the bone-screw interface in rats.

Key words: rats, alendronate, fiber membrane for absorption, tartrate-resistant acid phosphatase