Effectiveness of local delivery of alendronate in reducing alveolar bone loss following periodontal surgery in rats

Background: Mucoperiosteal flaps are used to access bone and root surfaces for debridement, packet elimination management of periodontal defects, and in regenerative procedures, as well as in implant surgery. Many reports sho w that periodontal surgery stimulates osteoclast activity with varying amou nts of alveolar bone loss. Alendronate given intravenously significantly re duced alveolar bone loss in mucoperiosteal flap procedures. In the present study, we explored the effectiveness of different concentrations of alendro nate, delivered at the surgical site at the time of surgery, in distant del ivery in reducing alveolar bone loss. Methods: Following elevation of a mucoperiosteal flap next to molars of the rat mandible, a gelatin sponge soaked with different concentrations of ale ndronate (0, 1, 5, 20, or 40 mg/ml; experiment A) was applied to exposed bo ne on the experimental side. In the second group (experiment B), alendronat e (0, 50, 200, or 400 mug) was topically delivered in the cheek submucosa o n the left side (distant to the surgical site) in a small cut into which th e gelatin sponge soaked with the drug was placed. Results: Topical application of 200 mug and 400 mug doses of alendronate at the time of surgery was significantly effective (P <0.001) in reducing bon e loss. Generally the percentage of sections with mild bone loss (V1, V2) i ncreased with an increase in the dose of alendronate, while the percentage of sections with severe bone loss (H1, H2) decreased with an increase in al endronate dose. Topical application of 400 <mu>g of alendronate had a syste mic effect. Conclusions: This study implies that topical delivery of alendronate at the time of surgery reduces bone loss in periodontal procedures involving muco periosteal flap surgery. The mast effective dose is 200 mug for topical del ivery at the surgical site and 400 mug for distant sites.