The effect of topical delivery of novel bisacylphosphonates in reducing alveolar bone loss in the rat model

Background: Periodontal surgery stimulates osteoclast activity, leading to varying amounts of alveolar crest loss. We have established that topical ap plication of 20 mg/ml of alendronate placed at the surgical mucoperiosteal site produced a striking reduction of alveolar bone loss in the rat model. The aim of this investigation;was to examine the antiresorptive efficacy of 3 novel bisacylphosphonates topically delivered at the surgical site, in c omparison to alendronate and etidronate which are in clinical use. Methods: Mucoperiosteal flap (MF) surgery was; performed on the buccal and lingual aspects next to molars on both sides of the rat mandible. A gelatin sponge soaked in the bisphosphonate solution prepared by dissolving 20 mg of the bisphosphonate (alendronate, etidronate, VS-5, VS-6, ISA-13, SuBP) i n 1 mi of saline was applied to exposed bone on the right side of the mandi ble (experimental, MF + BPs) and the left, side was treated with saline onl y (control, MF + S). Sections were evaluated for bone loss using microradio graphy pattern and amount. Results: The 3 novel bisacylphosphonates, VS-5 VS-6, and ISA-13 were more e ffective than etidronate, and less effective than alendronate, The most eff ective among this group was ISA-13 followed by VS-5 and VS-6, Conclusion: We conclude that ISA-13-like alendronate is effective in reduci ng alveolar bone loss when delivered at surgical sites. Since ISA-13 is wel l absorbed through mucose tissues, we suggest that ISA-13 efficacy on reduc ing bone loss should be tested by its application on the mucosal tissue.