Qualitative Analysis of Peripheral Peri‐Implant Bone and Influence of Alendronate Sodium on Early Bone Regeneration

Background: Alendronate sodium increases alveolar bone density with systemic use. It inhibits osteoclast activity and is thought to result in a net increase in osteoblastic activity. However, little is known about local in vivo use. The purpose of this study was to evaluate the effect of local delivery of alendronate on bone regeneration within peri‐implant defects. Peri‐implant bone was examined histomorphometrically to evaluate the amount of supporting bone peripheral to the bone‐implant interface. Methods: Six adult hound dogs were evenly divided into 2 groups, with one group receiving alendronate‐coated dental implants and the other group serving as controls. Dental implants were placed immediately after extraction of right and left second, third, and fourth mandibular premolars. Forty‐eight dental implants were placed (2 types in each dog: 24 hydroxyapatite [HA]‐coated and 24 titanium machine‐polished [TMP]), for a total of 4 variables. A bioabsorbable collagen membrane was secured over the implants and defects, and the flaps closed primarily. The dogs were sacrificed on day 28. Specimens were sectioned, mounted, and stained with Stevenel's blue and van Gieson's picric fuchsin. The amount of bone adjacent and 1 mm peripheral to the implant surface was recorded with a computerized microscopic digitizer. Results: Locally applied alendronate resulted in significantly increased amounts of bone (P