Objectives: The purpose of this study was to evaluate the effect of alendronates on healing of extraction sockets and healing around implants in the maxilla of rats. Materials and Methods: Twenty-four Sprague-Dawley rats were used. The rats in bisphosphonate group were subcutaneously injected with alendronate (5.0mg kg --1 ) three times a week for 4weeks. Both sides of the maxillary first molars were extracted, and customized titanium implants (Ø1.5×2.0mm) were placed immediately into one side. Rats were killed at 3, 7, 14, or 28days following surgery. Results: New bone formation in extraction sockets, bone area around the implant site, and bone-implant contact were not delayed in the bisphosphonate group. The tartrate-resistant acid phosphatase positive cell count did not differ between bisphosphonate and control groups; however, empty lacunae were observed significantly more in bisphosphonate group. The differences in empty lacunae were shown at different time points between the implant sites and extraction sites: at 7days after extraction, and at 14 and 28days after implantation. Conclusions: Alendronates seemed to decrease bone resorption but not to decrease bone formation. Empty lacunae were observed significantly more at later time points in implant sites compared to extraction sockets.
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