Effect of continuous and intermittent sodium alendronate oral dosing on post-extraction alveoli healing in rats.

OBJECTIVE

This study aimed to compare alveolar healing after tooth extraction in two experimental rat models using continuous or discontinuous dosing of sodium alendronate (ALN).

DESIGN

Forty-eight male Wistar rats were divided into eight experimental groups (n = 6/group) and administered ALN (2.5, 5.0, or 7.5 mg/kg) by gavage, weekly, either intermittently or following a continuous regimen (2.5, 5.0, or 7.5 mg/kg) before tooth extraction. The positive control rats were administered zoledronic acid (ZA; 0.2 mg/kg, intravenous), whereas negative control rats received sterile saline (0.9% NaCl, gavage).

RESULTS

Only the ZA-treated animals showed a larger radiolucent extraction site area compared to the saline group (p = 0.007). Small areas of bone tissue filling the alveoli were visualized in the 7.5 mg/kg continuous ALN group and compared with the saline group (p < 0.001). Increased amounts of empty osteocyte lacunae (p < 0.001) and osteoclasts with signs of apoptosis (p = 0.004) were observed in the continuous ALN groups (2.5, 5.0, and 7.5 mg/kg) compared with the saline group. Increased immunolabeling for TNF-α was observed in the 7.5 mg/kg discontinuous ALN group and all continuous ALN groups compared with the saline group (p < 0.001). The number of tartrate-resistant acid phosphatase (TRAP)-positive osteoclasts was higher in the two continuous ALN groups (5.0 and 7.5 mg/kg) than in the saline group (p < 0.001).

CONCLUSIONS

Continuous administration of ALN impaired post-extraction alveolar bone healing in rats; however, discontinuation of ALN administration before tooth extraction allowed for adequate post-dental extraction alveolar healing.