RESUMO
STATEMENT OF THE PROBLEM: Various researchers have suggested the use of ß2-adrenergic receptor antagonists in prevention or treatment of bone resorption. PURPOSE: This study aimed to evaluate the effect of ß2-adrenergic receptor antagonists on number of osteoclasts and osteoblasts involved in the healing of extraction socket of maxillary first molar in rats. MATERIALS AND METHOD: Maxillary first molars of 40 rats were extracted and divided into two groups. The test group received 0.1 mg/kg propranolol intraperitoneally daily. The controls received normal saline. At days 7, 14, 21 and 28 post-extraction, 5 rats were euthanized from each group. Maxillary bone was resected and the mean number of osteoblasts and osteoclasts in tooth socket was measured. RESULTS: After 1 week, the number of osteoclasts in the controls was significantly higher than the test group. A significant increase in the number of osteoclasts in both groups at week 1 was observed compared to the following weeks (p< 0.05). The number of osteoblasts in the controls at second week reached its maximum rate but stayed constant in the 3rd and 4th weeks. Osteoblasts in the test group increased similar to the controls but reached its maximum at 3rd week and showed a significant increase compared to the controls (p< 0.05). CONCLUSION: ß2 adrenergic receptor antagonists decrease the number of osteoclasts and increase the number of osteoblasts during extraction socket healing.