백서에서 발치후 비스포스포네이트 관련 악골 괴사를 예방하기 위한 구강점막의 일차 폐쇄의 효과

Abstract

I. INTRODUCTION Bisphosphonate-related osteonecrosis of the jaw (BRONJ) is defined as the presence of exposed bone in the jaw that does not heal more than 8 weeks in patients who has been bisphosphonates (BPs) treatment history and who has not undergone radiation therapy in the head and neck region. Bisphosphonates inhibit osteoclastic activity, thereby reducing the rate of bone turnover, resulting in compromised bone wound healing. The lack of primary mucosal closure over areas of exposed bone is the key factor in the development of osteonecrosis of jaw. The purpose of this study was to evaluate the effect of primary closure on extraction sockets after injection of zoledronic acid in rats.

Ⅲ. MATERIALS AND METHODS A total of 10 female Sprague-Dawley rats were intramuscularly injected with the zoledronic acid of 0.1mg/kg, 3 times a week for 8 weeks. Then, the maxillary first molars on both sides were extracted. The left extraction site was closed using collagen sponge and absorbable silk (PDS 5-0). The extraction sites were smoothened sharp alveolar bone and sutured to achieve tension-free primary closure. The right extraction site was left without any other treatment. The rats were euthanized after 8 weeks, and the extraction sockets were examined by clinical, radiological, and histological evaluation.

Ⅳ. RESULTS Normal healing of the extraction socket was observed from the experimental group (left side) while the bone exposure was observed from the control group (right side). There were not infections such as pus discharge, gingivitis in both groups. A radiolucency of the extraction socket in the control group could be still seen from the micro-computed tomographic image. In addition, the micro-computed tomographic evaluation revealed that bone fill of the extraction socket with existing radiolucency. Histological findings of the control group showed loss of continuity of the epithelium above the extraction socket and infiltration of inflammatory cell. On the other hands, the healing of the epithelium was completed and normal healing process was observed in experimental group. Consequently, the control group showed delayed healing of tooth extraction socket compared to the experimental group.

Ⅴ. CONCLUSION This study demonstrated that, primary closure on extraction socket has the possibility of a positive effect to prevent BRONJ and wound healing. Further studies are needed in human model and in clinical randomized controlled trial.