This study was planned to evaluate the efficacy of surgical treatment in stage 2 medication related osteonecrosis of jaw(MRONJ) patients. Retrospective analysis was performed about patients who were treated with medication related osteonecrosis of jaw from 2015 to 2017. 25 Patients were treated by a single surgeon at the Department of Oral Surgery, Dental Hospital, Pusan National University. The treatment methods they received were conservative or surgical. The results of treatment were classified as "fail" and "success" and the prognosis according to the treatment method was compared. Conservative treatment 14.29% (2 cases), sequestrectomy 64.29% (9 cases) and saucerization 21.43% (3 cases) were performed in the MRONJ group, and 2 treatment failures were encountered after conservative treatment and 1 after saucerization. Surgical treatment resulted in better outcomes in stage 2 MRONJ patients. Furthermore, treatments were deemed successful when surrounding necrotic bone containing sequestrum was reliably removed. Therefore, this study suggests that the treatment of "stage 2" MRONJ should actively consider surgical treatment.

Osteonecrosis is defined as non-vital bone tissue as a result of abnormal process of osseous healing, and is caused by several reasons such as infection, radiation, and medication. Osteomyelitis, osteoradionecrosis, and medication related osteonecrosis of the jaws (MRONJ) which have necrotic bone in common are confused clinically due to similar symptoms and radiographic findings, and are difficult to diagnose definitively. Because each disease represents a separate clinical progress and requires a different treatment approach, it is very important to distinguish each disease. The aim of this study was to analyze the histopathologic features of osteomyelitis, osteoradionecrosis, MRONJ and to understand their different pathogenesis.