Abstract
Antiresorptive agents such as bisphosphonate or denosumab have been widely used for patients with osteoporosis or bone metastasis from malignant tumors, but medication-related osteonecrosis of the jaw（MRONJ）sometimes occurs. A retrospective study was conducted on the treatment and prognosis of MRONJ in patients over 80 years old. One hundred and eighty patients（66 patients were 80 years or older and 114 under 80）in three hospitals were enrolled in the study. Differences of background factors, treatment methods, and prognosis between the two age groups were analyzed by Fisherʼs exact test, one-way ANOVA, Kaplan-Meier method, log rank test, and Cox proportional hazard model. Patients over 80 years old had osteoporosis more frequently with longer administration of antiresorptive agent. Most patients underwent surgical treatment in both age groups, and no differences were found in cure rate of the two groups. Three variables of primary disease（osteoporosis/malignant tumor）, treatment method（surgical/conservative）, and periosteal reaction by preoperative CT examination were independent risk factors related to the cure rate, but old age did not influence the treatment outcome. These findings suggest that surgery should be the standard treatment for MRONJ regardless of age, and that a good outcome is expected as young people.
