Background: Methods: Results: Conclusion:

: Medication-related osteonecrosis of the jaw (MRONJ) is an adverse event that may inhibit the treatment of primary disease and remarkably influence the patient's quality of life. The treatment methods for MRONJ, nonsurgical and surgical, are controversial, with no agreement as to which method provides the best outcome and should therefore be recommended. This multicenter retrospective study aimed to investigate the treatment methods and outcome in a large number of patients with MRONJ in Japan, utilizing propensity score matching analysis. A total of 361 patients with MRONJ, at eight hospitals, were registered in this study retrospectively. Various demographic and treatment-related variables were examined and analyzed to determine their correlation with the treatment outcome. After propensity score matching for treatment methods (nonsurgical versus surgical treatment), 176 patients were analyzed by logistic regression. It was shown that those with low-dose administration of an antiresorptive agent and surgical treatment had better outcomes. Furthermore, in 159 patients who underwent surgical treatment, those who underwent extensive surgery experienced significantly better treatment outcomes than those who underwent conservative surgery. This is the first study to compare treatment methods for MRONJ using propensity score matching analysis. The results indicated that extensive surgical treatment should be performed as first-choice therapy for patients with MRONJ. © 2017 American Society for Bone and Mineral Research.

Lower third molar extraction is the most common surgical treatment among routine dental and oral surgical procedures. while the surgical procedures for lower third molar extraction are well established, the difficulty of tooth extraction and the frequency of postoperative complications differ depending on the patient’s background. To establish a management protocol for the lower third molars, the prevalence of and risk factors for postoperative complications after lower third molar extraction were investigated in a large number of Japanese patients in a multicenter prospective study. During 6 consecutive months in 2020, 1826 lower third molar extractions were performed at the 20 participating institutions. The medical records of the patients were reviewed, and relevant data were extracted. The prevalence of and risk factors for postoperative complications were analyzed. The prevalence of postoperative complications after lower third molar extraction was 10.0%. Multivariate analysis indicated that age (≤32 vs >32, odds ratio [OR]: 1.428, 95% confidence interval [95% CI]: 1.040–1.962, P < .05), the radiographic anatomical relationship between the tooth roots and mandibular canal (overlapping of the roots and canal vs no close anatomical relationship between the roots and the superior border of the canal, OR: 2.078, 95% CI: 1.333–3.238, P < .01; overlapping of the roots and canal vs roots impinging on the superior border of the canal, OR: 1.599, 95% CI: 1.050–2.435, P < .05), and impaction depth according to the Pell and Gregory classification (position C vs position A, OR: 3.7622, 95% CI: 2.079–6.310, P < .001; position C vs position B, OR: 2.574, 95% CI: 1.574–4.210, P < .001) are significant independent risk factors for postoperative complications after lower third molar extraction. These results suggested that higher age and a deeply impacted tooth might be significant independent risk factors for postoperative complications after lower third molar extraction.