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Background/purpose: Tooth extraction has been avoided in patients receiving antiresorptive agent (ARA) therapy. This study aimed to investigate dental findings associated with medication-related osteonecrosis of the jaw (MRONJ) development in patients. Materials and methods: First, in patients treated with high-dose ARAs, the relationship between dental findings and MRONJ development was examined. Next, in patients with MRONJ undergoing surgery, the relationship between dental findings and MRONJ occurring at a site distant from the initial site was examined. Results: MRONJ occurred in 13 of 172 patients (80 of 3725 teeth) during observation. Multiple tooth loss, periodontal ligament space enlargement, alveolar bone loss, periapical osteosclerosis, and local infection symptoms were associated with MRONJ development. Tooth extraction significantly reduced MRONJ development. Regarding other-site recurrence, new MRONJ developed at other sites in 54 of 357 patients with MRONJ (171 of 5038 teeth). Multiple tooth loss, apical lesions, periodontal ligament space enlargement, and periapical osteosclerosis were significantly associated with MRONJ development. In patients with malignant tumors, tooth extraction significantly reduced the subsequent incidence of MRONJ, while in patients with osteoporosis, there was no difference in the incidence of MRONJ between patients with and without tooth extraction. Conclusion: MRONJ was more likely to develop from teeth with local infections. Extraction of teeth with local infection in patients with malignancy may be more effective than tooth preservation in preventing MRONJ.

Background /purpose: The standard treatment for medication-related osteonecrosis of the jaw (MRONJ) is surgery. However, reports on the appropriate extent of bone resection are few. We aimed to examine the relationship between the extent of bone resection and postoperative outcomes in patients with mandibular MRONJ. Materials and methods: The clinical and imaging findings and treatment outcomes of 206 patients (258 surgeries) with mandibular MRONJ undergoing surgery were reviewed. Imaging findings were evaluated using computed tomography (CT) to sequestrum, osteolysis, periosteal reaction, and mixed-type osteosclerosis, and determine the extent of resection. In some cases, samples were taken from within the bone, and real-time polymerase chain reaction was used to confirm the presence of bacteria and fungi. Results: The three-year cumulative cure rate was 81.7%. Patients with malignant tumors showing no osteolysis and undergoing sequestrum removal or marginal mandibulectomy had significantly worse prognosis than those with osteoporosis showing osteolysis and undergoing segmental mandibulectomy. Furthermore, patients with residual osteolysis, periosteal reactions, and mixed-type osteosclerosis on CT were more likely to develop recurrence. Eleven patients showed no osteolysis on CT images. Patients with cancer administered with high-dose denosumab had significantly poorer prognosis. Bacteria and fungi were also detected in samples obtained from gap-type periosteal reaction and mixed-type osteosclerosis. Conclusion: Surgery for MRONJ requires resection of the infected bone. Aside from the osteolysis area, the gap-/irregular-type periosteal reaction and mixed-type osteosclerosis must also be included in the resection area. Methods for determining the extent of bone resection in MRONJ without osteolysis are a future challenge.

Background/purpose: Although mandibular advancement oral appliances (OAs) are the most widely used and accepted therapeutic modality for obstructive sleep apnea (OSA), whether these maxillary and mandibular appliances should be semi-fixed or fixed remains uncertain. This randomized crossover pilot study compared the efficacy, side effects, and patient preference of semi-fixed and fixed OAs for the treatment of OSA. Materials and methods: Patients with mild to moderate OSA were recruited and randomly assigned to either the semi-fixed or fixed OA group, whereby they used their assigned OA for the first 4 weeks, followed by assessments for sleep parameters (including the Apnea-Hypopnea Index [AHI]) and temporomandibular joint pain as a side effect. After a two-week washout period, patients were switched to the alternative OA for 4 weeks, followed by repeated assessments. Patient preference was assessed at the end of the completed treatment period. Results: Fifteen patients were enrolled and completed the full study protocol. Both types of OAs were efficient in reducing the patient's AHI in comparison to baseline (i.e., without OA). However, there was no significant difference in AHI reduction between the semi-fixed and fixed OA devices. Regarding the side effect of temporomandibular joint pain and patient preference, the semi-fixed OA device was superior to the fixed OA device on both measures. Conclusion: While both semi-fixed and fixed OAs are effective in treating patients with OSA, semi-fixed OAs are superior in regards to both patient preference and reduced side effects. Thus, semi-fixed OAs may be the preferred therapeutic modality for OSA.