Incidence of antiresorptive agent-related osteonecrosis of the jaw: A multicenter retrospective epidemiological study in Hyogo Prefecture, Japan.

Background/purpose: The incidence of medication-related osteonecrosis of the jaw is increasing worldwide, mostly due to the use of antiresorptive agents (ARAs) such as bisphosphonate (BP) and denosumab (Dmab). However, the proportion of BP-related osteonecrosis of the jaw (BRONJ) and Dmab-related osteonecrosis of the jaw (DRONJ) among all ARA-related osteonecrosis of the jaw (ARONJ) cases is not clear; this hinders appropriate treatment, recurrence-prevention planning, and avoidance of unnecessary Dmab withdrawal. Moreover, the causative drug administered at each disease stage remains unknown. Therefore, we conducted a retrospective study of patients with ARONJ who visited oral and maxillofacial surgery departments at hospitals in Hyogo Prefecture, Japan, over 3 years to classify and compare patient characteristics with those having BRONJ and DRONJ. We sought to identify the proportion of DRONJ in ARONJ. Materials and methods: After excluding stage 0 patients, 1021 patients were included (471 high-dose; 560 low-dose). ARA treatment for bone metastases of malignant tumors and multiple myeloma was considered high dose, while that for cancer treatment-induced bone loss and osteoporosis was low dose. Results: Low doses of BP and Dmab accounted for >50% patients; the results differed from those in other countries. DRONJ accounted for 58% and 35% of high-dose and low-dose cases, respectively. Stage 3 ARONJ cases comprised 92 (19.5%) low-dose BRONJ, 39 (20.1%) high-dose BRONJ, 24 (30%) low-dose DRONJ, and 68 (24.5%) high-dose DRONJ. Eighty-nine patients who received switch therapy were divided into BRONJ or DRONJ, but there was no difference in the ratio of each stage compared to the non-switch therapy. Conclusion: To the best of our knowledge, this is the first study to clarify the proportion of BRONJ and DRONJ cases, causative drug, and its doses by disease stages. DRONJ accounted for approximately 30% of the ARONJ, approximately 60% of which was due to high doses.

[Combination chemotherapy of S-1, docetaxel and CDDP produces a remarkable response in a patient with metastases of supraclavicular lymph nodes and gingival carcinoma of the mandible].

We report a 53-year-old female patient with an unresectable metastasis to the supraclavicular lymph node from a primary gingival carcinoma of the mandible. The patient had a history of tongue carcinoma and had undergone a radical neck dissection for the treatment of gingival carcinoma. She underwent combined chemotherapy consisting of S-1 (80 mg on days 1-14, followed by a 7-day rest), docetaxel (35mg/m2 by intravenous infusion on days 1 and 8), and CDDP (10mg/m2 by intravenous infusion on days 1 and 8) every 3 weeks. After three courses of the above chemotherapy regimen, a computerized tomography examination revealed a complete response. The patient did not experience any severe side effects during the course of chemotherapy. Combined S-1, docetaxel, and CDDP chemotherapy can thus be effective for unresectable recurrences of oral cancer in lymph nodes.

Influence of aging on tooth eruption: experimental canine mandibular allograft.

PURPOSE: Aging is clinically related to tooth eruption; however, there are no known studies that have elucidated the relationship. We examined whether tooth eruption would occur normally in a mature subject. MATERIALS AND METHODS: Using vascularized composite tissue mandibular transplantation, we extracted portions of immature mandibles including the tooth germs from young beagle dogs and placed them into unrelated immature and mature beagle dogs. We then examined eruption of the lower first molar in the grafted mandibular bone and compared the results clinically, radiographically, and histologically. RESULTS: Normal tooth eruption was observed in the transplanted mandibles in the young dogs. In the mature dogs, eruption from the gingiva was delayed, whereas that from alveolar bone occurred normally in the transplanted mandibles. Further, the whole crown was covered with a cap of gingival tissue in the mature dogs, although this cap was not gingival overgrowth. CONCLUSIONS: Tooth eruption is influenced by some unknown factors related to aging. Apparently, apoptosis did not occur in the connective tissues between the reduced enamel epithelia and oral epithelia that overlay the teeth in the mature subjects.