Tooth extraction is reported as the main trigger of bisphosphonate (BP) -related osteonecrosis of the jaw (BRONJ). A method to prevent BRONJ has not been scientifically proven. The American Association of Oral and Maxillofacial Surgeons (AAOMS) differs from the International Task Force on Osteonecrosis of the Jaw with regard to the prevention of BRONJ via prophylactic withdrawal before tooth extraction. We performed a multicenter prospective study regarding the development of BRONJ after tooth extraction in BP-treated patients for the purpose of determining factors associated with the frequency of BRONJ. We extracted teeth from patients with a history of current or prior treatment with BP preparations; teeth were extracted using a common treatment protocol. The presence or absence of BRONJ and adverse events were evaluated. A total of 1,323 cases were targeted for this study; 2,371 teeth were extracted. The overall incidence of BRONJ was 1.74%; in the prophylactic withdrawal group it was 1.73%, whereas in the prophylactic non-withdrawal group it was 1.75%. Factors associated with the onset of BRONJ were sex, preparation adaptation classification, oral hygiene state, site of tooth extraction, and Denosumab usage. From analysis that considered the effect of confounding using the propensity score, prophylactic BP withdrawal did not result in a reduction of BRONJ (onset odds ratio with withdrawal: 1.13, 95%CI 0.36-3.57).

Ameloblastoma is a benign odontogenic tumor with locally aggressive characteristics and a high recurrence rate. The aim of this study was to evaluate the risk factors for recurrence, and to determine the appropriate treatment for ameloblastoma. The study was conducted in the Department of Maxillofacial Surgery, Tokyo Medical and Dental University Hospital, covering the years 1992–2018. The following were recorded and analyzed: patient demographic data, tumor site and maximum tumor size, World Health Organization classification, treatment method, positional relationship between tumor and mandibular canal, whether or not patients had a preoperative biopsy confirmation report, effect of marsupialization, treatment of teeth in contact with the tumor, duration of follow-up, and timing of recurrence. The treatment methods were classified into four groups: enucleation after marsupialization, enucleation, resection with bone margin after marsupialization, and resection with bone margin. The potential risk factors were analyzed using exploratory factor analysis and Cox regression tests. 101 cases of ameloblastoma were reviewed, including 60 male patients and 41 female patients. A wide age range (11 to 84 years) and a median age at first visit of 36 were recorded, with most cases being mandibular tumors (93.1%). The recurrence rate was 23.8% (24 of 101 cases), and all recurrent cases received enucleation after marsupialization, or enucleation. Cox regression tests showed that recurrence was significantly associated with conservative treatment of teeth in contact with the tumor (hazard ratio = 2.45, 95% confidence interval = 1.06 − 5.67, p = 0.036). In addition, exploratory factor analysis showed that it is also important to obtain a definitive diagnosis by biopsy in order to prevent recurrence. The observation period for recurrent cases ranged from 3.7 months to 127.9 months (median 34.6 months), and 75% of recurrences developed within 5 years after enucleation. There were also cases of recurrence more than 10 years after enucleation, therefore long-term follow-up is recommended.

In addition to cancer-bearing status, chemotherapy is one of the moderate risk factors for the development of thromboembolism. However, there are few reports about it for oral cancer. Here, we report a case of pulmonary thromboembolism (PTE) that developed during chemotherapy for oral cancer. The patient was a 59-year-old man with left maxillary gingival cancer (T2N2bM0, Stage ⅣA). He complained of chest pain and dyspnea on the third day of the first course of TPF (docetaxel, cisplatin, 5-FU), which was performed as preoperative chemotherapy. Therefore, we performed an electrocardiogram and contrast-enhanced CT imaging. ST elevation, tachycardia and atrial fibrillation were observed on the electrocardiogram. PTE was also observed in his left lung in CT images. We immediately started the administration of β -blocker and anticoagulant therapies. After that the patient’s subjective symptoms disappeared and the electrocardiogram showed stability two days later. Therefore, chemotherapy was continued and completed. After three weeks, a left maxillary partial resection and left radical neck dissection were performed. Following the operation, there have been no PTE symptoms and he is making good progress.

The high perimandibular approach was developed for condyle fracture surgery. It has the advantages of easy access to the surgical field, low risk of facial nerve injury and non-visible surgical scars, making it superior when compared to other approaches (also used for intramasseter tumor removal). We recently performed the surgical removal of intramasseter hemangiomas in two patients using the high perimandibular approach. Both hemangiomas were located in the center of masseter muscle, and their diameters were approximately 1cm. The surgeries progressed smoothly, since we could secure a sufficient surgical field. The patients’ postoperative courses were uneventful, without complications such as facial nerve dysfunction and bad surgical scars. In conclusion, it was suggested that the high perimandibular approach is useful for the surgical removal of intramasseter tumors.