This paper outlines the revision process and contents of the revised ‟ Pathogenesis and Management of Drug-Related Osteonecrosis of the Jaw: Osteonecrosis of the Jaw Study Committee Position Paper 2023, ” especially concerning the prophylactic withdrawal of ARA for tooth extractions and the treatment and management of MRONJ.

　A systematic review was conducted on the prophylactic withdrawal of ARA at the time of tooth extraction. With the results, the position paper proposes that, ‟ in principle, ARA should not be withdrawn at the time of tooth extraction”. Regarding MRONJ treatment, surgical treatment has a higher cure rate than conservative treatment in stages 2 and 3, and surgical treatment is prioritized if the general condition allows. While, in stage 1, both conservative and surgical treatment are acceptable.

　We hope that you will read Position Paper 2023 carefully, disseminate its correct content, and reflect it in the health of the public.

Since hip and vertebral fractures cause deterioration of quality of life and life expectancy, we call them ‟ Bone Attack , ” and awareness of the importance of osteoporosis treatment is being promoted. In Japan, the diagnostic criteria for osteoporosis consist of bone mineral density and a history of fragility fractures. To prevent Bone Attack, it is necessary to increase the screening uptake rate for primary fracture prevention and to implement secondary fracture prevention. Osteoporosis drugs are used according to fracture risk among six drugs with evidence of fracture-preventing effects.

NF1 is characterized by café-au-lait spots and neurofibromas and occurs in about 1 in 3000 people. This disease is often associated with various lesions, and it is necessary to evaluate the risk factors for surgery. In this report, we describe a case of NF1 treated with orthognathic surgery. The patient, a 42-year-old male, had been aware of facial asymmetry and malocclusion since his twenties and was referred to Tohoku University Hospital. His facial appearance was skeletal class Ⅲ , concave, and the chin was deviated to the right. He had right temporomandibular joint noise, with an opening of 54mm. CT showed that the right mandibular branch was buccolingually narrow and a diffuse neurofibroma was close to the posterior border of the right mandible. Difficulties associated with surgery included the narrow width of the mandibular branch, which makes splitting difficult if a sagittal splitting ramus osteotomy (SSRO) is chosen, and the possibility of vascular collapse and the formation of an arteriovenous aneurysm due to his medical history, so IVRO was chosen. He was operated on under general anesthesia and progressed well without postoperative bleeding. He was discharged 14 days after the surgery and has been stable for four years.

In Japan, total temporomandibular joint (TMJ) replacement for progressive condylar resorption (PCR) has been covered by insurance since April 2020, following approval for use in 2019. As a result, total TMJ replacement is becoming a standard treatment for diseases with condylar defects. We report a case of bilateral PCR treated with total TMJ replacement. The patient was a 35-year-old female. She was referred to our department in September 2017 with the chief complaint of trismus. She was treated according to a diagnosis of temporomandibular disorder, but when she was re-examined, PCR and open bite were found, and total TMJ replacement was performed under general anesthesia in November 2021. One year after surgery, the patient is doing well and the occlusion is stable without any adverse events such as infection or neuropathy.

Dermoid cyst is a cystic lesion mainly caused by migration of ectodermal tissue during the embryonic period and is most commonly observed at the midline of the oral floor. The contents of the cysts are well known to show a callus-like appearance composed of keratides and other tissue from subcutaneous organs, but this lesion often has serous or fatty fluid. Therefore, DC is difficult to diagnose on imaging alone because of various images on MRI. Enucleation is the first-line treatment for this disease, and marsupialization is not common. We report a case of a sublingual dermoid cyst which was successfully treated by marsupialization. The patient was a 53-year-old woman. She was referred to our hospital with the complaint of a mass on the oral floor. Contrast-enhanced CT showed a 24 × 23 × 22 mm spherical hypo-absorbable area extending from the midline of the floor of the mouth to above the hyoid muscle, and MRI showed a high signal on T1-weighted and a slightly low signal on STIR images, indicating lipoma. However, during biopsy we confirmed that it was a cystic lesion and temporal marsupialization was performed. The histopathological diagnosis was dermoid cyst, and excision was planned. However, the lesion shrank remarkably and the submucosal remnant tissue was excised four months after biopsy, and there were no histopathological findings indicating a dermoid cyst.