Temporomandibular joint dislocation occurs not only in the elderly but in all age groups. However, in recent years, the number of elderly people with various underlying diseases such as dementia, cerebral infarction, and Parkinson’s disease has increased, and the number of elderly people who suffer habitual dislocation of the temporomandibular joint has also increased. It is considered that there are potential patients in special nursing homes and health care facilities for the elderly, and thus a large-scale fact-finding survey is desired. There is a consensus that non-invasive therapy is the first choice for the treatment of habitual temporomandibular joint dislocation. Currently, non-invasive treatments as well as invasive treatments such as the mandibular condyle anterior motion inhibition method and the mandibular condyle reduction method are being performed at many facilities for treating habitual temporomandibular joint dislocation. It is our duty as surgeons to choose minimally invasive surgery as surgical therapy. Therefore, there is an urgent need to accumulate cases and determine trends through joint research with other institutions and to select minimally invasive surgery.

Kissing molars （KMs） are an extremely rare condition in which the occlusal surfaces of impacted molars contact each other, with roots pointing in opposite directions. KMs are classified according to the type of impacted molars, the contact style of the occlusal surface, and the presence or absence of a radiolucent area around the crown. We experienced two cases of Class Ⅱ true KMs without cystic variant. In these cases, second and third molars were impacted with occlusal surfaces facing each other, without a pericoronal radiolucency around the crowns. Case 1: A panoramic X-ray and computed tomography revealed complete impaction of the right mandibular second and third molars that had occlusal surfaces contacting each other. Both teeth were extracted under general anesthesia. Case 2: A panoramic X-ray and computed tomography revealed that the occlusal surfaces of the impacted left mandibular second and third molars were facing each other directly, and the root of this impacted second molar was close to the apical radiolucent lesion of the left mandibular first molar. Under general anesthesia, tooth extraction of the left mandibular first, second and third molars and periapical cystectomy of the left mandibular first molar were performed. The postoperative courses of both cases have been good.

This study aimed to evaluate the treatment outcome of osteonecrosis of the jaw （ONJ） in 18 patients receiving only denosumab. The patients comprised 11 males and seven females, with a median age of 82.5 years and mean age of 77.9 years. Fifteen patients were cancer patients with bone metastasis and three had osteoporosis. Stage 2 was the most common stage （77.8％）. Of the 18 patients, surgical treatment was performed in five patients, while purely conservative treatment was performed in 13. Surgical treatment achieved complete mucosal healing in 100％ （5/5） and was significantly correlated with treatment outcome on univariate analysis. In purely conservative treatment, two patients achieved complete mucosal healing and two patients achieved partial ONJ resolution. The treatment efficacy rate of conservative treatment was 30.8％ （4/13）. In four patients who were effectively treated by conservative treatment, their sequestrums detached spontaneously and epithelialized after a median of 12.5 months and mean of 15 months of discontinuing denosumab. ONJ progressed or was unchanged in five patients even after discontinuation of denosumab treatment. It may take a long time even if conservative treatment is successful. We recommend surgical treatment even for denosumab related osteonecrosis of the jaw when patients can tolerate surgery.

Intracranial abscesses caused by odontogenic infections rarely occur. Furthermore, brain abscesses rarely occur in the occipital lobe. We encountered a case of an occipital lobe brain abscess caused by an odontogenic infection. A 59-year-old man had a one-year history of chronic intermittent tooth pain, mainly in the right upper molar region. Two weeks after the last toothache subsided, he developed a severe headache. He consulted the neurosurgery department of our hospital. Because a malignant tumor of the occipital lobe was suspected based on an imaging evaluation, a craniotomy was performed. Pus was encountered intraoperatively, and a definitive diagnosis of a brain abscess was reached. Postoperatively, the patient consulted our department to determine whether the source of infection was derived from the oral area. Macroscopically, few obvious abnormalities were found in the oral area. Additionally, an accurate interview was difficult due to the influence of the craniotomy. Periodontitis was not confirmed until a jawbone imaging evaluation 10 days later. Oral anaerobic bacteria were thereafter confirmed in the pus specimen from the brain. Tooth extraction and oral care were performed in parallel with the antibacterial treatment administered for the neurosurgery. The brain abscess shrank and the patient’s postoperative condition was good.