The oral cavity, which various viruses and microorganisms can invade into, is a door to the digestive and respiratory tract. Therefore, the oral cavity is closely related to the development of many medical diseases. The oral symptoms of a systemic disease are wide-ranging and difficult to diagnose. However, we have to manage them by adequately gaining medical knowledge. In 2025, it is predicted that people over the age of 65 will make up more than 30% of the total population in the super-aging society of Japan. Therefore, we will give an outline of oral symptoms of the systemic diseases whose importance is expected to increase in the future.

In retransplantation, oral symptoms such as pain due to mucositis resulted in a disorder of mouth opening and communication. They might have enhanced the deterioration of one's systemic physical and mental condition. Furthermore, the patient's torment burdened the dental care staff technically and mentally. We are convinced through this case, that to accomplish difficult oral care, trustful relationships between patients and the other staff are needed. Such relationships are constructed by long-term involvement with humanity.

We report an extremely rare case of a granular cell tumor in the left side of the submandibular region. The patient was a 38-year-old woman who was referred to our clinic because of complaints about swelling in the left submandibular region. The lesion was elastic, hard, and mobile, and measured approximately 30mm in diameter during the first visit. No tenderness was present. We suspected that the lesion was a benign tumor. Through the use of an ultrasonogram, CT, and MRI, it is impossible to deny that a malignant tumor developed in the mandibular gland. The lesion was resected under general anesthesia. Histopathologically, it consisted of uniform cells that had eosinophilic granules in their cytoplasm. In immunohistochemistry, the granules of the cytoplasmshowed an immunoreaction to S-100 protein and neuron-specific enolase（NSE）. The positive rate of Ki-67 was less than 2%. There was no tissue from the submandibular gland, so a histopathological diagnosis of the granular cell tumor in the submandibular region was made. Post-operatively, there has been no evidence of recurrence for 2 years and 5 months.

We report a case of medication-related osteonecrosis of the jaw successfully treated with hyperbaric oxygen therapy（ HBO） and sequestrectomy. The patient was a 60-year-old male who was referred to our department for an examination of bone exposure of the left mandible. The patient's medical history revealed prostate cancer with multiple bone metastases, and the skeletalrelated events were treated by subcutaneous injection of 120 mg of denosumab per month for two years and eight months. Intraoral findings revealed alveolar bone exposure on the lingual side of the left mandible. The gingiva surrounding the exposed bone was erythematous with pus discharge. Conservative therapy with local irrigation was commenced; however, the area of exposed bone gradually increased. Eventually, the necrotic bone separated from the mandible began to mobilize, and sequestrectomy was then performed under local anesthesia. However, the gradual increase in the size of the exposed bone could not be controlled. Furthermore, phlegmon of the left cheek developed. Therefore, HBO was commenced, and 10 HBO sessions improved the left cheek swelling with an increase in the maximum mouth opening from 25 to 30 mm. Panoramic radiograph findings revealed that the necrotic bone separated from the mandible. After eight additional HBO sessions, sequestrectomy was performed under general anesthesia. As a result, the wound in the mandible healed completely with epithelialization in two months. Two years and 6 months after the operation, no relapse of mandibular osteomyelitis was observed. In addition, further bone metastasis from the prostate cancer had been controlled by oral administration of an anti-androgenic hormone.