In neuropathy after surgical procedures such as wisdom tooth extraction and implantation of dental implants, not only hypoesthesia but also tingling and burning pain may occur in the area, which is called neuropathic pain.

　Diagnostic criterion for neuropathic pain is defined by the International Association for the Study of Pain (IASP) and the International Headache Society (IHS) according to lesions and diseases in the trigeminal nerve area.

　Regarding drug therapy of neuropathic pain, there are guidelines such as IASP and the Japan Pain Clinic Society (2016), and it is recommended to treat the oral area according to these guidelines.

　Many oral surgery-related facilities can treat according to these criterion and guidelines, and we consider that the role of secondary and tertiary medical institutions for neuropathic pain treatment in the oral region will be important.

Inferior alveolar nerve and lingual nerve injury is common in the field oral surgery. Nerve injuries are induced by extraction of impacted teeth, and implant impaction, and many cases require surgical nerve repair. Partial amputation injury case and the nerves complete amputation case are adaptation of the nerves surgical repair for severe nervous part equivalent to neurotmesis of the Seddon classification, but when nerves surgical repair is not performed immediately, traumatic neuroma can develop and cause neuropathic pain; accordingly, early diagnosis and treatment are important. The gold standard of nerve surgical repair was nerve end-to-end suturing, and autologous nerve graft. Nerve repair surgery can provide a reasonable result in improving sensation in the inferior alveolar and lingual nerve. More than 80% of patients experienced some improvement in sensation, and dysesthesia did not develop after surgery in any patient who did not have it before surgery.

　This article will be explained not only surgical therapy but also basic research on peripheral neuropathy to clinical practice.

We report the application of a temporary obturator as palliative care for a patient with full-thickness cheek defect arising from squamous cell carcinoma of the buccal mucosa.

　An 83-year-old man was diagnosed with squamous cell carcinoma of the left buccal mucosa. Resection of the tumor on the left buccal mucosa was performed in September 2012. Twelve months after the operation, metastasis in a left submandibular lymph node was found on magnetic resonance imaging and serial fluorine-18 fluorodeoxyglucose positron emission tomography / computed tomography. We carried out a radical neck dissection. However, recurrence was noted in December 2013. The patient and his family then requested to treat the carcinoma through supportive and palliative care. In April 2014, a full-thickness cheek defect, which occurred due to expansion of the tumor, resulted in pronunciation difficulties, eating disorder, bleeding, and a foul smell. Therefore, a temporary obturator was prepared using ethylene vinyl acetate copolymer (resin material), and placed on the fistula. Improvement in eating behavior and pronunciation, along with a reduction in malodor, were observed. Thus, the clinical application of a temporary obturator as palliative care was effective in improving the quality of life of the patient.

Trousseau syndrome is a clinical condition in which thromboembolism is caused by hypercoagulation associated with a malignant tumor. We report a case of cancer of the floor of the mouth with Trousseau syndrome. A 73-year-old man was referred to our hospital for cancer of the floor of the mouth. A blood examination revealed a high level of D-dimer (10.0μg/mL) and ultrasonography showed deep vein thrombosis. Magnetic resonance imaging (MRI) also revealed acute multiple cerebral infarction, and we made a diagnosis Trousseau syndrome. PET-CT showed FDG accumulation in the right floor of the mouth and the right submandibular lymph nodes, and in multiple bones. Based on the diagnosis of Trousseau syndrome, continuous intravenous administration of heparin was performed. At the end of the palliative irradiation for lumbar vertebrae, bleeding from the primary cancer occurred and heparin had to be discontinued. He was then transferred to the referring hospital for supportive care. He died from multiple organ failure about 2 months after first visiting our hospital.

Epstein-Barr virus (EBV) -positive mucocutaneous ulcer (EBVMCU) was first described as a lymphoproliferative disorder in 2010. It is recognized as a mature B-cell tumor in the 2017 WHO classification. EBVMCU results from iatrogenic or age-related immunosuppression and it appears clinically as a localized, well-demarcated ulcerative lesion at the cutaneous or mucosal sites. Histologically, EBVMCUs are characterized by the proliferation of EBV-positive atypical B-cells. In situ hybridization for EBV-encoded small RNA (EBER) reveals many positive cells. Most cases resolve with a reduction in immunosuppression, and some lesions spontaneously resolve. We report a case of EBVMCU that affected the maxillary gingiva. The patient was an 86-year-old woman with an ulcer in the palatal gingiva of the first molar region. At the initial consultation, a biopsy was performed, and we started administration of azithromycin (AZM) at 500 mg/day for 3 days because the left first molar had marginal periodontitis. Immunohistochemistry revealed positive reactions for CD20, CD30, and CD79a, and EBV-encoded small RNA (EBER) was found in many positive cells, which revealed EBVMCU. Because it was considered to have been caused by immune reduction due to aging, follow-up was selected as the treatment strategy. Basic periodontal treatment and oral cleaning instructions were provided in parallel with the follow-up observation. The patient had a spontaneous remission two months after the initial consultation. No recurrence was observed one year after the initial consultation．

Negative pressure wound therapy with instillation and dwelling (NPWTi-d), which can bring about automatic perfusion inside a wound, is becoming one of the standard treatment options for wound healing in all surgical fields. There are few reports regarding NPWTi-d in the field of oral and maxillofacial surgery. We report a case of post-operative infection of an iliac bone graft which was successfully treated with NPWTi-d. The patient was a 62-year-old man. We performed segmental resection of the mandible and modified radical neck dissection, followed by reconstruction with a plate and pectoralis major musculocutaneous flap for a lower gingival squamous cell carcinoma. One and a half years later, secondary reconstruction was performed using iliac bone. On the 13th day after surgery, an infection was found in the drain insertion site. After drainage NPWTi-d was commenced the following day and continued for 13 days. The abscess disappeared and the drainage wound was closed. However, on the same day a new abscess was found in the submandibular region anterior to the previous lesion and NPWTi-d was performed again for 15 days. Finally, the wound completely healed and the patient was discharged 48 days after surgery. Seven months after surgery, no infection has been observed in the grafted bone.