Burning tongue syndrome is a collective name for diseases that cause a burning pain of the tongue, however, no clear clinical or laboratory abnormalities may be observed. The pain is a superficial, described as a burning sensation, and may occur in the tongue, palate, lips, buccal mucosa, gingiva, and teeth. Seventy-five percent of patients with burning tongue syndrome are middle aged women in their 50's and they are often post-menopausal. However, this syndrome may be observed in all ages regardless of gender. A variety of pathological causes have been proposed for this mysterious syndrome.
Pain can be classified as nociceptive, neuropathic, or psychogenic, and the mechanism for the onset of burning tongue syndrome has been investigated in relation to all of these. Pain can be classified as acute or chronic. While acute pain may be alleviated with rest or analgesics, chronic pain lasts beyond a reasonable time needed for healing of an acute disease or wound and it may overlap with psychogenic pain. Many cases of burning tongue syndrome have been classified as chronic pain (psychogenic pain).
Marked inflammation or tissue damage in burning tongue syndrome that are sufficient to account for the pain have not been detected. However, mild glossitis, micro-trauma caused by dentures, and dry mouth are often observed. Therefore, burning tongue syndrome may result from chronic pain caused by chronic irritation to the nociceptor in these minor lesions. In recent years, burning tongue syndrome has been proposed to be a neuropathic pain of the lingual nerve involving a taste disorder.
Since the causes and background factors of burning tongue syndrome are not obvious, multiple treatments exist. The cases with dry mouth are treated with oral drugs such as pilocarpine hydrochloride, to promote salivation. For cases with taste disorder, zinc therapy using polaprezinc has been effective. For cases with suspected non-organic pain, anti-anxiety drugs or anti-epileptics, such as benzodiazepine, are recommended. The anti-epileptics, Rivotril^® and Landsen^®, enhance the GABA neuron activity specifically and are considered to be effective for neuropathic pain in burning tongue syndrome. For cases with masked depression, tetracyclic antidepressants or SSRIs are recommended. Patients with masked depression may have physical complaints and autonomous neurological symptoms, while the symptoms of depression are inconspicuous. Therefore, they have some common characteristics with patients with burning tongue syndrome.

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Airway narrowing caused by endotracheal stenosis or glottis dilatation disorder is comparatively rare and a few cases present with the sleep apnea syndrome. We performed a 3-point airway pressure examination to evaluate the occlusion site and the strength of the breathing effort in three cases of the obstructive sleep apnea syndrome undergoing nocturnal polysommnography. All three cases showed strong breathing effort, however, the site of airway narrowing differed among the cases. We treated 2 of the three cases successfully by CPAP. It was thought that to elucidate the clinical condition of the three cases diagnostic evaluation should include airway pressure measurement to assess the site of functional airway narrowing, and laryngoscopy and imaging to determine the anatomic site of stenosis.

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An abnormal tooth whose crown develops in the opposite direction is called an inverted tooth.
We report the case of a 62-year-old female patient who was detected to have an inverted tooth in the left nasal cavity. We extracted the tooth easily from the nasal cavity under general anesthesia. Pathologic examination revealed the tooth to be a supernumerary canine caused by an ectopic supernumerary dental organ. Most inverted teeth are caused by ectopic dental organs, while other causes include the remains of deciduous teeth, and damage and the displacement of the maxilla. At the beginning of the development of the palate, the sutures between the incisors and canines are not yet completely closed. When the suture is separated, the adjacent dental organ can be easily displaced; therefore, most ectopic teeth are incisors or canines. Furthermore, since closure of the suture on the left side is delayed as compared with that of the rightside, ectopic teeth are twice as common on the left side as on the right side. Some inverted teeth may never be diagnosed if they cause no symptoms. We recommend extraction of an inverted tooth as soon as it is detected, in order to prevent repeated attacks of sinusitis and formation of a cyst of the dental sac.

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Surgery is the treatment of first choice for parotid gland tumors. However, since the facial nerve runs through the face, the surgery entails the risk of development of facial paralysis. Therefore, the patients sometimes hesitate to undergo surgery. The histopathology of the tumors is also multifarious, and making a diagnosis preoperatively is difficult in many cases. This is a report of our study of the clinical characteristics, including the age, sex, histopathology, duration of illness, tumor size, tumor localization, postoperative complications, pleomorphic adenoma found in many cases and Warthin's tumor in 84 patients who were treated at our department during the past five years from April, 2002 to March 2007.

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Neurinoma is a benign peripheral nerve tumor that arises from the Schwann cells. It may occur anywhere in the body, but predominantly arises in the head and neck region as compared with other regions of the body.
In Japan, numerous cases of glossal neurinoma in the oral cavity have been reported, however, glossal neurinoma outside the oral cavity is rare. We encountered one case of neurinoma of the glossal nerve in the neck region, outside the oral cavity.
Case report: A 16-year-old female presented to our hospital with the chief complaint of submaxillary swelling on the right side. Preoperative CT, ultrasonography and aspiration cytology failed to reveal the diagnosis. The patient was diagnosed as having a benign neurinoma by intraoperative rapid pathologic diagnosis. Extirpation beneath the tunica was perfomed under a microscope in order to keep the nerve intact. The patient was aware of numbness and a feeling of swelling of the tongue on the right side postoperatively, but these symptoms improved in about two weeks, and the patient showed a satisfactory postoperative course.

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Recently, genes related to hearing acuity have been identified from the mutations of various hearing-impaired model mice. In the article, we tried to determine the locus of a gene which was also responsive to our originally established hearing-impaired model mouse. The model mouse was originated from closed-colony ICR. Linkage analysis was used for the method. We cross-backed the mouse to Mus. m. castaneus (CAST), of which microsatellite markers were understood and determined the gene location by comparison of length of microsatellite markers after amplification by polymerase chain reactions (PCR). Individuals with hearing impairment were confirmed by auditory brain stem response (ABR) and length of PCR products was measured by electrophoresis. The results suggested that the impairment was caused by single gene abnormality and mutation existed in the 11^th chromosome.

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[in Japanese]

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