The effects of change in occlusal pressure on the cortical mechanisms responsible for hearing were investigated. Changes in the magnetic field in response to auditory stimulation when subjects (5 healthy, right-handed, male volunteers aged between 22 and 30 years) bit a cotton roll were analyzed by using magnetoencephalography. All equivalent current dipoles estimated from the fields obtained under 3 different bite force conditions were closely localized within 1 mm of those obtained in the non-bite control group. No significant difference was observed between the bite and non-bite conditions in the latency of the 100-ms component (N100 m) of the magnetic fields. The amplitude of the N100 m component decreased with increase in bite pressure in both the right and left hemispheres (p<0.05). These results suggest that an increase in bite pressure influences auditory function.

Kaposi's sarcoma (KS) is one of the most common diseases in patients with acquired immunodeficiency syndrome, but is rarely encountered in dental practice in Japan. We encountered a case of oral KS (OKS) presenting in the hard palate, gingiva, and tongue in a 41-year-old man. We report the results of imaging, including computed tomography (CT), magnetic resonance imaging, and positron emission tomography/CT in this case. The process leading to an imaging diagnosis of OKS is discussed, emphasizing the importance of collating clinical, laboratory, pathological, and radiological findings. The present results suggest that mapping of accurate tumors is very important in cases of OKS, and that multiple or bilateral manifestations, ill-defined margins, osteolysis, and swollen lymph nodes, in particular, need to be taken into account.

We report a case of gingival recession in the mandibular incisor region requiring a connective tissue graft. The patient was a 17-year-old girl who visited the Tokyo Dental College Chiba Hospital in 2014 with the chief complaint of gingival recession in the lower incisor region. She had received orthodontic treatment for 5 years and noticed the gingival recession on completion of active orthodontic treatment in 2013. Gingival recession in tooth #31 extended 3 mm beyond the muco-gingival junction (MGJ) and was clinically diagnosed as Miller Class II recession; probing depth was 6 mm. Following initial periodontal therapy, a connective tissue graft procedure was implemented. The connective tissue was harvested from the left palate. Healing was uneventful, and the grafted site showed a favorable outcome at 6 months postoperatively. We are continuing to carefully monitor the condition of periodontal tissue.

We report a case of an elderly patient with chronic periodontitis requiring periodontal surgery. An 86-year-old man presented to Tokyo Dental College Suidobashi Hospital with the chief complaint of tooth fracture in the anterior region and occlusal pain in the posterior region. Clinical examination revealed 47% of sites with a probing depth (PD) of ≥4 mm and 47% of sites with bleeding on probing. Radiographic examination revealed generalized moderate horizontal bone loss with localized vertical defects. A clinical diagnosis of moderate chronic periodontitis was made. The patient's oral health-related quality of life (QoL) was also assessed at the time of each periodontal assessment. Initial periodontal therapy was provided followed by periodontal surgery. Open flap debridement was performed at sites with a PD of ≥5 mm (teeth #15–17). Surgical crown lengthening with an apically positioned flap was performed on #11 and 13 to gain an adequate biological width for the subsequent crown restoration. After confirming the stability of the periodontal tissue, provisional restorations were replaced with final restorations. No further deterioration was observed in the periodontal condition during the subsequent 1-year period of supportive periodontal therapy. Oral health-related QoL was markedly improved by the periodontal therapy. This suggests that periodontal therapy plays an important role in improving and maintaining oral health-related QoL in elderly people.

Odontogenic keratocysts and central giant cell granulomas are distinct entities of separate origin that may appear simultaneously in the jaw, making them difficult to differentiate. The objectives of this paper are to report a case of a 54-year-old man presenting with a large lesion in the right mandible and to describe the histological characteristics of that lesion. Imaging revealed tumefaction and multilobulation. The case was surgically managed. Histopathological examination revealed that the lesion was a hybrid of an odontogenic keratocyst and a central giant cell granuloma. It remains unclear as to whether this lesion represented a coincidental or related injury. Since both types of lesion involved have a high rate of recurrence, however, long-term follow-up is scheduled.

We report a case of severe chronic periodontitis treated and longitudinally maintained by a periodontist and dental hygienists. The patient was a 45-year-old woman who presented with the chief complaint of gingival bleeding and tooth mobility. An initial examination revealed generalized gingival inflammation and subgingival calculus in the premolar and molar regions. Premature contact was observed in #14 and 45. Clinical examination revealed 42% of sites with a probing depth (PD) of ≥4 mm and 44% of sites with bleeding on probing. Radiographic examination revealed vertical bone resorption in #35, 36, and 45, and horizontal bone resorption in other regions. Based on a clinical diagnosis of severe chronic periodontitis, initial periodontal therapy consisting of plaque control, scaling and root planing, and removal of an ill-fitting prosthesis was performed. Following suppression of inflammation, occlusal adjustment of premature contact sites was performed. Open flap debridement was performed for teeth with a PD of ≥5 mm. After confirming the stability of the periodontal tissue, final prostheses were placed on #16, 35–37, and 46. Following re-evaluation, the patient was placed on supportive periodontal therapy. It has been 11 years since the patient's first visit, and the periodontal conditions have remained stable. Meticulous periodontal care maintained over a number of years by a periodontist and dental hygienist have yielded a clinically favorable outcome.

Conversion disorder is a condition in which psychological stress in response to difficult situations manifests as physical symptoms. Here, we report a case of postoperative coma due to conversion disorder in an elderly oral cancer patient. An 82-year-old woman was referred to Tokyo Dental College Chiba Hospital with a mass lesion on the tongue. A biopsy revealed a well-differentiated squamous cell carcinoma. Surgical treatment was performed for the tongue carcinoma and tracheotomy for management of the airway. On postoperative day 5, the patient exhibited loss of consciousness (Glasgow Coma Scale: E1, VT, M1; Japan Coma Scale: III-300). The patient's vital signs were all normal, as were the results of a full blood count, brain-CT, MRI, and MRA. Only the arm dropping test was positive. Therefore, the cause of the coma was diagnosed as conversion disorder. Seven hours later, the patient showed a complete recovery.

The aim of this study was to identify factors in the working environment associated with regular dental attendance. Thirty-three general practitioners provided data on 488 patients who underwent dental maintenance between 2003 and 2015. The age of the patients ranged from 40 to 65 years. Appointment adherence, employment format, overtime work, night work, and subjective evaluation of work were investigated. Multiple logistic regression analysis was performed to identify factors associated with regular dental attendance. Among all participants, 296 (60.7%) were female, 320 (65.6%) worked full-time, 193 (39.5%) worked overtime, and 34 (7.0%) worked nights. The results of the analysis revealed that only night work was a significant factor after adjusting for sex, age, and employment format (odds ratio, 0.220; 95% confidence interval, 0.088–0.550). The results of this study suggest that night work disturbs regular dental attendance.