The purpose of this study was to investigate oral flora in independent persons aged over 80 years with more than 20 remaining teeth. The subjects were 22 participants of the 8020 campaign (6 males and 16 females) with a mean age of 81.3±1.6 years and an average of 24.7 teeth (Independent 8020 group). This group was compared with a group of 38 elderly people residing in nursing homes (10 males and 28 females) who had a mean age of 81.3±8.5 years and an average of 4.2 teeth (Nursing group with fewer teeth). Saliva samples were collected from the vestibular areas of the maxilla and mandible using cotton swabs. Cell numbers of microorganisms were expressed as colony forming units/ml (CFUs/ml) and compared between the two groups. The average number of Staphylococcus species was 65.2±74.4CFUs/ml in the Independent 8020 group and 400.3±352.1CFUs/ml in the group with fewer teeth (p<0.01); that of Candida albicans was 18.0±37.7 CFUs/ml in the Independent 8020 group and 152.9±211.9CFUs/ml in the Nursing group with fewer teeth (p<0.05). Both species showed statistically significant differences between the two groups. This suggests that the Independent 8020 achiever group had better oral hygiene and that the presence of many teeth may be associated with an increased awareness of dental health.

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The purpose of this study was to determine optimum diffusion parameters for diffusion weighted imaging (DWI) techniques, including echo planer imaging (EPI), single-shot fast spin echo (SSFSE), and steady-state free precession (SSFP) in Magnetic Resonance Imaging (MRI) of the Temporomandibular Joint (TMJ). A polyethylene tube with distilled water was individually positioned at the external acoustic meatus foramen in each of three volunteers with normal healthy TMJs. Images were obtained using three types of DWI at differing diffusion parameters, b-factors, and diffusion moment. Signal intensity and imaging ability for various anatomical structures, including the distilled water, were evaluated from each image. The details of the anatomical structures of the TMJ were unidentifiable in the images produced with EPI and SSFSE, but were identifiable on the SSFP images. A diffusion moment value from 100mT/m^*msec to 150mT/m^*msec for SSFP, in particular, restrained the signal intensity of the water, thereby protecting the comparably high image quality of the TMJ structure. In conclusion, only SSFP is capable of allowing interpretation of emerging pathologic conditions in the TMJ region, when used with a diffusion moment set at between from approximately 100mT/m^*msec to 150mT/m^*msec.

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This case report describes a 55-year-old woman with an amalgam-like metal remaining in alveolar bone after root-end sealing in 1964, and who then developed eczematous facial symptoms from 2000 onwards. Removal of the amalgam-like metal material improved the symptoms.

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Abnormalities in number of teeth are occasionally noted in clinical cases. Many theories have been proposed as regards the causes of the occurrence of supernumerary teeth, including atavism theory, mechanical tooth germ separation theory, tissue induction theory, and dental laminar morphological disturbance theory. However, none of these theories alone offers a sufficient explanation for this phenomenon. The incidence of supernumerary permanent teeth is approximately 1-3%. These are the maxillary anterior teeth, the maxillary molars, and the maxillo-mandibular premolars in terms of descending order of site of occurrence. On the other hand, incidence in the mandibular anterior tooth area, of which there have been few detailed reports, is about 0.01%, a markedly low value. In this paper, we report two rare cases of supernumerary teeth in the mandibular incisor area. We discuss their etiology and orthodontic treatment, and detail a differential diagnosis between the normal and supernumerary teeth. We found that it was difficult to establish a clear etiology and differentiation between the normal and supernumerary teeth.

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Surgical orthodontic treatment and dental implant therapy were performed on a man (aged 18 years 8 months) with mandibular prognathism and seven congenitally missing teeth: upper canines, first and second premolars and lower right second premolar. After 17 months of preoperative orthodontic treatment at age 20 years 1 month, sagittal split ramus osteotomy was performed using the remaining upper deciduous teeth as an anchor for intermaxillary fixation. In postoperative orthodontic treatment, the remaining deciduous teeth were extracted, and fixture installation was performed. The entire therapy required 4 years to complete (age 22 years 8 months). After completion of orthodontic treatment, superstructures were put in place. This patient had many dental problems, so multidisciplinary care was performed in conjunction with other departments to improve oral function and facial esthetics.

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