We investigated three-dimensional decrease in the volume of the pulp chamber caused by age-related secondary dentin formation using micro-CT and evaluated the applicability of the results to evaluation of age taking into account sex, age and tooth type. Decrease was slightly higher in females than in males, and a higher correlation between decrease and aging was observed in females. A comparison between age-groups revealed that decrease progressed between the fifties and sixties in males, and the forties and fifties in females. A stronger correlation between aging and decrease was observed in the mandibular central incisors than in the mandibular second premolars. This correlation was higher than other correlations between sexes and age-groups.

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In this study, the corrosion resistance of Ag-Au-Cu-Pd system alloys consisting of 5 or 10 mass% indium was evaluated. Levels of element release and tarnish were determined and electrochemical measurements performed. Results were compared with those for commercial silver-palladium-gold alloy. In terms of electrochemical behavior, the transpassive potential of these experimental alloys was 168-248mV. Experimental alloys with 25 mass% Au showed similar corrosion resistance to control gold-silver-palladium alloy. Amount of released elements was 14-130μg/cm² at 7 days, which is in the allowable range for dental alloys. Addition of indium to Ag-Au-Cu-10mass%Pd system alloys was effective in increasing resistance to tarnish and alloys containing 10 mass% of indium showed a minimal decrease in L^* values after immersion. These findings indicate that 25Au-37.5Ag-15Cu-10Pd-2Zn-10In-0.5Ir alloy is applicable in dental practice.

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The purpose of this study was to investigate dental care utilization patterns in the elderly and to evaluate factors associated with regular dental check-ups in this age group. A total of 211 elderly people (50 men, 161 women) aged between 60 and 98 years were investigated. A cross-sectional survey by questionnaire was carried out on visitors to the Mihama Ikiiki Plaza (an institution for the elderly) in the city of Chiba, Japan between July and September, 2008. Items on the questionnaire included self-reported oral status, use of dentures, use of regular medication, oral problems, cleaning of teeth/dentures and dental care utilization patterns. The results showed that 135 (64.0%) of the responders had visited a dentist in the past year, 185 (87.7%) had visited the same dentist and 85 (40.3%) had had regular dental check-ups. A stepwise multiple logistic regression analysis adjusting for age and sex revealed that the factors associated with regular dental check-ups were significantly higher ADLs (odds ratio (OR)=0.439 in the partially insured and 0.192 in the fully insured in comparison with healthy subjects, p=0.0012), visiting the same dentist (OR=11.978 in comparison with not visiting the same dentist, p=0.0183) and cleaning teeth/dentures three or more times per day (OR=1.962 in comparison with cleaning them two or fewer times per day, p=0.0368). In this study, a higher ADL, visiting the same dentist and cleaning teeth/dentures three or more times per day were associated with having regular dental check-ups in the elderly. The best predictive factor for regular dental check-ups was a high ADL in the elderly.

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The purpose of this study was to determine the risk factors for root surface caries in the elderly and to evaluate the factors associated with gingival recession, one of the main risk factors for root surface caries. A total of 153 elderly people (35 men, 118 women) aged between 60 and 94 years (73.5±7.5 years) were surveyed. All participants were relatively healthy elderly who did not need special care in their daily lives. The survey was conducted in Chiba prefecture, Japan, and oral examinations and a questionnaire with face-to-face interviews were also carried out. Correlation analysis revealed that number of present teeth (p<0.001), gingival recession (p<0.001), bleeding on probing (p<0.001) and presence or absence of dentures (p<0.05) were significantly correlated with number of root surface caries. Stepwise multiple linear regression analysis for root surface caries revealed that the risk factors for increasing numbers of teeth with root surface caries were number of teeth with gingival recession (p<0.0001), bleeding on probing (p=0.0017) and self-reported dry mouth (p=0.0454). Sex (p<0.05), number of present teeth (p<0.001), bleeding on probing (p<0.01), the presence or absence of systemic disease (p<0.01), dentures (p<0.01), drinking alcohol (p<0.01) and smoking (p<0.01) were significantly correlated with amount of gingival recession by correlation analysis. Moreover, the risk factors for increasing number of teeth with gingival recession were living in an institution (p=0.0244), number of present teeth (p<0.0001) and smoking (p=0.0037), as determined by stepwise multiple linear regression analysis for gingival recession.

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Congenital fistulas of the lip are commonly found in the lower lip and accompany cleft lip. They are seen as a symptom of Van der Woude syndrome, which is predominantly hereditary. In contrast, congenital fistulas of the upper lip are rare. A number of hypotheses have been proposed to explain the pathogenesis of fistulas of the upper lip, including fusion failure of facial prominences and absence of mesoblasts, suggesting a relationship between this condition and the development of cleft lip. The pathogenesis of this disorder has been attracting attention. We report the case of a 5-year-old girl with congenital fistula of the upper lip.

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Intraoperative computer-assisted navigation has gained acceptance in maxillofacial surgery with applications in an increasing number of indications. We adapted a commercially available wireless passive marker system which allows calibration and tracking of virtually every instrument in maxillofacial surgery. Virtual computer-generated anatomical structures are displayed intraoperatively in a semi-immersive head-up display. Continuous observation of the operating field facilitated by computer assistance enables surgical navigation in accordance with the physician's preoperative plans. This case report documents the potential for augmented visualization concepts in surgical resection of tumors in the oral and maxillofacial region. We report a case of T3N2bM0 carcinoma of the maxillary gingival which was surgically resected with the assistance of the Stryker Navigation Cart System. This system was found to be useful in assisting preoperative planning and intraoperative monitoring.

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