The purpose of this in vitro study was to evaluate the tooth remineralization process in relation to different topical fluoride applications with QLF. Eighty bovine enamel specimens were mounted on acrylic rods and polished. Incipient lesions were formed in specimens by immersion for 48 and 96h in a demineralizing solution. The lesions were quantified with parameter ΔQ (total mineral loss from the lesions). Then, specimens in each group were divided into 4 subgroups receiving different fluoride treatments (control, fluoridated dentifrice, APF-gel, and fluoridated dentifrice plus APF-gel). All specimens were immersed in artificial saliva for 28 days, excluding the duration of the respective fluoride treatments. In the low demineralization group, mineral recovery reached a plateau after 9 days. For groups with high demineralization rates, such a plateau was reached after 15 days. For each demineralization period, the rate of recovery of control and F-dentifrice groups was higher than for both APF-gel treated groups (p<0.05). There was no difference between the mineral recovery rates of the two APF-treated groups. It was concluded that APF-gels inhibited mineral recovery in comparison with F-dentifrice treatments or artificial saliva alone.

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The purpose of the present study was to identify factors related to oral health care among inpatients with neurological disorders. For each of the 143 inpatients included in our study, the oral as well as general health (level of consciousness, feeding style, etc.) conditions were investigated using an assessment sheet at their first visit. The study revealed that 80% of the hospitalized patients showed "dysfunction of oral periphery muscle and/or tongue movement", 60% of them presented "dry mouth" and/or a "reduced level of consciousness", and 25% exhibited "constant open mouth with no intention". By logistic regression analysis of the data, it was strongly suggested that "severe debris accumulation" could be attributed to "dry mouth". Furthermore, "dry mouth" was found to be significantly correlated with several features, including "constant open mouth", "impaired mouth rinse", "dysfunction of oral periphery muscle and/or tongue movement", and "reduced level of consciousness", which are conditions often observed in patients with neurological disorders. These results suggest that inpatients with both a "reduced level of consciousness" and "constant open mouth" should receive professional oral care in order to prevent "dry mouth", and undergo a careful follow-up to promote the maintenance of good oral hygiene and functions.

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This study was conducted to examine the effects of the October 2004 Niigata Chuetsu Earthquake on the oral health status of elementary school and junior high school children. The results of dental examinations performed annually at schools in the four hardest hit districts (N, O, T, and U) were compared between before and after the quake with respect to the prevalence of dental caries, expressed by DMF index rates, rates of filled teeth, and DMFT. The findings were as follows: 1. In the quake-stricken communities, the filled tooth ratio DMF value calculated in 2005 had decreased notably compared to the figures in 2003 and 2004. Significant differences were noted between pre- and post-quake examination data for students in 10 grades including sixth-year students of elementary school (p<0.01) excluding District T and second-year students of junior high (p<0.01) excluding District U. For all the indicators of caries prevalence, significant changes were observed in fourth-year pupils and four other grades in every district. 2. The ratio of the number of decayed teeth treated in the four districts combined to the total in Niigata Prefecture dropped significantly in third graders (p<0.05) at elementary school and pupils in two other grades. 3. The DMFT incidence in the four districts increased notably among junior high school students in the aftermath of the quake. The ratio of the number of DMF teeth in the four districts combined to the total figure of the entire prefecture significantly increased in the post-shock years, particularly among students in two grades of junior high school (p<0.01). 4. There was no distinct change in the DMFT ratio before and after the earthquake, although the ratio showed a tendency to increase after the quake among junior high school students. All these findings suggested that the earthquake caused a decrease in the ratio of decayed tooth filled in the affected districts. Therefore, we concluded that when measures to deal with a natural disaster are discussed from the viewpoint of dental health services, it is necessary to take into account the effects on school dental health.

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We performed an in vitro study using quantitative light-induced fluorescence (QLF) to evaluate enamel remineralization caused by the application of fluoride toothpaste. Artificial incipient carious lesions were formed in bovine dental enamel by immersion for 48 or 96 hours in a demineralizing solution. Each demineralization group was then divided into four subgroups based on the four different concentrations (0, 500, 1,000, and 4,000ppm) of fluoride toothpaste applied. The remineralization of carious lesions was calculated at 28 days using data obtained with QLF. Regarding the 48-hour demineralized group, remineralization in the 0, 500, and 1,000ppm fluoride dentifrice subgroups showed an approximately 95% recovery at 28 days. However, the 4,000ppm fluoride dentifrice subgroup showed only a 40% recovery rate. Regarding the 96-hour demineralized group, remineralization in the 0 and 4,000ppm fluoride dentifrice subgroups was lower than in the other two subgroups. We concluded from this in vitro study that dentifrice containing high concentrations of fluoride inhibited remineralization in carious lesions.

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Objective: The purpose of this study was to analyze the relationship between socioeconomic factors and four types of dental health behavior: intake of sugary foods or drinks, daily tooth brushing habit (DTB), daily use of fluoride toothpaste (FTP), and regular dental check-ups (RDC-up). Materials and methods: Nine hundred and forty-nine 12-year-old school children in 21 schools were randomly selected in the Western Province (the most urbanized province) of Sri Lanka (WPS). The ten independent variables for the multiple logistic regression analyses (MLRAs) were as follows: gender, council, ethnic group, parents' educational background (PEB), parents' occupation, household income, number of siblings, sources of dental information, regular dental check-ups, and six factors of community development (abbreviations: Fa-LCD1-6) based on a factor analysis of 24 household appliances and other development indicators. MLRAs were performed with the four dental health behaviors as dependent variables, and the differences among the behaviors were compared. Results: Combinations with odds ratios above 2.0 were: Tamil group vs. intake of sugary foods (exp (-B)=5.44), Sinhalese vs. FTP (2.34), TV info source vs. FTP (2.32), Fa-LCD1 vs. addition of sugar between meal (2.16), Fa-LCD1 vs. sugared tea (2.16), and Sinhalese vs. RDC-up (2.11). Six combinations had significance levels of p<0.001: gender vs. DTB, Fa-LCD1 vs. (addition of sugar between meals, sugared tea, and FTP), RDC-up vs. (addition of sugar and DTB). Extensive factors widely influencing more than two of the four behaviors were: ethnic groups, PEB, Fa-LCD1, and RDC-up. Conclusions: Important factors which should be considered in dental schemes, campaigns, or activities are: gender, ethnic groups, PEB, Fa-LCD1, and RDC-up.

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Objective: The purpose of this study was to analyze the significance of dental health behavioral and socioeconomic factors influencing the DMFT of 12-year-old school children in the Western Province of Sri Lanka (WPS), a highly urbanized region with marked socioeconomic diversity. Materials and methods: The data set comprised 949 12-year-old school children in WPS. The independent variables for the multiple logistic regression analyses (MLRAs) included four dental health behaviors (4-DHBs) (sugar consumption habits, tooth brushing habits, fluoride toothpaste use, and regular dental check-ups), as well as 10 socioeconomic factors. Final models and odds ratios for each variable were obtained by backward-MLRAs. Results: The distribution of the DMFT showed an exponential dropping pattern. Differences in the DMFT between genders and among three ethnic groups were not significant. Fluoride toothpaste use was the main behavioral factor related to a low DMFT of 12-year-old children, especially among Sinhalese children in WPS. The most significant socioeconomic factor was ethnic group. Conclusions: Fluoride toothpaste was the most powerful behavioral factor related to the low DMFT of 12-year-old children, especially for Sinhalese children in WPS. On the other hand, the most significant socioeconomic factor was ethnic group. Dental health behaviors were affected by traditional and religious customs and habits, which seem to sometimes exhibit additive effects, but occasionally have offsetting effects, on dental caries. It is necessary to monitor the important cariogenic and relevant socioeconomic factors, although the level of caries prevalence in this province was demonstrated to be very low.

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The disaccharide trehalose inhibits bone loss in ovariectomized mice. In the present study, we examined whether the preventive administration of trehalose inhibits the reduction of the bone mineral density (BMD) after menopause using ovariectomized rats, an animal model of human postmenopausal osteoporosis. Female Sprague-Dawley rats were randomly allocated into four groups: a Sham group, an OVX group, a preventive administered with trehalose group (Pre-TH), and an administered with trehalose group (TH). The rats of OVX, Pre-TH, and TH groups were ovariectomized and the Sham group was sham-operated at 8 weeks of age, and given trehalose (10mg/kg) or sterile distilled water by oral administration daily for 12 weeks (4 to 16 weeks of age), and the influences on the weights of the body and womb, and the BMD of the femur and lumbar vertebra were examined. There was no significant difference between the OVX and Pre-TH or TH groups regarding body and womb weights. In contrast, the BMD of the femur and lumbar increased significantly in the Pre-TH compared with the OVX group. These findings suggest that the preventive administration of trehalose may effectively inhibit osteoporosis after menopause.

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In order to test whether the occlusal contact pattern is a factor that contributes to the development of non-carious cervical lesions (NCCLs), 15 dentists clinically investigated their prevalence in the general population in two different ways to classify the occlusal scheme (one based on the tooth-contact pattern during wakefulness and the other on that during sleep). We established the occlusal contact pattern of 240 subjects during sleep bruxism with BruxChecker. We checked the 6,564 teeth of the total subjects and examined the NCCL prevalence regarding each tooth. The overall prevalence of NCCL was 11.4%. The prevalence increased with age: 7.1% for people in their 20s to 15.8% for people in their 50s. Based on the standard 5-category occlusal contact patterns established by BruxChecker, there was a significant difference between the proportion of NCCLs identified in bilateral group function grinding subjects (12.8%) and that in bilateral canine dominance grinding subjects (3.6%). Using the new 3-category system (incisor-canine grinding (IC) subjects, incisor-canine-premolar grinding (ICP) subjects, and incisor-canine-premolar-molar grinding (ICPM) subjects), there was a significant difference between the proportion of NCCLs identified in bilateral ICP subjects (13.5%) and bilateral ICPM subjects (13.6%) than in bilateral IC subjects (3.6%). It was proportional to the laterotrusive-side occlusal contact area. We conclude that the prevalence of cervical lesions is significantly related to occlusion, and that the risk of non-carious cervical lesions is a function of the laterotrusive-side occlusal contact area.

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