The use of heated tobacco products (HTPs) is rapidly increasing in Japan; however, few studies have investigated the reasons for their use. This cross-sectional study aimed to determine the reasons for HTP use, and was based on a web survey conducted in Japan involving 5,000 men and women, aged 20-69 years of age, in 2017. Participants with a history of using HTPs were included in this analysis (n=309). Ten categories of reasons for using HTPs were identified, and multiple responses were accepted. The explanatory variables were age and educational attainment, and the objective variable was each reason for HTP use. The prevalence ratio of each reason for HTP use, due to differences in age and educational attainment, was calculated using a Poisson regression model. The mean age of participants was 40.4 years (SD=12.8), and 29.5% of participants were women. Participants’ reasons for HTP use, in order of descending prevalence, were as follows: “because my friends use them” (137 people, 44.3%), “because I think they are less harmful than other cigarettes” (125 people, 40.5%), “because I prefer not to inconvenience others with cigarette smoke” (120 people, 38.8%), and “because I want to reduce the number of cigarettes I smoke” (104 people, 33.7%). As a result of Poisson regression analysis, young individuals answered “interested in flavor of HTPs” and “good design and function of HTPs” more frequently than older individuals, and those with high educational attainment were more likely to answer “because I use them when socializing with friends” than those with low educational attainment. It is therefore necessary to consider the regulation of tobacco advertising across tobacco products, including HTP, because of the potential impact of HTPs advertising.

 Few dentists are involved in meal planning at nursing homes with assisted living. Therefore, we believe that it is important to clarify the associations among meal type, oral environment, and physical status in residents of such facilities. The purpose of this study was to develop a simple screening method to assess the risk of dysphagia based on the physical status and oral environment. The subjects were 99 residents (mean age: 84.9±8.6 years) in two nursing homes offering assisted living. Their meal types, physical status, and oral environments were investigated. Data for analysis included three items (the Modified Water Swallowing Test, ability to brush independently, and stability of molar occlusion with consideration of denture wearing), along with data regarding meal types. These items were combined, and a chart to assess the risk of dysphagia in these residents was developed. When we classified the subjects into 8 categories by the data from the chart. Meal types in categories 1, 2, 3, 5 and 6 involved only regular or chopped food. On the other hand, blender food and parenteral intake were noted in categories 4, 7, and 8.

 The chart developed in this study assessed the risk of dysphagia based on the state of physical and oral environments in a simple manner using only the three above-mentioned items, and the discomfort to residents was minimal.

 Surface pre-reacted glass-ionomer (S-PRG) filler has the ability to release mineral ions, such as aluminum (Al³⁺), borate (BO₃^3-), fluoride (F^-), silicate (SiO₃^2-), sodium (Na⁺), and strontium (Sr²⁺). A three-way crossover trial using depth-specific analysis was conducted to estimate the enhancement of fluoride retention in oral biofilms when fluoride is applied at the same time as other mineral ions are released from experimental toothpaste containing S-PRG filler. Eighteen healthy participants wore in situ plaque-generating devices (a pair of 4-mm² enamel slabs) on their upper molars, and biofilm was allowed to form for three days. A slurry of toothpaste containing S-PRG filler (ϕ 3µm, 5wt%) was filtered. This filtrate contained Al³⁺ (340.5ppm), BO₃^3- (447.7ppm), Sr²⁺ (985.2 ppm), and F^- (181.0ppm). Devices were removed twice each day, immersed in the filtrate for one minute, and reinserted at the same location. Thirty minutes after the final immersion, devices were collected and samples were serially sectioned, with 2 x 2-µm sections taken first, followed by 4 x 4-µm sections for separation into outer, middle, and inner-layered fractions (300µm thick). This procedure was repeated until the required thickness was obtained. Samples treated with filtrates containing F^- and Sr²⁺ (PC) or F^- (NC) without S-PRG filler extract served as positive or negative controls, respectively. Fluoride and the three other mineral ions extracted from the thicker sections were quantified using a fluoride-selective electrode and ICP-atomic emission spectroscopy, respectively. The results were corrected for the biomass volume estimated by area measurement of stained 2-µm sections. Mineral concentrations among the layers within the biofilm samples were analyzed by the Friedman test, and comparisons of mineral concentrations among the three groups were evaluated by the Kruskal-Wallis test. Concentrations of Al³⁺ and BO₃^3- in the S-PRG group were significantly higher throughout the tissue than the PC and NC groups. Levels of Sr²⁺ in both the S-PRG and PC groups treated with solutions containing Sr²⁺ were significantly higher throughout the tissue than in the NC group. On the other hand, F^- concentrations in the S-PRG group were significantly higher throughout the tissue than in the NC group, and significantly higher in the outer and middle layers than in the PC group, although the experimental and two control biofilms were treated with filtrates containing the same level of fluoride. The results suggest that toothpaste containing S-PRG filler promotes the retention of fluoride in biofilms.

 There are several different forms of fluoridated dentifrices such as paste, gel, foam, and liquid types. Each type has applications that take advantage of various features.

 We evaluated the influence of differences in the form of 950-ppm F, NaF-containing dentifrices using the same volume (0.5g) and application method (toothbrushing with scrubbing method for 2 min, then mouth rinsing with 15 mL of distilled water for 5 seconds after spitting out) comparing paste, gel, and foam types on salivary fluoride levels 4 hours after toothbrushing. Eleven consenting healthy young adults participated in this study. Significant differences were noted in the fluoride ion concentrations in saliva after rinsing. The foam type showed the highest concentrations and maintained around 0.09-ppm F, which can inhibit demineralization and enhance re-mineralization, even 4 hours after rinsing. The area under the curve (AUC) of the ‘fluoride concentration - time’ for 240 minutes （AUC_0－240min）showed significant differences: the foam type including surfactants was the highest, whereas the gel type not including them was the lowest. Thus, the use of the foam type of dentifrice resulted in the retention of more fluoride in saliva.

 We suggest that the foam type includes not only surfactants but also a solubilizer as well as surfactant aids, which can enhance the rapid intraoral dispersion of dentifrices and release fluoride gradually from oral reservoirs such as the mucosa after adsorption or uptake.

 Child dental examinations have demonstrated that the development of caries is associated with obesity and mineral deficiency. However, few studies have addressed how the experience of caries in permanent adult teeth is associated with obesity and food allergy history. The objective of this study was to ascertain how the experience of caries is associated with obesity and food allergy history on the basis of medical examinations of new students at a dental university. The participants were 75 new students who entered the Faculty of Health Sciences of Osaka Dental University in 2018. Their height and weight were measured and used to calculate their body mass index. They completed a questionnaire on food allergy history and underwent a dental examination for caries by two dentists. While caries experience (≥1 tooth affected) was correlated with both obesity and milk allergy history, obesity and food allergy were not significantly correlated with each other. The present results suggest that the experience of caries is associated with obesity via the consumption of sweeteners and with milk allergy via mineral deficiency.