In this study, the effects of: 1) fluoride addition during remineralization, and 2) pH-cycling time of demineralization and remineralization on the nanoscale surface properties of enamel, were investigated by measuring micro-surface roughness and the amount of demineralization.

 Human enamel samples were cut and polished. The specimens were randomly divided into 4 groups of 12 specimens each and subjected to 4 experiments. Two other specimens were used for morphological observation.

 In Experiment 1, the specimens were immersed 4 times in both demineralization and remineralization solutions for 5 minutes each. In Experiment 2, the specimens were immersed 4 times in both demineralization and fluoride remineralization solutions for 5 minutes each. In Experiment 3, the specimens were immersed 20 times in both demineralization and remineralization solutions for 1 minute each. Finally, in Experiment 4, the specimens were immersed 20 times in both demineralization and fluoride remineralization solutions for 1 minute each. After being immersed in these solutions, micro-surface roughness (arithmetic mean roughness (Ra) and root mean square roughness (Rq)) and amount of demineralization were measured. Two-way ANOVA was used to analyze Ra, Rq averages, and the amount of demineralization with pH-cycling time and fluoride addition to the remineralization solution as the two factors. The microstructure of the samples was observed with an atomic force microscope (AFM) images.

 Both Ra and Rq were significantly lower with fluoride addition (p < 0.05), but there was no significant difference with the pH-cycling time. The amount of demineralization showed no significant difference with both factors. In the AFM image, a larger crystal size was observed in the case of fluoride addition.

 When the enamel surface properties were evaluated on a nanoscale, the results indicated that micro-surface roughness of enamel was reduced significantly with the addition of fluoride during remineralization but not by the size of the crystals． Furthermore, it was suggested that micro-surface roughness was related to the total pH cycling time.

 Diabetes and periodontal disease have common risk factors of being overweight and smoking, while diabetes and dental caries both benefit from common dietary guidance including sugar control. Therefore, health behaviors associated with both diabetes and oral disease could be targeted by a common risk factor approach. The aims of this study were to clarify the association between eating habits and oral health behavior in patients with type 2 diabetes, and elucidate the priority issues with a common risk factor approach. We administered a questionnaire about eating habits and oral health, performed salivary multi-tests and oral examinations, and then analyzed the relationships between each item. Significant correlations were found between [Sloppy eating] or [Sweet snack] and the acidity of saliva. [Sloppy eating] was also associated with the [Symptom of hypersensitivity]. [Bleeding gums on brushing] and [Toothbrushing before bedtime] were associated with blood or protein in saliva. Blood in saliva was also associated with [Chewing firmly with molars]. Binomial logistic regression analysis using [Blood in saliva: High level] as the outcome variable revealed that a high level of blood in saliva was significantly correlated with [Toothbrushing in the workplace/outside] and [Toothbrushing before bedtime]. Our findings suggest that strengthening dietary guidance to focus on the habit of eating snacks, and oral health guidance to acquire favorable tooth brushing habits might lead to improvement in the oral environment of diabetic patients.

 The use of heated tobacco products has rapidly increased in Japan. Here, we tested an oral health-based intervention as a tool to mitigate tobacco usage. A one-day smoking cessation program that emphasized oral health was offered to members of a common occupational sector in 2019. We analyzed data from 241 male smokers (20-54 years old; mean 33.2±10.5 years). The main outcome was change in the desire to stop smoking. Survey items included the level of tobacco use, smoking history, desire to quit smoking, halitosis, lung age, respiratory function, carbon monoxide (CO) concentration in exhaled breath (blood carboxyhemoglobin concentration), and smoking type. The total number of heated tobacco users was 72 (29.9%), which included those who used tobacco in conventional with conventional smoking. Overall, the intervention caused a significant increase in the desire to quit smoking (25.7% before to 44.4% after intervention, p<0.05). The increase was significant for both younger (< 40 years old) and older (> 40 years old) populations (28.6 to 49.7% and 8.7 to 34.8%, respectively, p<0.05). Younger individuals were more likely to report a desire to quit smoking. No significant change was observed for participants who used conventional smokins. The exhaled CO concentration in heated tobacco users was lower than that in conventional smokers (p<0.001). However, halitosis, the lung age difference, and respiratory function did not differ between the two groups (p>0.05). Our findings indicate that oral health-focused intervention may be effective for increasing smoking cessation in heated tobacco users as well as other smokers.

 This study aimed to develop a questionnaire for the gingivitis prevention program for junior high school students and its evaluation method and examine factors associated with gingivitis using the PRECEDE-PROCEED model. A questionnaire survey and oral examination were conducted involving 118 second-year students (66 males and 52 females) at a secondary school in Kawasaki City, Kanagawa Prefecture. The PMA-index (Schour & Massler) was used to investigate the status of gingivitis. The question items were based on the questions in the Comprehensive Diagnostic Programme for Periodontal Diseases in Adults (FSPD34 type), whose basic structure was the PRECEDE-PROCEED model as a reference, and question items considered to be relevant to junior high school students were prepared for each factor. The PMA index was compared according to the response for each factor. Furthermore, the response result for each question item in each factor was quantified, and path analysis was conducted based on the structure of the PRECEDE-PROCEED model using the total score as the score for each factor.

 As a result, the prevalence of gingivitis (those with PMA index of 1 or higher) was 87.5%, and the average PMA index score was 11.7. Most of the scores were 0 and the maximum index was 22, indicating a bimodal distribution. Comparison of the median PMA index for each response category revealed that only the “number of brushings” and “presence or absence of regular checkups” were question items that showed significant differences. Path analysis showed that the Goodness of Fix Index (GFI) which is the goodness-of-fit index of the model, was relatively strong at 0.975, and is very suitable as a structural equation. Reinforcement factors and enabling factors had a significant impact on health behavior factors, and behavioral factors affected the PMA index.

Abstract in Japaneses