This paper is the second part of a report on recent scientific evidence regarding fluoride application. 1. The effectiveness of school-based fluoride mouthrinse in Japan: We explained that the effectiveness of health policies in real-world settings could not be evaluated based on randomized controlled trials alone, and school-based fluoride mouth rinse is necessary as a population strategy to reduce health inequalities. 2. Chlorhexidine application for caries prevention and the safety of fluoride toothpaste with titanium materials for anaphylactic shock: We reviewed the scientific evidence on the caries-preventing effects of and adverse events caused by chlorhexidine. 3. Fluoride application and allergies/anaphylaxis: We reported the unlikeliness of fluoride application causing anaphylactic shock, and stated that fluoride should be applied carefully to prevent acute fluoride toxicity. 4. Fluoride application and scientific evidence on caries prevention for infants and toddlers: We explained that “evidence of the cause of disease” and “evidence of preventing the cause” needed to be considered separately. 5. Necessity of advocates for fluoride application, including water fluoridation: We explained that it is necessary to continue to advocate for public-based scientific evidence as the role of experts in public health policy in the group decision-making process.

 This study was conducted to clarify whether the chewing status is associated with life expectancy in prefectural populations of Japan, with a focus on the involvement of lifestyle factors.

 Based on distributions of prefecture-, sex-, and age-specific items obtained from the 8th National Database of Health Insurance Claims and Specific Health Checkups of Japan (NDB Open Data for 2020), proportions of individuals with chewing difficulty, drug use, poor lifestyle habits, and obesity were calculated, with age-adjustment performed using the direct method. The questionnaire answers: “Sometimes it is difficult to chew due to dental problems” and “I can hardly chew”, were considered to indicate chewing difficulty. Pearson’s correlation coefficient (r) was used to analyze the relationship between the proportion of individuals with chewing difficulty and life expectancy, as well as the proportion of each item noted; then, multiple linear regression analysis was conducted with life expectancy as the dependent variable and items significantly correlated with life expectancy as explanatory variables, and standardized regression coefficient (β) values were calculated.

 The proportion of both males and females with chewing difficulty showed a significant negative correlation with life expectancy (males: r=-0.501, p<0.001; females: r=-0.442, p=0.002), while it was significantly positively correlated in both sexes with antihypertensive drug use, hypoglycemic drug use, current smoking habit, and obesity. Variables associated with life expectancy for males were chewing difficulty (β=-0.241), antihypertensive drug use (β=-0.348), and alcohol consumption (β=-0.429); those for females were current smoking habit (β=-0.317), eating fast (β=0.347), and obesity (β=-0.388).

 Life expectancy tended to be lower for both males and females in prefectures with a higher proportion of individuals exhibiting chewing difficulty. Independent of lifestyle factors, there was a negative association of chewing difficulty with life expectancy in males, but not females.

Abstract in Japaneses

Abstract in Japaneses

 A 45-year-old male patient visited a dental clinic with the chief complaint of buccal gingival pain in areas 34 and 36 in December 2016. Examination revealed a white reticular area in gingiva 34 and 36, which was diagnosed as oral mucosal disease (white lesion-like oral lichen planus) with moderate periodontitis. The mean periodontal pocket depth was 3.16±0.26 mm. The prevalence of periodontal pocket depths ≥ 4 mm was 8%. The rate of bleeding during probing was 36%. The periodontal inflamed surface area (PISA) was 590.3 mm² at the initial visit. There was no tooth movement. Basic periodontal treatment was initiated. At the second visit, when the pain at 34 and 36 was relieved, health guidance, including brushing using the toothpick method, was given. During periodontal treatment, the dentist also performed tooth brushing using the toothpick method, and prescribed steroid ointment and benzethonium chloride gargle. The patient’s oral mucosal disease was in remission by October 2021. At the final evaluation in October 2022, the mean periodontal pocket depth was 3.08±0.38 mm. The prevalence of periodontal pocket depths ≥ 4 mm was 4%, and rate of bleeding during probing was 0%. PISA had improved to 0 mm². In this case, oral health management involving professional tooth brushing including the toothpick method and oral health instruction led to remission of the patient’s oral mucosal disease.