Toshihiro Ansai

九州歯科大学では，学部学生のリサーチマインド向上を目的として，平成18（2006）年度より「研究室配属」をカリキュラムに組み込んでいる．本稿では，これまでの研究室配属を振り返るとともに現状と課題について整理した．学生の配属先決定や配属期間，発表会の実施，そしてオンラインアンケートの集計を行った．研究テーマ不足と受入れ学生数の不均衡が依然課題として残る一方，発表会の学生主体運営により質疑応答の活性化が見られた．アンケートでは大部分の学生から実施内容に関して肯定的な評価が得られ，対応した教員に対する評価も高かった．今後は，配属学年（2年生）の妥当性検討も含めて，学習効果の向上ならびに基礎研究者の育成に向けた実施内容の改正を検討する必要がある．

The relationship between sarcopenic obesity and masticatory function is poorly understood. This study aims to explore this association in community-dwelling individuals aged 75 years or older. This study analyzed data from 236 community-dwelling adults aged 75 years or older. Masticatory function was assessed using spectrophotometric measurement of gum color differences before and after chewing color-changeable gum (ΔE*ab). Participants were categorized into tertiles of masticatory function based on their ΔE*ab values. The tertiles were defined as low, intermediate, and high. Sarcopenic obesity was assessed using the Consensus statement of the Japanese Working Group on Sarcopenic Obesity. Bayesian multinomial logistic regression was employed to examine the relationship between masticatory function and sarcopenic obesity. The prevalence rates for obesity, sarcopenia, and sarcopenic obesity were 15.3%, 24.2%, and 9.7%, respectively. After adjusting for covariates, participants with high masticatory function had a significantly lower posterior estimate of sarcopenic obesity (posterior estimate: −1.83 [95% credible interval: −3.66, −0.22]) and sarcopenia (posterior estimate: −1.97 [95% credible interval: −3.37, −0.72]) compared with participants with low masticatory function. However, no significant associations were observed between masticatory function and obesity. These findings suggest that high masticatory function is associated with a significantly lower prevalence of sarcopenic obesity in older adults.

Nanobubbles of gas remain dissolved in water for longer periods than ordinary bubbles, and exhibit unique physicochemical and biological properties. As a result, nanobubble water (NBW) is finding widespread use many applications, such as cleaning in the industry and purification of lake water. The ozone NBW (O₃-NBW), in particular, has been used in clinical dentistry; however, it has several disadvantages, including the instability of ozone, which is spontaneously converted to molecular oxygen (O₃ to O₂), and its broad range of antibacterial activity, which can disrupt the oral microbiota. Therefore, the use of NBW in dental medicine requires greater evaluation. Here, we examined the effects of oxygen and hypochlorite NBW (O₂-NBW and HOCl-NBW, respectively) on the microbiota in human saliva in 16 male patients (35–75 years old; median: 53.5 years) using multiple assays, including next generation sequencing analysis. 16S rRNA gene sequencing revealed no significant changes in both alpha-diversity and beta-diversity. Principal Coordinate Analysis (PCoA) revealed two subclusters in both unweighted and weighted UniFrac distances. Overall, the results revealed that HOCl-NBW exposure of saliva may lead to inhibition or delay in oral biofilm formation while maintaining the balance of the oral microbiome. These results can lead to the development of a novel type of mouthrinse for prevention of oral infectious diseases.

Background: Procrastination is a psychological trait that causes individuals to put off doing things that need to be done. It has recently shown to result in the worsening of symptoms due to delays in seeking medical care. However, it is not clear how perception of dental disease influences dental visits. This study examined the associations of procrastination and personality traits with delayed dental visits for both acute and chronic conditions.Methods: Of 599 university students queried, the data of 549 subjects (mean age 19.7 years) were analyzed. A general procrastination scale (GPS), the Big Five personality traits, and oral hygiene habits were used for analysis. The participants were asked about illness awareness conditions related to dental disease, perception of pain in the oral region due to acute oral symptoms and chronic symptoms. The participants were asked the number of days until they decided that treatment was required. Based on the bimodal shape of the distribution, those who answered at least eight days for acute or chronic conditions were classified as the procrastination (P) group and the others as the non-procrastination (Non-P) group.Results: Significant differences in GPS scores were found between the groups for both acute and chronic conditions, with significant differences in the Big Five traits of extraversion, agreeableness, and neuroticism for an acute condition and extraversion, openness, and neuroticism for a chronic condition. There were no significant differences regarding oral hygiene habits between the groups for either condition. Next, using a Bayesian network, the probabilistic causal relations among procrastination, the Big Five traits, and delays in dental visits for both acute and chronic conditions were analyzed. Among the Big Five traits, conscientiousness and neuroticism were directly related to GPS score. Interestingly, agreeableness was directly related to delays in dental visits only for an acute condition and showed a negative effect, while dental student status had a positive effect on delays in dental visits.Conclusions: The results showed that procrastination and dentistry department are factors that directly influence delays in dental visits, while agreeableness, a Big Five trait, has a negative effect on individuals with an acute condition.

While occlusal status has been reported to be related to cognitive function, little is known about the influence of age on that relationship. The present study examined the associations of tooth loss and occlusal status with dementia in the older people, as well as the effects of age on those relationships. A total of 196 older participants (median age: 84 years) were enrolled. Occlusal status was assessed using functional tooth units (FTU), calculated based on the number of paired natural or artificial teeth. Logistic regression analysis was then performed using dementia as the objective variable, and FTU or number of teeth as explanatory variables. The results showed that higher FTU was associated with lower risk of dementia. Furthermore, when stratified by median age, the association was greater for those aged less than 84 years. On the other hand, there was no significant association of number of present teeth with dementia. These results suggest that the risk of dementia is lower for individuals with better occlusion and that occlusal factor may have a greater effect on dementia onset in younger older people. It is thus recommended that both occlusal function and age be incorporated as factors in programs developed for dementia prevention.

Approximately 20% of the community-dwelling Japanese elderly (≥65 years) experience falling annually, with injury frequency rising with age. Increased nursing home admission/hospitalization risk influences healthy aging and QOL. Nutrition for musculoskeletal health is necessary, though the relationship of falling with nutritional status in the elderly is largely unknown. We investigated falling incidents and nutritional status, including a Japanese-style diet in a community-dwelling cohort. Using a cross-sectional design, 186 subjects (median age 83.0 years, males/females 67/119) were analyzed. Oral and systemic health conditions were assessed. A brief-type self-administered diet history questionnaire (BDHQ) was given for nutritional status. Analysis of covariance (adjusted for gender, age, BMI, articular disease/osteoporosis history, present tooth number, educational level) and the Japanese-Mediterranean diet (jMD) score adapted for Japan were used. The jMD score and falling incidents were significantly associated, with point increases related to a significantly decreased falling risk of 28% (OR: 0.72; 95%CI: 0.57–0.91). Of the 13 jMD food components, fish, eggs, and potatoes had a significant relationship with reduced falling, while significant associations of intake of animal protein, potassium, magnesium, zinc, and cholesterol (p < 0.05) were also observed. The results suggest that the jMD dietary pattern is an important factor for the prevention of falling incidents in elderly individuals.

Background: It is well known that cigarette smoking is the main health hazard in middle-aged people.However, data regarding smoking and health in old-aged people are limited, especially in the Japanese population. Objective: The present study aimed to investigate the influence of smoking on mortality in the elderly Japanese population. Methods: A cohort of 690 individuals of 80 years of age were categorized into 3 groups: non-smokers, ex-smokers and current smokers. The adjusted mortality after 4 years was compared among the 3 groups. The possible influence of smoking status on the cause of death was also investigated. Results: The overall mortality was significantly higher in males [relative risk (RR): 2.3, 95% confidence interval (CI): 1.0–5.2] and females (RR: 4.2, 95% CI: 1.9–9.5) in the current-smoker group than in the non-smoker group. The risk of any-cause mortality in the ex-smoker group was not statistically different from that in the non-smoker group. In males, current smokers died of cancer more frequently than non-smokers (RR: 10.7, 95% CI: 1.3–90.8). Cardiovascular disease was a significant cause of death in female current smokers (RR: 5.2, 95% CI: 1.6–16.9). This difference in mortality was not observed between groups of non-smokers and ex-smokers of both genders. In male smokers, there was a positive relationship between the daily amount of consumed cigarettes and overall mortality. Conclusion: Smokers should be encouraged to stop smoking, since habitual smoking increases the risk of mortality even in old age.

This study investigated whether oral malodour with plaque-related periodontal disease was associated with the prevalence of periodontopathic bacteria in saliva and tongue debris. The subjects were 30 patients who visited the Breath Odour Clinic. An oral examination was performed at baseline and two months after periodontal treatment, and included measuring the volatile sulphur compounds (VSCs) in mouth air. The proportions of five periodontopathic bacteria versus all bacteria in saliva and tongue debris were determined using real-time polymerase chain reaction. The subjects were classified into four groups based on the existence of VSCs above the organoleptic threshold level (TVSC) and a periodontal pocket ⩾4 mm (PD4). At baseline, the group with TVSC/PD4 had higher proportions of periodontopathic bacteria in saliva compared to those with TVSC/no PD4 and no TVSC/no PD4, but there were no differences in the proportions in tongue debris among the four groups. At follow-up, the proportion of periodontopathic bacteria in the saliva of the group with TVSC/PD4 was significantly reduced, as compared to that at baseline, and the VSCs and periodontal health improved. The results suggested that the reduction in VSCs in mouth air of subjects with periodontal disease might be associated with the prevalence of periodontopathic bacteria in saliva.