Oral health impacts systemic health. Therefore, oral care is an important consideration in maintaining quality of life (QOL). Previously, maintenance and improvement of oral hygiene was considered essential for achieving oral health. In addition to oral hygiene, oral care in terms of oral function is now considered to maintain QOL. Ingestion of exogenous nutrients via the oral cavity is fundamental to the function of all higher animals, not only human beings. Chewing and swallowing processes are critical for normal food intake, and adequate saliva supply and oral care to allow proper functioning of these processes are indispensable for maintaining QOL. In this review, we will summarize the relationship between chewing and swallowing and effects of saliva secretion on these functions, and discuss methods to maintain ingestion of exogenous nutrients and prevent swallowing problems, especially in elderly people.

Background: Self-rated oral health is a valid and useful summary indicator of overall oral health status and quality of life. However, few studies on perception of oral health have been conducted among Japanese young adults. This study investigated whether oral health behavior, subjective oral symptoms, or clinical oral status were associated with self-rated oral health in Japanese young adults. Methods: This cross-sectional survey included 2,087 students (1,183 males, 904 females), aged 18 and 19 years, at Okayama University, Japan. A self-administered questionnaire was distributed and an oral examination was performed. Results: In a structural equation modeling analysis, the score of decayed, missing and filled teeth (DMFT) significantly affected self-rated oral health (p <0.05) and the effect size was highest. Malocclusion, subjective symptoms of temporomandibular disorders (TMD) and stomatitis, and poor oral health behavior significantly induced self-rated poor oral health with small effect sizes (p <0.05). Clinical periodontal conditions and Oral Hygiene Index-simplified were not related to self-rated oral health. Conclusion: Self-rated oral health was influenced by subjective symptoms of TMD and stomatitis, oral health behavior, the score of DMFT, and malocclusion. The evaluation of these parameters may be a useful approach in routine dental examination to improve self-rated oral health in university students.

The present study aimed to elucidate the associations among self-rated oral health, clinical oral health status, oral health behaviors, subjective oral symptoms, and oral health-related quality of life (OHRQoL) in a group of Japanese university students. Of 2051 participants, 2027 (98.83%) students received an optional oral examination and answered a questionnaire including items regarding age, sex, self-rated oral health, oral health behaviors, subjective oral symptoms, and OHRQoL [The Oral Health Impact Profile (OHIP)-14]. On oral examination, the decayed, missing, and filled teeth (DMFT) score, Community Periodontal Index (CPI), the percentage of teeth showing bleeding on probing (%BOP), and malocclusion were recorded. Structural equation modelling (SEM) analysis was used to test associations. The mean score (± SD) of OHIP-14 was 1.92 ± 5.47. In the SEM analysis, the final model showed that self-rated oral health, oral pain, malocclusion, and the DMFT score were directly associated with the OHRQoL, and subjective symptoms of temporomandibular disorders (TMD) and recurrent aphthous stomatitis were both directly and indirectly associated (p < 0.05). CPI, %BOP, and oral health behaviors were excluded from the final model. OHRQoL was associated with self-related oral health, subjective symptoms of TMD, oral pain and stomatitis, DMFT, and malocclusion in this group of Japanese university students.

Aspiration is increasingly recognized as a major risk for pneumonia, but a potential link between wearing dentures and incident pneumonia with aspiration risk is unclear. The aim of this study was to investigate whether denture wearing moderates the association between aspiration risk and incident pneumonia in older adults. We used prospective cohort data of 156 residents aged >70 years from eight nursing homes in Aso, Japan. Aspiration risk was evaluated using the modified water swallowing test. During a 1-year follow-up (2014 to 2015), information on incident pneumonia was obtained from nursing home medical records. During follow-up, pneumonia developed in 7.1% of participants. In the multivariate-adjusted Cox proportional hazards model, after adjusting for potential confounders, aspiration risk was independently associated with a 4.4-fold higher hazard ratio (HR) of incident pneumonia (95% confidence interval, CI, 1.16–16.43). The difference in the risk of incident pneumonia between subjects with aspiration risk who were wearing dentures and those not at risk of aspiration was not significant, whereas those with aspiration risk without dentures had a 7.3-fold higher HR of incident pneumonia than those not at risk of aspiration (95% CI, 1.02–52.63). Denture wearing might partially moderate the increased risk of incident pneumonia associated with aspiration risk.

Background: Toothbrushing is a health-related lifestyle habit and has been reported to contribute not only to oral health but also to some parameters of general health; however, little research has been conducted to understand the association of the frequency and timing of toothbrushing with the development of comprehensive metabolic abnormalities considering oral health condition. In this study, using longitudinal data, we examined this association in Japanese adults, adjusting for periodontal condition.Methods: A 5-year longitudinal study was performed with 4,537 participants between 35 and 64 years old who underwent an annual dental examination in both 2003 and 2008. Data about toothbrushing habits and metabolic abnormalities such as obesity, hyperglycemia, diabetes, hypertension, hypertriglyceridemia, and low levels of high-density lipoprotein-cholesterol were analyzed using Poisson regression analysis.Results: The percentage of participants with a toothbrushing frequency ≤1 time/day was 29.4%, and that for those not brushing their teeth at night was 21.4%. The incidences of obesity and hyperglycemia after 5 years were 5.5% and 28.4%, respectively. A toothbrushing frequency ≤1 time/day was associated with development of obesity [prevalence rate ratio (PRR) = 1.77; 95% confidence interval (CI): 1.12–2.80], after adjusting for periodontal condition and potential risk factors. A significant association between not brushing teeth at night and hyperglycemia (PRR = 1.30; 95% CI: 1.02–1.66) was observed in participants with toothbrushing frequency of 1 time/day. No association was found between toothbrushing habits and other metabolic abnormalities.Conclusions: This study suggests that toothbrushing habits are associated with the development of obesity and hyperglycemia.