Analysis of Correlation among Oral Environment, Oral Myofunction, and Oral Microorganisms

Background: Factors affecting oral function include tooth number, oral muscle strength, and oral diseases. This study aimed to investigate the relationship among oral environment, muscle, and microbiology. Methods: Fifty-six elderly individuals in a day care center were included in the study. The survey regarding tongue and lip muscle strength and oral microorganisms was conducted from November to December 2018. Results: Tongue and lip muscle strength were greater in men than women (p>0.05). Tongue muscle strength was greater in the ${\leq}80-year-old$ group ($34.94{\pm}9.85$) than the ${\geq}90-year-old$ group ($25.57{\pm}7.54$) (p<0.05). Tongue muscle strength and lip muscle strength were greater in the ${\geq}15$ functional teeth group ($34.08{\pm}9.31$ and $9.25{\pm}1.63$, respectively) than in the <15 functional teeth group ($28.08{\pm}7.53$ and $7.76{\pm}1.51$, respectively) (p<0.05). Age was significantly correlated with functional tooth number, denture use, and tongue muscle strength. The number of functional teeth was positively correlated with tongue muscle strength, lip muscle strength, and oral microorganisms. Denture use was negatively correlated with tongue and lip muscle strength. Tongue muscle strength was significantly correlated with lip muscle strength. The number of Eubacterium nodatum was higher in men than women. The number of Parvimonas micra and Enterococcus faecalis was higher in the groups with ${\geq}15$ functional teeth, denture use, and greater tongue and lip muscle strength. The number of Lactobacillus casei was higher in the group that uses dentures and with greater tongue strength. Conclusion: Oral microbiology is more important in oral environment and management than oral muscle function. The correlation between oral muscle and oral microorganism requires further study. Therefore, oral care training should be conducted to improve the oral care practice of elderly individuals, maintain oral health through oral care, and prevent the decrease in saliva secretion by aging.