Background/Objectives: Health management in workers in the taxi industry is particularly challenging due to irregular working hours and the need to prevent fatal accidents. In addition, drivers in Japan are aging, and the early prevention of age-related deterioration in oral health is an increasingly important issue. The aim of this cross-sectional study was to investigate the relationships between oral diadochokinesis (OD), tongue pressure, and lip-seal strength in Japanese male taxi workers. Methods: Measurements of tongue pressure and lip-seal strength were performed by dentists using specialized equipment. OD was measured using the number of consecutive "Pa", "Ta", and "Ka" vocalizations that could be produced in 5 s. We performed multiple regression analysis to examine the effects of lip-seal strength and tongue pressure on OD. Results: The study included 437 participants, excluding 17 who could not complete all oral cavity measurements. Tongue pressure showed a significant positive correlation with "Pa", "Ta", and "Ka" (correlation coefficients: 0.527-0.680). Lip-seal strength was not significantly correlated with OD. Tongue pressure showed a significant positive correlation with "Pa", "Ta", and "Ka". In the results of multiple regression analyses without the elderly participants, tongue pressure was associated with "Pa" (β[95% confidence interval]: 0.574[0.304, 0.843]), "Ta" (0.436[0.231, 0.640]), and "Ka" (0.424[0.210, 0.639]), and lip-seal strength was associated with "Pa" (0.128[0.032, 0.224]) and "Ka" (0.083[0.006, 0.160]). Conclusions: OD may be associated with lip-seal strength and tongue pressure even without including elderly workers. Regardless of age, maintaining good OD may help maintain lip-seal strength and tongue pressure, which may play a role in reducing the risk of age-related oral disorders.
Keywords: Japanese; lip-seal strength; oral diadochokinesis; tongue pressure; workers.