Oral diadochokinesis, tongue pressure, and lip-seal strength in Japanese workers: A cross-sectional study

This cross-sectional study investigated the correlation between lip-seal strength, tongue pressure, and oral diadochokinesis (OD) in Japanese workers. The relationships between lip-seal strength, tongue pressure, and OD by age groups were investigated using multiple regression analyses on 496 workers. OD was measured using the number of consecutive "Pa," "Ta," and "Ka" vocalizations that could be produced in 5 s. In this study, 478 participants (437 males and 41 females) were included in the analysis after excluding 18 participants who could not complete all oral cavity measurements. This study revealed a significant positive correlation between "Pa," "Ta," and "Ka," with correlation coefficients of 0.500-0.665. Lip-seal strength only significantly correlated positively with "Pa"; however, tongue pressure significantly correlated positively with all of "Pa," "Ta," and "Ka" vocalizations. Regarding body mass index (BMI), no significant relationship with either "Pa," "Ta," or "Ka" was observed. As a result of aging, "Ta" and "Ka" showed a significant negative correlation with age. Multiple regression analyses, which included age, sex, BMI, alcohol consumption, and smoking, revealed a strong association between "Pa," "Ta," and "Ka" and lip-seal strength. However, only "Pa" showed a significant correlation with tongue pressure. Even in young and middle-aged adults, OD may be associated with lip-seal strength and tongue pressure. Measuring OD through dental screening of workers will help prevent the disease across a wide age range.