Association between tongue muscle strength and masticatory muscle strength

Background The tongue is responsible for compressing food against the palate and squeezing it into the pharynx during the oral preparatory phase of swallowing. Tongue pressure (TP), an indicator of tongue muscle strength, has been observed to decline with age; maximum occlusal force (MOF), an indicator of chewing ability, is correlated with TP. However, no study has investigated the relationship between TP and MOF. Objective To investigate the correlation between TP and MOF according to age in healthy individuals. Methods We retrospectively collected handgrip strength (HGS), body mass index (BMI), TP, MOF and tooth loss data for 785 healthy participants (305 men, 480 women). All subjects had either unilateral or bilateral occlusal support, regardless of the presence of dentures or natural teeth. The participants were divided into two groups: an adult (20s-50s, n = 497) group and an elderly (60s-80s, n = 288) group. Multivariate linear regression analysis was performed to determine significant independent variables associated with TP in both groups. Results Multivariate analysis revealed that TP was significantly associated with age (beta = -0.153), BMI (beta = 0.205), HGS (beta = 0.298) and MOF (beta = 0.239) in the adult group (all P < 0.001) and with age (beta = -0.266, P < 0.001), BMI (beta = 0.160, P = 0.005), MOF (beta = 0.217, P = 0.001) and tooth loss (beta = 0.156, P = 0.011) in the elderly group. Conclusions As age and MOF are each associated with TP in both elderly and adult patients, age-related TP decline can be prevented with routine lingual exercises, even before the onset of old age. Additionally, MOF deterioration may indicate a decline in TP for elderly.