Age- and sex-related variations in jaw-opening and tongue functions in healthy adults.

OBJECTIVES

To characterize age- and sex-related variations in jaw-opening performance and tongue function, and to establish physiological reference ranges in healthy adults.

DESIGN

A cross-sectional study was conducted in 298 healthy participants (129 males, 169 females), aged 17-85 years. Maximum interincisal opening (MIO), tongue range of motion ratio (TRMR), maximum tongue strength, and tongue endurance were assessed using standardized protocols. Participants were stratified by age, and reference ranges were calculated as mean ± 2 SD. Associations across age groups, sex, and body mass index (BMI) were examined using correlation and regression analyses.

RESULTS

Maximum tongue strength declined progressively across age groups in both sexes, decreasing by approximately 4.9 kPa per decade in females and 4.7 kPa in males, with substantially lower values in adults aged ≥ 65 years. Tongue endurance remained largely stable across age groups, showing only a mild upward trend in older females. MIO demonstrated an age-related reduction in males, whereas TRMR exhibited minimal age-dependent variation. Regression analysis identified age as a significant predictor of maximum tongue strength, while endurance and mobility were not significantly associated across age groups or BMI.

CONCLUSIONS

Age-related reductions in tongue strength represent the most prominent physiological change in orofacial motor performance, whereas tongue mobility and endurance remain relatively preserved. The reference values established in this study provide clinically relevant benchmarks for future research on oral motor aging and craniofacial functional assessment.