Lip Pressure, Bite Force and Denture Use as Predictors of Oral Frailty in Physically Active Older Adults: A Cross-Sectional Study

Background: Oral frailty is an emerging determinant of late-life disability. While objective functional measures have been proposed as key indicators, their combined role in predicting frailty among physically active older adults remains unclear. Therefore, this study aimed to investigate the association between the presence of oral frailty and lip pressure, bite force, and denture use. Methods: This cross-sectional study included 192 participants aged 60 years or older from Brazil (n = 131) and Portugal (n = 61), all physically active and with ≥20 natural or rehabilitated teeth. Data were collected through a questionnaire on sociodemographic data and the Oral Frailty Index-8. The clinical assessment included lip pressure, bite force, and denture use. Multiple logistic regression identified independent predictors; model fit and discrimination were examined using the Hosmer–Lemeshow test and ROC curve. Results: Participants were mainly female (83.3%), mean age ≈72 years; 76% used dentures and frailty prevalence was ≈49%. Higher lip pressure (OR = 0.986, 95% CI = [0.973–0.999]) and higher bite force (OR = 0.925, 95% CI = [0.885–0.967) were independently protective, whereas denture use (OR = 6.898, 95% CI = [2.994–15.895]) markedly increased oral frailty odds. The model showed good discrimination (AUC 0.779). Conclusions: Even small increases in lip pressure and bite force reduced the likelihood of frailty, while denture use identified individuals at substantially higher risk. These findings highlight orofacial muscle strength and masticatory capacity as core components of oral frailty and support incorporating lip pressure and bite force testing into multidimensional frailty assessment and targeted rehabilitation.