Handgrip strength and dental plaque removal performance in older primary care patients: A cross-sectional study

Background: A cross-sectional study was conducted at a primary care unit and general practitioner clinic in a tertiary teaching hospital in Hat Yai, Songkhla, Thailand, to evaluate the effect of hand grip strength on maintaining oral hygiene in older adults. Method: Participants completed a questionnaire, performed a brushing task on a force-sensor–equipped dental model, and had plaque stained before brushing while being video recorded. The primary outcome was plaque removal performance. Multivariable logistic regression identified factors associated with inadequate plaque removal, and sex-specific grip strength cut-off points were determined using receiver operating characteristic analysis. Results: Among 116 older adults, 31.0% demonstrated inadequate plaque removal. Low grip strength was strongly associated with poor performance (adjusted OR 8.02; 95% CI 2.19–29.35). Higher pre-brushing plaque index (34.52; 95% CI 6.29–189.33) and lower brushing force on the dental model (0.05; 95% CI 0.01–0.48) were also significant factors. Optimal grip strength cut-off points for predicting inadequate plaque removal were 31.7 kg for males (73.3% sensitivity, 70.6% specificity) and 21.5 kg for females (76.2% sensitivity, 46.0% specificity). These values exceeded current sarcopenia screening cut-offs, which showed high sensitivity but low specificity for predicting inadequate plaque removal. Conclusion: Low grip strength and reduced brushing force were associated with inadequate plaque removal in older adults. While existing sarcopenia grip strength cut-offs can sensitively identify those at risk of poor plaque removal, higher cut-off values may improve specificity for oral hygiene performance. Keywords: Brushing force, Dental plaque removal, Hand grip strength, Older adults, Sarcopenia, Thailand