Posterior Teeth Occlusion and Functional Dependence Among Japanese Older Adults

Objectives: Aging-related functional decline leads to a loss of independence, and it can be a predictor of morbidity and mortality. The early identification and subsequent reduction of modifiable risk factors causing functional decline are essential for extending the healthy life-span in currently aging societies. This study examined whether posterior teeth occlusion is associated with functional dependence regardless of the number of natural teeth among Japanese nursing home residents.
Methods: This cross-sectional study included 234 residents aged more than 60 years from eight nursing homes in Aso City, Japan, from February 2014 to June 2014. Functional dependence in basic activities of daily living was measured using the Barthel index, and the primary outcome was independence for essential personal care (Barthel index ≥ 60 points). Posterior teeth occlusion was assessed by a dentist using the total number of functional tooth units, depending on the number and location of the remaining natural and artificial teeth on implant-supported, fixed, and removable prostheses. Binomial logistic regression models were used to assess univariate and multivariate associations between the total number of functional tooth units and independence for essential personal care. Models were adjusted for the number of natural teeth, demographic characteristics, socioeconomic status, health behaviors, and comorbidities.
Results: Independence for essential personal care was found in 14.1% of subjects. Greater total numbers of functional tooth units were significantly associated with greater odds of independence for essential personal care (odds ratio = 1.12; 95% confidence interval = 1.01–1.24). The positive association remained significant after adjustment for the number of natural teeth and other possible confounders (odds ratio = 1.14, 95% confidence interval = 1.01–1.29).
Conclusions: Posterior teeth occlusion was independently associated with functional dependence among older nursing home residents in Japan. The maintenance and restoration of posterior teeth occlusion may have preventive effects against late-life functional decline.