Removable denture use, fit, and all-cause mortality in older adults with reduced occlusal support: The OHSAKA study

As the global population ages, tooth loss among older adults has become increasingly prevalent, impacting oral function and overall health. Although removable dentures have been used to improve masticatory function, the long-term effects of denture conditions on mortality are unclear.

The purpose of this clinical study was to clarify the association between removable denture condition and the mortality rate in older adults with reduced occlusal support.

This longitudinal study analyzed survival data (up to 2022) for 186893 individuals aged ≥75 years who underwent dental examinations through public healthcare services between 2018 and 2020. The participants were categorized into 10 groups (A1 to A3, B1 to B4, and C1 to C3) based on their occlusal support status using the Eichner index. Denture conditions were assessed by private practice dentists and classified into 3 categories: well-fitting, poorly fitting, and not used. Cox proportional hazards regression analyses were conducted to examine the association between denture conditions and mortality by considering the following control variables: age, sex, history of chronic diseases (hypertension, diabetes, hyperlipidemia, and dementia), smoking habits, and body mass index for the entire study population and within each of the B1 to B4 and C1 to C3 groups.

Significantly higher hazard ratios (HRs) for mortality were observed with occlusal support deterioration, poorly fitting dentures, and nonusage, with the peak observed in the C3 group with no dentures. The HRs (with 95% confidence intervals) of well-fitting dentures were consistently the lowest across all groups as follows: 0.98 (0.90 to 1.06) in B1, 1.02 (0.95 to 1.10) in B2, 1.11 (1.03 to 1.19) in B3, 1.14 (1.07 to 1.22) in B4, 1.15 (1.05 to 1.26) in C1, 1.28 (1.21 to 1.37) in C2, and 1.58 (1.46 to 1.72) in C3, with the A1 to A3 group as the reference. Poorly fitting or no dentures were associated with increased HRs in the Eichner groups B3 to C3, compared with well-fitting dentures.

This large population-based cohort study found that well-fitting dentures were associated with lower mortality risk in older adults with reduced posterior occlusal support. Nonusage or poorly fitting dentures were associated with an increased risk of mortality as occlusal support deteriorated.