2026 Volume 76 Issue 3 Pages 173-181
In this study, we aimed to evaluate the accessibility of dental care services for the ≥75-year-old population across Japan using two indicators: a distance- and time-based accessibility index rate, relying on straight-line distances from dental clinics and automobile travel time accounting for road networks and topographical conditions (dAIR and tAIR-car), respectively. Moreover, we examined the associations of these indices with dental-care use rates and dental expenditure.
We used 500-m mesh population data for individuals aged at least 75 years from the 2020 Population Census, along with medical institution data from the 2020 National Land Numerical Information. In this analysis, we included a total of 68,806 dental clinics nationwide. Using ArcGIS Pro, we calculated the size of older adult populations living outside service catchment areas, defined by 16-km dAIR and 15-min tAIR-car.
The results indicated that, based on the nationwide average, 2.27% of the population aged ≥75 years resided outside a 15-min automobile catchment area. We observed higher tAIR-car values in prefectures such as Kochi, Iwate, Wakayama, and Akita, displaying high aging rates and challenging topographical conditions. Furthermore, the 15-min tAIR-car exhibited weak negative correlations with dental-care use rates and dental expenditures, suggesting that reduced geographic accessibility is associated with decreased dental-care service use.
This study represents an accessibility evaluation based on realistic travel feasibility, which is difficult to ascertain using conventional distance-based measures. Thus, the findings will hopefully contribute to a better understanding of the current state of dental care access among older adults.
