Trends in Denture Insurance Claims and Their Association With Socioeconomic Indicators and Population Aging in Japan.

OBJECTIVES

To describe nationwide temporal trends in insurance-covered denture claims in Japan and examine their associations with prefectural socioeconomic indicators and population aging using the National Database of Health Insurance Claims and Specific Health Checkups (NDB).

BACKGROUND

Japan is experiencing rapid population aging while tooth retention among older adults is improving. How these demographic and oral-health changes are reflected in the provision of insurance-covered complete dentures and removable partial dentures (RPDs) remains unclear.

MATERIALS AND

METHODS

A prefecture-level time-series analysis of NDB dental claims from 2013 to 2018 was conducted. The primary outcome was the annual number of total denture claims per dental clinic. Category-specific claims per clinic were also analysed for resin-base complete dentures and resin-base RPDs replacing 1-4, 5-8, 9-11 or 12-14 missing teeth. Prefectural income per capita, gross domestic product (GDP) per capita, and the proportion of residents aged ≥ 65 years were linked with annual claim data. Temporal trends, Pearson correlations, and category-specific multivariable linear regression models adjusted for calendar year were examined.

RESULTS

Total denture claims per clinic declined nationwide during the study period, from an average of 177 to 159 claims per clinic; complete denture claims showed the largest decrease (16%). The proportional share of complete dentures decreased, whereas the share of RPDs replacing 1-4 missing teeth increased. Total denture claims per clinic showed moderate negative correlations with income per capita (r = -0.518) and GDP per capita (r = -0.411), and a weak positive correlation with the proportion of residents aged ≥ 65 years (r = 0.344). In category-specific multivariable models, the proportion of residents aged ≥ 65 years was positively associated with claims in all denture categories, and calendar year was negatively associated with claims.

CONCLUSION

Total insurance-covered denture claims per clinic declined in Japan during 2013-2018, with regional variation and a larger relative contribution of small-span RPD claims. These findings suggest that geriatric denture service planning should account for both population aging and regional socioeconomic context.