Are Public Oral Care Services Evenly Distributed?—Nation-Wide Assessment of the Provision of Oral Care in Japan Using the National Database of Health Insurance Claims

The provision of oral health care services is one of the global challenges under the realization of universal health coverage in many countries. Despite the increasing importance of oral health care in an aging society, the disparities in the provision of oral care in Japan have not been clarified. Therefore, this study investigated the status of oral and dental care provision using the National Database of Health Insurance Claims and Specific Health Checkups (NDB) at the level of prefectures and secondary medical care areas. Additionally, a multiple regression model was applied to identify the influence of human resources in oral care services and economic factors on the standardized claims data ratio (SCR) of total dental receipts. The results showed that the total amount of oral care provided tended to be higher in metropolitan areas, with bimodal peaks in children aged 5–9 and adults in their 70s. The SCR for dental caries showed little difference nationally, but SCR for periodontal disease tended to be higher in prefectures including metropolitan areas. In a multiple regression model, the number of dentists and prefectural income per capita influenced the SCR of total dental receipts. In secondary medical care areas, some depopulated areas are supplemented by adjacent areas. These results suggest that oral health care services in the national health insurance system are generally well provided; however, they are likely to be influenced by human resources and economic disparities, and regional differences may occur in the care of periodontal diseases.