Global Neglect of Dental Coverage in Universal Health Coverage Systems and Japan's Broad Coverage

Oral diseases, including dental caries, periodontal disease, and tooth loss, are among the most common diseases in the world, representing a significant burden on global health, social activities, and the economy. The disability-adjusted life year (DALY) due to oral diseases is substantial. Because of their high prevalence and progressive nature, direct and indirect global costs of oral diseases reached $356.80 billion and $187.61 billion, respectively, in 2015. However, oral health care is often separated from primary care services and neglected in universal health coverage systems. Integrating dental care into universal health coverage systems is required to improve access to dental care and dental health. Advanced technologies and specialist-based dental interventions impose high dental care costs on patients. These high costs contribute to social inequalities in dental care use. In Figure 1, to briefly overview the Japan’s situation in the world, we show the univariate association between out-of-pocket dental expenditures and the average dental visit frequency per person in 2011, or the nearest year for which data were available, in country-members of the Organisation for Economic Co-operation and Development (OECD). These out-of-pocket dental expenditures are likely to vary between countries because of differences in coverage schemes. Dental visit frequencies were higher in countries with lower dental expenditures. Although the figure shows a univariate association that does not consider other factors, the degree of insurance coverage is reported to affect dental visits. Therefore, improving coverage and, thus, lower outof-pocket dental expenditures are required to increase dental care use.