Yoshikazu Okawa

Geographic distribution of specialist orthodontists and orthodontic providers in Japan

Abstract Objective This study aimed to clarify the geographic distribution of specialist orthodontists and dentists who provide orthodontic services in Japan. Methods We obtained data on the populations of 1750 municipalities in Japan in 2010 by referring to the census. We obtained data on the number of dentists who mainly provide orthodontic services (specialist orthodontists) and the number of dentists, including general dentists, who provide orthodontic services (orthodontic providers), by referring to the Survey of Physicians, Dentists, and Pharmacists. Furthermore, we referred to the directory on the website of the Japanese Orthodontic Society (JOS) to obtain data on JOS-qualified orthodontists. To assess the distribution of specialist orthodontists and orthodontic providers, we used Lorenz curves and Gini coefficients. Results The median value for the number of specialist orthodontists and number of JOS-certified orthodontists per 100,000 persons aged between 5 and 40 years old was 0, while that of orthodontic providers was 27.5. Gini coefficients for specialist orthodontists and JOS-certified orthodontists were 0.523 and 0.615, respectively. On the other hand, the Gini coefficient for orthodontic providers was 0.258. Conclusions Regional inequalities in the availability of specialist orthodontists are high, and medical access to specialist orthodontic services may be limited in areas other than urban districts. In municipalities with a population of fewer than 50,000 inhabitants, the number of specialist orthodontists was very low, but orthodontic providers were relatively evenly distributed. Our research results suggested that studying the distribution of specialist orthodontists and orthodontic providers can provide valuable information for developing dental care policies.