Geographic distribution of dental specialists permitted to advertise dental practices in Japan.

Objective: The purpose of this study was to determine the geographic distribution of dental specialists permitted to advertise dental practices in Japan. Method: We identified the populations of 349 secondary medical zones nationwide from the 2015 population census, as well as the number of dentists in five specialties, namely oral surgeons, pedodontists, periodontists, dental anesthesiologists, and dental radiologists, who had been permitted to advertise dental practices, from a 2016 survey of physicians, dentists, and pharmacists. We determined the placement rate, Lorenz curve, and Gini coefficient for dentists in each specialty in order to describe their geographic distributions. Results: The placement rates of at least one of these types of dentist in each secondary medical zone were 73.9% for oral surgeons, 66.2% for pedodontists, 60.5% for periodontists, 31.8% for dental anesthesiologists, and 18.3% for dental radiologists. The Gini coefficients were 0.397, 0.400, 0.491, 0.650, and 0.761, respectively. Conclusion: The dentists in each specialty were few in number and were unequally distributed among the zones, but less so for oral surgeons and pedodontists. Dental anesthesiologists and radiologists were located primarily at university hospitals in urban areas and, therefore, were more unequally distributed. [ABSTRACT FROM AUTHOR]