Using a geographical information system to map the distribution of dentists in Ohio

Studies have reported that dental care is the highest unmet health care need in the United States and have evaluated this in terms of individual determinants of access and utilization. None of these studies took into consideration the provider issues of availability and accessibility or of spatial relations. The aim of this study was to analyze issues of provider availability and accessibility in Ohio using a geographical information system, or GIS.

Three Ohio databases were geocoded using GIS software. The databases included all 6,132 dentists licensed to practice in Ohio, 1,898 dentists who had billed the state Medicaid program in 1998 and safety-net clinics that provided free or low-cost care. Each practitioner was mapped at the county and ZIP code levels.

Results are reported using maps at the county and ZIP code levels. The maps showed that 69.4 percent of dentists practiced in 12 metropolitan counties, 14 percent in 17 suburban counties and 16.6 percent in 59 rural counties (rural non-Appalachian counties plus Appalachian counties). In Appalachia, the dentist-to-population ratio was about one-half that of the metropolitan counties.

Obvious disparities exist in the distribution of dentists in Ohio, particularly in rural and Appalachian counties. The need to increase the availability of dentists in these counties is evident.

GIS is a useful tool for evaluating provider distribution and availability and planning programs to attract dentists to areas with small numbers of dentists.