CHARLOTTESVILLE, Va. (AP) — Many Virginians don't have access to dental care because of costs and a lack of dentists, according to a new study by two University of Virginia economists.

Cost is the greatest barrier. Those least likely to visit a dentist are low-income residents without insurance or who have low-cost public health care. Virginia's Medicaid program generally limits dental care for low-income adults to emergency services, the study said.

There also are racial and geographical disparities in access to care.

The study found that black Virginians were less likely to visit a dentist or dental clinic in the past year than other groups. Residents of the state's western and southern regions, which are more rural, were less likely to have received dental care than those in the urbanized northern and eastern regions.

More than than 15 percent of Virginia's population lives in areas designated by the federal government as dental Health Professional Shortage Areas. The designation means there is an insufficient number of dentists to serve the population's needs.

The study was conducted Terance Rephann of U.Va.'s Weldon Cooper Center for Public Service and Tanya Wanchek of the School of Medicine.

Rephann and Wancheck say access to dental care could be improved by expanding dental hygienists' services and easing requirements for supervision by dentists.

"In particular, allowing hygienists to offer fluoride varnish and routine cleaning without supervision by a dentist has the potential to generate significant health improvements at low cost," Rephann and Wancheck wrote. "The resulting increase in visits by those previously not receiving care has a very important side benefit. The hygienist providing the service would be in a position to identify patients in need of additional care and to refer the patient to a dentist for treatment of the condition."

Virginia has made progress and most residents receive more frequent preventive dental care than the national average. But new and more creative initiatives will be needed in the future to improve care for all residents. Proponents also will have to show how new programs or changes in delivering care can be used to save taxpayer dollars, the authors said.