Dentists are dropping out of Minnesota's Medicaid program because of lagging reimbursement rates, creating hurdles for low-income families who seek dental care, the state's legislative auditor has concluded.

Dentists participating in the state's Medicaid program — Medical Assistance — are reimbursed at some of the lowest rates in the nation, and increased costs of treatment are compelling some to opt out, the report says.

"Folks do have access now, but increasing the rates would help more," said Scott Leitz, assistant commissioner at the Minnesota Department of Human Services. Leitz said he concurred with the report's recommendations and said his agency included dental providers in a proposed 5 percent rate increase in Gov. Mark Dayton's biennial budget.

About 65 percent of licensed Minnesota dentists served at least one Medical Assistance patient between 2006 and 2011, the report said. But 24 percent of dentists surveyed said they stopped serving the program's patients after 2010, primarily due to low payment rates.

Medical Assistance is Minnesota's largest publicly funded health care program, providing coverage for 910,000 people in 2011. But dental services, the report said, are only 3 percent of the program's expenditures.

The program's rates for dentists were lower in 2012 than in 2000 and below that of most other states; Minnesota ranked in the lower one-third nationally. Additionally, the report said state dental reimbursement rates are based on adjustments from 1989 and don't reflect the current costs of care.

A recent report from the Minnesota Department of Health said about 55 percent of third-graders surveyed in 2010 had experienced cavities — a figure that caused concern among public health authorities — and that children from poor families in particular struggle to find dental care. The report said lack of preventive dental care resulted in $148 million in emergency room charges for untreated dental problems.

"Reimbursements are one factor," said Michael Scandrett, an attorney and health care consultant at Halleland Habicht in Minneapolis. "But even with higher reimbursements, it's a complicated process."

Scandrett said that he wasn't certain a 5 percent increase would make any more than a "small dent" but that "it's a step in the right direction."

The report also said that Minnesota's many payment methods for dental providers are "poorly coordinated and inconsistently applied," adding that fee-for-service dental rates should increase, with attention given to patients with special needs.

While managed-care organizations contracting with Medical Assistance often pay dentists more than the state's base rates, "the differences are sometimes small," the report said.

The report recommended that the Legislature and the Department of Human Services revise pay rates for Medical Assistance dental providers and adopt a different payment structure for patients with special needs.

Jeff Hargarten is a University of Minnesota student reporter on assignment for the Star Tribune.