Do Public Health Insurance Expansions Have Teeth? Evidence from Medicaid Adult Dental Benefits

Lipton, Brandy J; Lipton, Brandy J

Provisions of the Affordable Care Act have increased Medicaid enrollment by millions of individuals and increased Medicaid payment rates for targeted services by approximately 73%. We provide evidence on the effect of Medicaid health insurance coverage and provider payment policies in the context of dental care by examining past changes to Medicaid adult dental benefits, which are provided at the state’s option. Most states provide coverage of emergency dental services which include the relief of oral pain and infection, but many states do not cover preventive services such as routine exams and cleanings or restorative services such as fillings and root canals.

To analyze the relationship between dental coverage and dental utilization and health outcomes, we used 2000-2012 data from the National Health Interview Survey (NHIS) and the National Health and Nutrition Examination Survey (NHANES) linked with respondent state of residence and state coverage policies collected through internet search and contact with state health departments. Our main analysis involved a difference-in-difference-in-difference approach, which used variation in the timing of changes in dental coverage policy and a within-state control group of low income adults not enrolled in Medicaid to identify the effect of dental coverage policies on outcomes. Analyses for select years incorporated Medicaid payment rates to dentists to determine whether provider payment generosity affects access to care among beneficiaries with dental coverage. Though provider payment rates do not have a direct effect on Medicaid beneficiaries’ utilization of dental services or dental health, payment generosity may have an indirect effect on these outcomes if providers in states with less generous payment policies decline to participate in Medicaid.

Our findings imply that dental coverage is associated with a nearly 13 percentage point (p<0.01) increase in the likelihood of a yearly dental visit and a reduction of over nine percentage points (p<0.01) in the likelihood of having any untreated dental caries. We also find that for every 10 percentage point increase in the Medicaid to private dental fee ratio, the likelihood of a yearly dental visit increases by about 2.5 percentage points (p<0.05). Not only does our study add to the relatively sparse literature on the effects of Medicaid coverage and payment policies among adults, but we are also among the first to find a significant effect of Medicaid coverage on a clinical health outcome other than mortality.

An estimated 6.1 million individuals gained Medicaid dental insurance as a result of state Medicaid expansions in 2014, making the effects of dental insurance on utilization and health outcomes among the Medicaid population of interest. A simple back-of-the-envelope calculation using our results implies that the Medicaid expansions could lead to an additional 785,680 (6.1 million x 0.1288) annual dental visits based on the increase in enrollment as of August 2014.

Association for Public Policy Analysis & Management

Panel Paper: Do Public Health Insurance Expansions Have Teeth? Evidence from Medicaid Adult Dental Benefits