Effects of Medicaid Adult Dental Benefits on Dental Services Utilization and Expenditures

This paper analyzes the role that the Medicaid program plays in affecting dental care use among low income adults and protecting them from significant out-of-pocket (OOP) costs. Using data from the 2000-2015 Medical Expenditure Panel Survey Household Component (MEPS HC) for adults aged 21 to 64, we analyzed outcomes such as having any dental visit, the types of dental services that were performed during the visit(s) such as preventive, diagnostic, restorative, prosthetic, oral surgical, and other services, and total and OOP expenditures. We first compared the outcomes for low-income adults (i.e., those with family income less than 200% of the federal poverty level) to those with higher income. For the low-income group, we then used a multivariate, difference-in-difference model to estimate outcomes for Medicaid compared to low-income adults not on Medicaid and in states where Medicaid provided coverage for non-emergency dental services compared to states that did not. Models controlled for demographic characteristics, state and year fixed effects, and state-specific linear time trends. In 2015, 29 states and the District of Columbia provided coverage of non-emergency dental care services for adults on Medicaid, though the number of states providing coverage varied over time.

We found that lower income adults used fewer dental services of all kinds compared to higher income adults. The biggest difference was for preventive care. Low income adults had 64% fewer preventive visits compared to higher income adults. In contrast, lower income adults actually had higher use of oral surgery. Among low income adults, Medicaid adults in states that did not cover non-emergency dental services used fewer services of all types except oral surgery, compared to low income adults not on Medicaid. In contrast, Medicaid adults used more services than adults not on Medicaid in states that covered non-emergency dental services. We found large differences in all outcomes between Medicaid enrollees in dental coverage states compared to non-coverage states. For example, those in states with coverage were more than twice as likely to have had any preventive services (17.5% versus 6.8%). The out-of-pocket share of dental cost for those with any visit was less than one-third if the state had dental coverage (9.2% versus 34.4%).

Our multivariate results confirmed these findings. Living in a state where Medicaid covered non-emergency dental care for adults increased use of all types of dental services among adults on Medicaid. The biggest effects were for preventive and diagnostic services. Medicaid coverage of adult dental services also increased adherence to recommended service use among groups at high risk of tooth loss, including smokers and diabetics. Coverage also increased per capita dental spending by $73, though reduced per capita OOP spending by $20. The OOP share of spending decreased by nearly 23 percentage points.

In conclusion, we found that income differences in the use of dental care are largest for the use of preventive care. Medicaid coverage of non-emergency dental care increased use of all types of dental care, especially preventive care, therefore alleviating some income differences in the use of preventive dental care.