This article examines the effect of Medicaid adult dental coverage on use of dental care and dental health outcomes using state-level variation in dental coverage during 2000-2012. Our findings imply that dental coverage is associated with an increase in the likelihood of a recent dental visit, with the size of the effect increasing with Medicaid payment rates to dentists, and a reduction in the likelihood of untreated dental caries. We are among the first to detect an effect of Medicaid coverage on a clinical health outcome other than mortality. These findings may have implications for states expanding Medicaid coverage to adults with incomes of up to 138% of the federal poverty threshold under the Affordable Care Act as most of these states offer an adult dental benefit.

Prior to the Affordable Care Act, one in three young adults aged 19 to 25 years were uninsured, with substantial racial/ethnic disparities in coverage. We analyzed the separate and cumulative changes in racial/ethnic disparities in coverage and access to care among young adults after implementation of the Affordable Care Act's 2010 dependent coverage provision and 2014 Medicaid and Marketplace expansions. We find that the dependent coverage provision was associated with similar gains across racial/ethnic groups, but the 2014 expansion was associated with larger gains in coverage among Hispanics and Blacks relative to Whites. After the 2014 expansion, coverage increased by 11.0 and 10.1 percentage points among Hispanics and Blacks, respectively, compared with a 5.6 percentage point increase among Whites. The percentage with a usual source of care and a recent doctor's visit also increased more for Blacks relative to Whites. Increases in coverage were larger in Medicaid expansion compared with nonexpansion states for most racial/ethnic groups.

Previous research has demonstrated large gains in insurance coverage associated with the Affordable Care Act's (ACA's) Medicaid expansion in 2014. We used detailed federal survey data through 2015 to analyze more recent changes in coverage for low-income adults after the expansion. We found that the uninsurance rate fell in both expansion and nonexpansion states but that it fell significantly more in expansion states. By 2015 the post-ACA uninsurance rate for low-income adults had fallen by 7.5 percentage points more in expansion than in nonexpansion states, a difference that was similar (about 6.8 percentage points) in adjusted regression models. Private coverage increased in nonexpansion states, but significantly less than Medicaid coverage increased in expansion states. Rates of private coverage did not appear to decline in expansion states. Finally, Medicaid expansion was associated with significantly improved quality of health coverage, as reported by low-income adults.

Affordable Care Act provisions implemented in 2010 required insurance plans to offer dependent coverage to people ages 19-25 and to provide targeted preventive services with zero cost sharing. These provisions both increased the percentage of young adults with any source of health insurance coverage and improved the generosity of coverage. We examined how these provisions affected use of the human papillomavirus (HPV) vaccine, which is among the most expensive of recommended vaccines, among young adult women. Using 2008-12 data from the National Health Interview Survey, we estimated that the 2010 policy implementation increased the likelihood of HPV vaccine initiation and completion by 7.7 and 5.8 percentage points, respectively, for women ages 19-25 relative to a control group of women age 18 or 26. These estimates translate to approximately 1.1 million young women initiating and 854,000 young women completing the vaccine series.

Affordable Care Act (ACA) provisions implemented in 2014 provide a valuable case study regarding the merits of using public versus subsidized private insurance to help low-income people obtain and finance health care. In particular, nonelderly adults with incomes of 100-138 percent of the federal poverty level gained Medicaid eligibility if they lived in states that implemented the ACA's Medicaid expansion, whereas those in nonexpansion states became eligible for subsidized Marketplace coverage. Using data for 2008-15 from the National Health Interview Survey, we found that as of 2015, adults with family incomes in this range had experienced large declines in uninsurance rates in both expansion and nonexpansion states (the adjusted declines were 22 percentage points and 18 percentage points, respectively). Adults in expansion and nonexpansion states also experienced similar increases in having a usual source of care and primary care visits, and similar reductions in delayed receipt of medical care due to cost. There were, however, important differences: Adults in expansion states experienced larger reductions in out-of-pocket spending but also faced greater difficulty accessing physician care relative to adults in nonexpansion states.