PROJECT SUMMARY/ABSTRACT Low-income adults in the United States have historically had worse dental health and overall health status than higher income individuals and less access to dental and medical services. Oral health is a key component of overall health and wellbeing. However, the relationships between oral health and overall health are bi-directional and subject to several confounders. Given these complex relationships, there is a need for evidence examining the causal impacts of changes in access to dental services on overall health status. We will contribute substantially to filling this knowledge gap by leveraging recent exogenous changes in dental coverage and dental services use due to the Affordable Care Act (ACA) Medicaid expansions as a natural experiment to study effects of dental services use on overall health status. As of 2019, 33 states expanded Medicaid eligibility to all non-elderly adults below 138% of the federal poverty level. However, Medicaid dental coverage for adults is optional for states, and as a result, there is significant variation in dental coverage across states and over time. This variation provides a unique opportunity to understand the spillover effects of dental coverage and services use on overall health status. The ACA Medicaid expansions with dental benefits have increased dental visits and use of preventive and treatment dental services but effects differed by generosity of dental benefits. That evidence demonstrates that the Medicaid expansions with their variation in dental benefits provide a unique opportunity to understand connections between access to dental services and overall health status. Taking advantage of a natural experiment and existing data from two nationally representative surveys, we will provide the first evidence on effects of the recent Medicaid expansions with dental benefits for low-income adults on their overall health status over 7 years from the first expansions. We will examine heterogeneity in effects by state generosity of dental coverage, dentist supply, and demographic variables associated with l health status, oral health and dental services use. The evidence from the study is highly relevant for accurate evaluations of the effectiveness and cost-benefit of oral health programs and policies by accounting for spillover benefits to overall health. The evidence will also be useful for Medicaid policies both nationally and for states. Findings will also inform discussions among policymakers and stakeholders about offering dental coverage in Medicare for older adults and in employer-sponsored or independently purchased plans. The study will also motivate larger scale studies using other data sources such as claims data to assess changes in dental and medical care use at the individual-level using quasi-experimental designs.