The Impact of Kentucky's Medicaid Expansion Under the Affordable Care Act on Dental Care Visits

Abstract

Background. Lack of health insurance, cost of dental care services, and shortage of dental workforce are leading barriers to dental care access. Low-income adults and those who reside in areas with low dentist supply are less likely to visits a dental office than their counterparts. Studies have reported that dental visits increased among low-income adults in states that expanded Medicaid under the Affordable Care Act (ACA) and have an adequate number of dentists. However, the impact of Medicaid expansion on incomebased disparities and urban-rural disparities in dental care visits is unclear. Objectives. The aim of this study is to examine the impact of Medicaid expansion under the ACA in Kentucky on dental visits among non-elderly adults. Also, to assess how the impact of Medicaid expansion on dental visits differs by the county-level rate of dentists. Methods. This study includes three research papers. Paper 1 assesses the impact of Medicaid expansion by household income levels (Low, Middle, versus High). Paper 2 examines the impact of Medicaid expansion by pre-ACA uninsured rates at the ZIP code level (High, Middle, versus Low). Paper 3 examines the impact of Medicaid expansion by the county of residence (Rural, Appalachian, versus Urban). Difference-in-differences regression models were used in the three papers to compare changes in dental visits from pre-ACA to post-ACA among treatment and control groups. An event study approach was also used to model year-to-year changes in the levels of dental visits across treatment and control groups. Results. By 2018, dental care visits, within the past year, among low-income adults residing in counties with a high rate of dentists increased by 11.5 percentage points (19 percent, 95% CI: 2.0 - 21.0). Also, dental visits among individuals residing in ZIP codes with high uninsured rates, in counties with a high supply of dentists, increased by 11.6 percentage points (95% CI: 2.5 – 20.8, p<0.01). The findings show no statistically significant increases in dental visits among rural and Appalachian residents. Conclusion. Expanding Medicaid under the ACA in Kentucky helped in narrowing the gap in dental visits between low- and high-income adults. However, there was no improvement in dental visits among individuals residing in counties with low dentist supply. The gap in dental visits between urban and rural residents is still unaddressed. This study highlights the importance of Medicaid expansion and having an adequate supply of dentists in improving access to dental care among low-income adults. KEYWORDS: Medicaid expansion, dental care, disparities, rural, health coverage, dentist supply.