Medicaid was expanded to millions of individuals under the Affordable Care Act, but many states do not provide dental coverage for adults under their Medicaid programs. In the absence of dental coverage, patients may resort to costly emergency department (ED) visits for dental conditions. Medicaid coverage of dental benefits could help ease the burden on the ED, but ED use for dental conditions might remain a problem in areas with a scarcity of dentists. We examined county-level rates of ED visits for nontraumatic dental conditions in twenty-nine states in 2010 in relation to dental provider density and Medicaid coverage of nonemergency dental services. Higher density of dental providers was associated with lower rates of dental ED visits by patients with Medicaid in rural counties but not in urban counties, where most dental ED visits occurred. County-level Medicaid-funded dental ED visit rates were lower in states where Medicaid covered nonemergency dental services than in other states, although this difference was not significant after other factors were adjusted for. Providing dental coverage alone might not reduce Medicaid-funded dental ED visits if patients do not have access to dental providers.