Despite the importance of Medicaid for the oral health of low-income adults, the extent to which Medicaid dental policy variation influences outcomes is unknown. This study aims to review the evidence evaluating adult Medicaid dental policies to synthesize conclusions and motivate future research.

A comprehensive search of academic literature published in English between 1991 and 2020 was conducted to identify studies which evaluated an adult Medicaid dental policy for its effect on outcomes. Studies strictly involving children, policies not related to adult Medicaid dental coverage, and non-evaluation studies were excluded. The data analysis identified the policies, outcomes, methods, populations, and conclusions of the included studies.

Among the 2731 unique articles extracted, 53 met the inclusion criteria. 36 studies evaluated the effect of expanding Medicaid dental coverage, which was found to consistently increase dental service visits (21 studies) and reduce unmet dental needs (4 studies). Provider density, reimbursement rates, and level of benefits appear to influence the effect of expanding Medicaid dental coverage. The evidence for changing Medicaid benefits and reimbursement rates were mixed for its impact on provider participation and emergency dental services. Few studies examined how adult Medicaid dental policies impact health outcomes.

Most of the recent research has focused on evaluating the effect of expanding or reducing Medicaid dental coverage on dental service utilization. Future research investigating the impact of adult Medicaid dental policies on clinical, health, and wellness outcomes remains warranted.

Low-income adults are responsive to Medicaid dental policy changes and utilize more care with more generous coverage. Less is known about how these policies influence health.