Project Summary Low rates of dental visits among populations that experience health disparities contribute to the substantial disparities observed in children’s oral health—with worse oral health observed among children in low-income households and Black and Hispanic children. To increase use of preventive oral health services, the US Preventive Services Task Force recommends that medical providers apply fluoride varnish to the teeth of all children aged 5 years and younger. Private health plans and all state Medicaid programs cover this primary pediatric preventive service without cost-sharing. Existing evidence indicates that delivery of fluoride varnish in medical offices increases utilization and reduces decay. Despite these benefits, few children receive it. Our parent grant (NIDCR R01-HS027994-02), funded from 08/14/20 to 05/31/24, aims to identify child, provider, practice, community-, and policy-level factors affecting delivery of fluoride varnish in medical offices in Massachusetts. In response to Notice of Special Interest: Administrative Supplements to Support Research on Preventive Interventions with Populations that Experience Health Disparities (NOT-OD-22-159), we propose to enhance the existing aims of our parent grant by examining racial and ethnic disparities in receipt of fluoride varnish. We will enhance Aim 1 to describe rates of children receiving fluoride varnish in medical settings by race/ethnicity and to determine whether differences by race/ethnicity result from where a child receives care versus children from different racial/ethnic groups receiving different care from the same provider. We will also enhance Aim 3 to examine the association between measures of structural racism (i.e., racialized economic segregation and residential segregation) and rates of children receiving fluoride varnish in medical settings. Our research team is well-suited to complete this work without 12 months because we have existing programs that can be used for the analysis of the Massachusetts Medicaid data (Aim 1) and because the dataset for Aim 3 has already been obtained and cleaned. This proposal will allow our highly successful interdisciplinary team to expand our work by examining if there is inequitable access to a primary preventive service that reduces dental caries across racial/ethnic groups and across communities impacted by racism. These are issues that we would otherwise not have the resources to address. This innovative and timely supplement has the potential to inform where to prioritize additional resources to increase receipt of preventive oral health services.