IMPORTANCE There is a recommendation for children to have a dental home by 6 months of age, but there is limited evidence supporting the effectiveness of early preventive dental care or whether primary care providers (PCPs) can deliver it. OBJECTIVE To investigate the effectiveness of preventive dental care in reducing caries-related treatment visits among Medicaid enrollees. DESIGN, SETTING, AND PARTICIPANTS High-dimensional propensity scoreswere used to address selection bias for a retrospective cohort study of children continuously enrolled in coverage from the Alabama Medicaid Agency from birth between 2008 and 2012, adjusting for demographics, access to care, and general health service use. EXPOSURES Children receiving preventive dental care prior to age 2 years from PCPs or dentists vs no preventive dental care. MAIN OUTCOME AND MEASURES Two-part models estimated caries-related treatment and expenditures. RESULTS Among 19 658 eligible children, 25.8% (n = 3658) received early preventive dental care, of whom 44%were black, 37.6%were white, and 16.3%were Hispanic. Compared with matched children without early preventive dental care, children with dentist-delivered preventive dental care more frequently had a subsequent caries-related treatment (20.6%vs 11.3%, P < .001), higher rate of visits (0.29 vs 0.15 per child-year, P < .001), and greater dental expenditures ($168 vs $87 per year, P < .001). Dentist-delivered preventive dental care was associated with an increase in the expected number of caries-related treatment visits by 0.14 per child per year (95%CI, 0.11-0.16) and caries-related treatment expenditures by $40.77 per child per year (95%CI, $30.48-$51.07). Primary care provider-delivered preventive dental care did not significantly affect caries-related treatment use or expenditures. CONCLUSIONS AND RELEVANCE Children with early preventive care visits from dentists were more likely to have subsequent dental care, including caries-related treatment, and greater expenditures than children without preventive dental care. There was no association with subsequent caries-related treatment and preventive dental care from PCPs.We observed no evidence of a benefit of early preventive dental care, regardless of the provider. Additional research beyond administrative data may be necessary to elucidate any benefits of early preventive dental care.