States are required to cover dental services for people with Medicaid under the age of 21, as part of the Early and Periodic Screening, Diagnostic and Treatment (EPSDT) benefit. People under age 21. EPSDT is Medicaid’s comprehensive child health program. The program focuses on prevention, early diagnosis, and treatment of medical conditions.
https://www.hhs.gov/answers/medicare-and-medicaid/does-medicaid-cover-dental-care/index.html

