Dental Therapy Authorization and Oral Health Access: Evidence from Staggered State Adoption

Abstract

Dental therapists are mid-level providers authorized to perform preventive and basic restorative dental procedures. Since 2009, thirteen U.S. states have authorized dental therapy practice, motivated by concerns about dental access in underserved communities. This paper provides quasi-experimental evidence on the population-level effects of dental therapy authorization on oral health access. Using a difference-in-differences design with staggered adoption and Callaway-Sant'Anna estimators, I compare dental visit rates in nine authorizing states with identified treatment effects to not-yet-treated states using BRFSS data from 2012–2020. Contrary to policy expectations, I find that dental therapy authorization is associated with a 1.3 percentage point decrease in the proportion of adults visiting a dentist (SE = 0.6 pp, $p = 0.041$). Pre-trends tests do not reject the parallel trends assumption ($p = 0.12$). This counterintuitive finding may reflect reverse causation (states with declining dental access are more likely to adopt dental therapy) or compositional changes in the dental workforce. The results caution against expecting population-level improvements from dental therapy authorization alone and highlight the importance of understanding why states adopt such policies. \vspace{1em} JEL Codes: I11, I18, J44 Keywords: Dental therapy, oral health, access to care, difference-in-differences, healthcare workforce