Objectives: As emergency department (ED) visits for non-traumatic dental complaints continue to rise in the United States (U.S.), some states are implementing initiatives to expand access to the oral health workforce. This study examines the associations between the 2014 Dental Hygiene Professional Practice Index (DHPPI) and preventable dental ED visits. Methods: In 2020, we used ED data from 10 U.S. states and ordinary least squares models to examine the relationship between the states’ DHPPI scores and preventable dental ED use. We stratified regressions by age to examine this relationship across different age cohorts and introduced interaction terms to assess the same relationship among rural and urban residents. Results: On average, 23.8% of all non-traumatic dental ED visits were identified as preventable. Controlling for other factors, a one-point increase in DHPPI scores was associated with a decrease of 0.01 (95% CI −0.03, −0.02) preventable dental ED visits per 1000 county population in each year-quarter. In the age-stratified models, the strength of the association between DHPPI scores and preventable dental ED visits was higher in the 20 to 34 (−0.03, 95% CI −0.04, −0.02), and the 35 to 50 age cohorts (−0.17, 95% CI −0.00, −0.00). U.S. states with DHPPI scores below 60 saw significantly higher preventable dental ED visits among rural residents. Conclusions: This study demonstrates that stringent state policies regarding the dental hygienist workforce are associated with higher preventable dental ED visits in the U.S. Policy makers and stake holders must address the scope of practice policies to alleviate the burden of access to oral healthcare.