The Effects of Dental Hygienist Scope of Practice and Autonomy on Dental Care Utilization

Due to the limited supply of health care providers relative to the demand for health care services, many states have increased the practice autonomy of certain types of providers to improve access to care. For example, states have gradually implemented new legislation that enables dental hygienists to perform more tasks without the supervision of dentists as well as establish independent dental hygiene practices. Whether these laws effectively improve access to dental care is an important policy question. Previous research on scope of practice laws for dental hygienists (DH) focused primarily on labor and product market effects. We investigate the effects of dental hygienist scope of practice regulations and autonomy levels on dental care utilization. We also determine whether such laws increase access to care to a greater extent in areas with a shortage of dental care providers.

We use a difference-in-difference approach to estimate the treatment effect of scope of practice laws on the outcomes by exploiting plausibly exogenous timing in the changes of the laws across states. Specifically, we measure the strength the laws by reviewing the relevant state statutes during 2001-2014 and compare changes in the outcomes in states that did not change the level of DH practice autonomy to changes in the outcomes in states that increased DH scope of practice.

Data on dental care utilization for our analysis come from the 2001-2014 Medical Expenditure Panel Survey household dental visit files and full-year consolidated household component files. The variables we construct for dental care visits include total dental visits, preventive care visits and dental treatment visits. We also create indicators variables for specific types of dental services including prophylaxis, applications of sealant, fluoride treatments, X-rays, hygiene screening and assessment, as well as expanded function of placing amalgam restorations. All of our models include a broad set of controls for individual socioeconomic status and health as well as county-level income and educational attainment.

Our results indicate that increasing dental hygienist autonomy is associated with higher utilization of dental care services, with the most pronounced effects for basic preventive care services such as teeth examinations, cleanings, X-rays, and fluoride applications. Importantly, we find that increases in dental care utilization are larger in areas with a shortage of dental care providers. Given that about half of states still significantly limit the autonomy of dental hygienists, the findings in this paper have important policy implications and suggest that expanding the scope of practice of dental hygienists may promote more efficient delivery of dental care.