Dental hygiene scope of practice regulation significantly impacts oral health outcomes in state populations. A numerical scope of practice scale for dental hygienists, called the Dental Hygiene Professional Practice Index (DHPPI), scored numerous variables relevant to dental hygiene practice, including the regulatory environment, tasks permitted, levels of required supervision by setting, and reimbursement for services.

This article describes the comparison of state DHPPI scores in each of 3 years (2001, 2014, and 2016) to evaluate the impact of scope of practice expansions on oral health outcomes.