BACKGROUND:Dentists contribute to the prevailing opioid epidemic in the United States. Concerning the population enrolled in Medicaid, little is known about dentists' opioid prescribing. METHODS:The authors performed a retrospective cohort study of beneficiaries of Medicaid in Washington state with dental claims in 2014 and 2015. The primary outcome was the proportion of dental visits associated with an opioid prescription. The authors categorized visits as invasive or noninvasive by using procedure codes and each beneficiary as being at low or high risk by using his or her prescription history from the prescription drug monitoring program. RESULTS:A total of 126,660 (10.3%) of all dental visits, most of which were invasive (66.9%), among the population enrolled in Medicaid in Washington state was associated with opioid prescriptions. However, noninvasive dental visits and visits for beneficiaries who had prior high-risk prescription use were associated with significantly higher mean days' supply and mean quantity of opioids prescribed. Results from the multivariate logistic regression showed that the probability of having an opioid-associated visit increased by 35.6 percentage points when the procedures were invasive and by 11.1 percentage points when the beneficiary had prior high-risk prescription use. CONCLUSIONS:This baseline of opioid prescribing patterns after dental visits among the population enrolled in Medicaid in Washington state in 2014 and 2015 can inform future studies in which the investigators examine the effect of policies on opioid prescribing patterns and reasons for the variability in the dosage and duration of opioid prescriptions associated with noninvasive visits. PRACTICAL IMPLICATIONS:Dentists must exercise caution when prescribing opioids during invasive visits and to patients with prior high-risk prescription use.