Introduction: Dentists prescribe 1 in 10 opioid prescriptions in the U.S. When opioids are necessary, national guidelines recommend the prescription of low-dose opioids for a short duration. This study assesses the appropriate prescribing of opioids by dentists before guideline implementation. Methods: The authors performed a cross-sectional analysis of a population-based sample of 542,958 U.S. commercial dental patient visits between 2011 and 2015 within the Truven Health MarketScan Research Databases (data analysis October 2018-April 2019). Patients with recent hospitalization, active cancer treatment, or chronic pain conditions were excluded. Prescription opioids were ascertained using pharmacy claims data with standardized morphine equivalents and recorded days' supply. Appropriate prescribing was determined from the 2016 Centers for Disease Control and Prevention guidelines for pain management based on a recommended 3 days' supply of opioid medication and anticipated post-procedural pain. Results: Twenty-nine percent of prescribed opioids exceeded the recommended morphine equivalents for appropriate management of acute pain. Approximately half (53%) exceeded the recommended days' supply. Patients aged 18−34 years, men, patients residing in the Southern U.S., and those receiving oxycodone were most likely to have opioids prescribed inappropriately. The proportion of opioids that exceed the recommended morphine equivalents increased over the study period, whereas opioids exceeding the recommended days' supply remained unchanged. Conclusions: Between 1 in 4 and 1 in 2 opioids prescribed to adult dental patients are overprescribed. Judicious opioid-prescribing interventions should be tailored to oral health conditions and dentists.