A new study has shown that patients undergoing wisdom tooth surgery receive far more painkillers than necessary, with more than half typically going unused.

The findings came from researchers at the University of Pennsylvania's Perelman School of Medicine and School of Dental Medicine and were published last month in the journal Drug and Alcohol Dependence.

The study followed 79 patients who underwent wisdom tooth removal and tracked how much medication they both received and consumed. Ninety-four percent of the patients received an opioid prescription post-surgery to help manage pain symptoms, while about 80% also received a prescription-strength antibiotic and/or a prescription-strength anti-inflammatory drug.

Their research showed that most of the patients no longer needed painkillers after a few days, but received enough medication to last several weeks. Study co-author Dr. Elliot Hersh noted, “Results of our study show within five days of surgery, most patients are experiencing relatively little pain, and yet, most still had well over half of their opioid prescription left.”

On average, patients without complications after surgery received 28 pills, but still had 15 pills remaining three weeks after surgery.

"When translated to the broad U.S. population, our findings suggest that more than 100 million opioid pills prescribed to patients following surgical removal of impacted wisdom teeth are not used, leaving the door open for possible abuse or misuse by patients, or their friends or family," said study author Dr. Brandon Maughan.

But while the findings raise obvious concerns about where these unused medications go and who may end up with them, the study also noted that informing patients about drug disposal programs led to a 22% increase in properly disposing of any unused substances.

“All prescribers—including physicians, oral surgeons and dental clinicians—have a responsibility to limit opioid exposure, to explain the risks of opioid misuse, and educate patients on proper drug disposal," said Maughan.

However, this issue expands well beyond wisdom tooth surgery. Despite new guidelines from the Centers for Disease Control and Prevention that call for limits on opioids prescriptions, surgeons aren’t adhering to them.

A recent study from doctors at the Dartmouth Hitchcock Medical Center in New Hampshire showed that out of the 642 patients they followed post-surgery, more than 90% were prescribed opioids. In follow-up interviews with about 20% of the patients, they admitted to only taking 29% of the medication prescribed to them.