A persistent and harmful myth about root canals has resurfaced on social media.

An Aug. 1 post on Instagram suggests root canals are linked to breast cancer. The image reads, “97% of our breast cancer patients … had a root canal,” citing Dr. Thomas Rau of the Swiss Biological Medicine Centre.

Rau was affiliated with a debunked movie about root canals, “Root Cause,” which was removed from Netflix in 2019 after backlash from dentists and endodontists.

The Instagram post was flagged as part of Facebook’s efforts to combat false news and misinformation on its News Feed. (Read more about our partnership with Facebook.)

There is no medical evidence that root canals cause cancer, according to the American Association of Endodontists, American Dental Association and American Association for Dental, Oral and Craniofacial Research. The organizations co-signed a letter that was sent to Netflix, Amazon, Apple and Vimeo in 2019, asking that “Root Cause” be removed from their platforms.

“Data showing that ‘97 percent of cancer patients had root canal treatment’ has not been published anywhere,” according to the American Association of Endodontists. “There is no causality between root canals and cancer; just because a person has experienced both doesn’t mean a cause-and-effect relationship exists.”

No studies show that people who get root canals have an increased cancer risk, Eric Jacobs, senior scientific director of epidemiology research at the American Cancer Society, told The Guardian in 2019.

“In fact, research on the link between cancer and endodontic procedures like root canals shows that people who have had these treatments have a lower risk of certain cancers,” the Guardian reported.

The notion that root canals can cause harm is based mostly on discredited dental research from the 1920s.

Our ruling

An Instagram post suggests that root canals are linked to breast cancer.

There is no medical evidence that root canals cause cancer. No studies show that people who get root canals have an increased risk of cancer.

We rate this claim False.