MODERN ROOT CANALS are safe, effective, and often the best option for saving a damaged or infected tooth. But the road to today’s trusted endodontic care was not a straight one. In fact, the early 20th century nearly wiped out the entire field of endodontics — not because the treatments didn’t work, but because of one wildly influential, poorly supported idea that spiraled out of control.
This is the story of how root canals were almost abandoned altogether, and how decades of misinformation led to the unnecessary extraction of millions of healthy teeth.
The Rise of the Focal Infection Theory
In the early 1900s, E.C. Rosenow and Weston Price published a series of studies claiming that root canal-treated teeth could cause systemic illness. This “focal infection theory” proposed that bacteria trapped inside a root canal could travel to other parts of the body and cause serious conditions such as arthritis, kidney disease, or heart problems.
Rosenow and Price’s claims were based on questionable experiments. In some studies, Price extracted root canal-treated teeth from patients with chronic illnesses and implanted them under the skin of rabbits. When the rabbits later became ill or died, Price concluded that the teeth must have caused systemic disease in humans.
The problem? These studies lacked proper controls, scientific rigor, and an understanding of microbiology. But that didn’t stop the theory from spreading like wildfire.
Tooth Extraction Becomes the “Safe” Choice
By the 1920s and 1930s, the focal infection theory had become widely accepted among medical and dental professionals. Root canal treatment, once a promising method of saving teeth, was now seen as dangerous. Physicians and dentists began recommending the extraction of all root canal-treated teeth (and often, all teeth in general) as a preventative measure against disease.
The consequences were staggering. Healthy teeth were pulled by the millions in the name of “safety.” Entire mouths were extracted preemptively in children and adults. People underwent full-mouth extractions and were fitted with dentures to supposedly prevent future health problems.
During this time, endodontics was considered fringe, and those who advocated for saving teeth were often dismissed or ridiculed. The field teetered on the edge of extinction, and some dentists even wanted it criminalized and penalized with hard labor.
Fighting Back With Evidence
It took decades for science to catch up with the myths. As research methods improved in the mid-20th century, better-designed studies found no link between root canal-treated teeth and systemic disease. Dentists and researchers began to challenge the focal infection theory with real evidence, and gradually, the pendulum began to swing back.
In 1943, the American Association of Endodontists (AAE) was founded to support the specialty and re-establish trust in the science of root canal treatment. Over time, endodontists have proven not only that saving teeth is safe, but also that it is often the best course of action for long-term oral and overall health.
From Pseudoscience to Modern Precision
Today, endodontists use cutting-edge tools like operating microscopes, digital imaging, and advanced irrigation systems to treat teeth with incredible accuracy. Root canal therapy is one of the most successful procedures in dentistry, thanks to the persistence of specialists who refused to let bad science win.
A Victory for Science — and Your Smile
The history of endodontics is more than just drills and fillings. It’s a cautionary tale about the power of misinformation and a celebration of the dedication it took to restore a misunderstood field. So the next time you hear someone question root canals, remember: today’s endodontists are backed by science, not superstition.
