Root Canals and Cancer

There has been a lot of speculation recently about an article that has been making the rounds on social media websites from “” regarding a connection between root canal therapy and terminal cancer.  As both doctors and scientists, it is important that we here at Dental Health set the record straight. The first thing we want to address is plainly this: There are HUNDREDS of websites out there with similar, oddly-spelled web domains at any given time that spew “information” that at best is controversial and at worst junk science — meaning not conducted using the scientific method. You may remember those lab reports from high school or college science, in which you had to formulate a question, construct your experiment, gather data, etc. No? well luckily we have a nice brightly colored flow chart that will help jog your memory!

While this is a very, very simplified chart of the research steps needed to prove any scientific hypotheses, it speaks volumes to the problems with many of the “conspiracy theory”-type articles found online.

The problem specifically with the article lies within the green “test with an experiment” section of our flow chart. The author writes that “97% of terminal cancer patients” have had root canals, and then goes on to write that there are approximately “25 million root canals” performed every year. The problem with drawing such a direct correlation between cancer and root canals is a common concept in research that has caused many, many research experiments to fail: variables and controls.

-A variable is simply known as an “unknown” factor in research. It is often the focus of research to prove that a specific variable can cause a condition. However, in order to do that one must be able to manipulate the variable to determine if changes in one variable cause changes in another variable. There are many different types of variables, and because of this, experiments have controls.

-Controls or a control group in a scientific experiment is a group separated from the rest of the experiment where the variable being tested cannot influence the results. This isolates the variable’s effects on the experiment and can help rule out alternative explanations of the experimental results.

Simply put, it means this:

If we were to draw a diagram of people that have had root canals and people that simply exist in the US, there would admittedly be a large percentage of people in the US that have had root canals. To draw out the inconsistencies in their research technique, I will compare the number of people who have had root canals as being similar to the number of people that are  nearsighted, or wear glasses, as an example.

So, if such a large percentage of people that exist in the US are nearsighted, it stands to measure that the population of people that have or have had cancer is a much, much smaller subsection of the US population. Therefore, when you look at the percentage of people that have had cancer AND are nearsighted, you may be able to say 97% of those people that have had cancer are also nearsighted!!

In this way, you have correlated a direct, unscientific connection between terminal cancer and nearsightedness. However, you have not taken into consideration THOUSANDS of  variables, or unknowns, that contribute to cancer, using control groups that test or isolate variables out of our conclusions.

In short, it is false and unscientific to make a claim that an arbitrary percentage of terminal cancer patients are nearsighted, and in a similar fashion, it is equally so to claim an arbitrary percentage of terminal cancer patients have had root canals.

Another very important part of the scientific method are the sources. It is integral to the scientific method to cite all sources of your research and information, and no, sources cannot be wikipedia or any non-scholarly source. This author has cited absolutely no sources, scholarly or otherwise, meaning that none of the statistical data may even exist.

I may also add that there is a disclaimer on the bottom of this article stating that no one from this website is certified to give medical advice, and that before doing anything, you should consult a medical professional, which doesn’t do much for their credibility.

Additionally, every time he cites a study, he cites correlation, not causation, meaning that root canals correlate to higher levels of disease, but that’s not saying that they cause disease. Again, this goes back to what we had mentioned before about variables and controls. It could similarly be argued that, say, eating a rich dessert could correlate to higher levels of heart disease, considering that it has higher levels of fat and cholesterol, but again, can’t say that eating a rich dessert actually causes heart disease.

Furthermore, he alleges that each of the 25 million root canals that are performed every year in this country are “silent incubators for highly toxic anaerobic bacteria” that “make their way into your bloodstream to cause a number of serious medical conditions” and imply that various types of cancer are one of these side effects. There lies a huge falsity: If a root canal has been completed and has (for whatever reason) NOT created a sterile environment in which bacterial colonization has been limited, that tooth will eventually reappear with infection. It can take time for the infection to reappear, however if infection reappears, it will be visible in radiographs and often is clinically swollen or painful. In short, it is very, very rare that a large percentage of bacteria and a re-infected and failing root canal go undetected for “years” as the article claims.

He  implies that the entire scientific/dental community is trying to keep this “truth” hidden, but doesn’t ever give proof that the American Dental Association has hidden it, or why they would do so and put many lives at risk. Additionally, we did some google-ing and could not find many of the so-called “dentists” they cite in their statistics. Here at Dental Health, we take the oath we took as medical professionals very seriously, and “do no harm” is one of them.

Our dentists at Dental Health are very open to alternative medicine, and welcome new research and technique with open arms. Learning and growth are important aspects of providing a high standard of care in dentistry. However, we do advise you to use your better judgement about where you receive your information and who you trust and we implore you to look for the use of proper scientific methods or research, scholarly sources and well-known websites prior to making decisions that could adversely affect your dental and overall health!

Dr. Pourkay practices dentistry in our Boulder, CO office.

Dr. Sara Pourkay, Dental Health of Boulder


  1. Thank you so much for this article. I will admit that I was scared out of my mind when I first began searching the internet about root canals. I had to have an emergency root canal on Monday, most likely because of a trauma to the tooth three years ago. (Bike accident. Lots of blood, very messy.) I didn’t know anything about them before I had to have one, and what I was finding out was SO frightening. I’m prone to panic attacks and nearly had one reading through all those websites.

    However, my logical side just took ahold of me and said, “Well, if this is true, certainly there is at least one scientific study performed in the last 10/20 years that concurs with all of these websites.” Lo and behold, a quick Google of “scientific evidence that root canals cause cancer” turned up absolutely no scientific proof. You’ve just made me feel so much better. Again, thank you. I just needed someone else (preferably a dentist!) to say it.

  2. Could you post a link to a couple of peer-reviewed papers on this?

  3. Gordon Leon says

    Do you know the percentage of people that have had root canals?

  4. Thank you for publishing. This was excellent.

  5. Dr. Pourkay,

    I would encourage you to read ‘Root canal cover up’ by George E. Meinig, DDS, FACD . It summarizes all the scientific findings of Dr. Weston Price (the inventor of root canals) related to root canals and its relation to all sort of degenerative diseases.

    Then, review the text above your picture, I guarantee it you will think different.

    Good luck!… for the good of your patients.

    Warmest regards,


  6. Thank you for your article. I believe that science built upon true information and proper assessment of the information is there to help us all. Your article describes the same concern I’ve had since reading and hearing about this claim regarding root canal therapy.
    Thanks for the time you’ve taken to respond intelligently to misinformation being disseminated as factual.