Patients tell me things in my chair that they have read online or heard from a friend, a cousin or a WhatsApp group. Some of it is harmless. Some of it keeps people away from treatment they really need. So let me go through the five myths I hear the most, and tell you honestly what is true and what is not.

Myth 1: Root Canals Make You Sick

This is the big one. People tell me a root canal will cause illness in the rest of the body, even serious illness. I understand why it scares people, because it is a very old idea. Almost a hundred years ago, a dentist named Weston Price said that infected teeth caused many diseases. Better studies done afterwards did not support his theory. Today, dental and root canal specialist associations say there is no scientific evidence that a root canal makes you ill. Research has also not shown that having one changes your cancer risk.

Here is what actually causes harm. A tooth with a dead or infected nerve that is left alone. That infection can damage the bone around the tooth and spread to other areas. The root canal is the treatment that cleans out that infection so you can keep your own tooth. It is not the cause of the problem.

Myth 2: Silver Fillings Are Slowly Poisoning You

Let me clear up one thing first. The mercury people worry about is not in a root canal. It is in old style silver fillings, which are called amalgam fillings. About half of an amalgam filling is mercury, mixed with silver, tin and copper.

Do these fillings release a tiny amount of mercury vapour? Yes, they do. The question is whether it is enough to harm you. The American health authority, the FDA, says that most evidence shows the mercury from amalgam fillings does not cause health problems in the general population. It also says that there are things we are still learning.

There are some people who should be more careful. These include pregnant women and women planning a pregnancy, breastfeeding mothers, young children, people with certain nerve or kidney conditions, and anyone who is allergic to the metals in the filling. If that is you, please tell me, and we will talk about other filling materials.

And here is the part people do not expect. If your old silver fillings are in good condition, taking them out is usually not recommended. Drilling them out removes healthy tooth and briefly increases your mercury exposure. Please do not rush to have good fillings removed because of something you saw online.

Myth 3: Fluoride Is Poison

Fluoride is probably the most argued about topic in dentistry right now, so I want to be careful and honest with you. Fluoride helps to strengthen enamel and protect teeth against cavities. At the recommended amounts, major dental associations consider it safe and effective. But it is true that too much is not good for children. Too much while the teeth are forming can cause white or brown marks on the teeth, which is called fluorosis.

You may have also heard about a large United States government review in 2024. It found that fluoride in drinking water at levels of 1.5 mg per litre or higher, which is more than twice the recommended level of 0.7, was linked to lower IQ in children. What it did not do is show that the much lower levels used in toothpaste and in fluoridated water cause that problem. The American Dental Association said it found nothing in that report that required a change in current practice.

So what do I tell my patients? Use fluoride toothpaste, and use it the right way. For small children, that means a tiny, pea sized amount, and an adult watching to make sure they spit it out and do not swallow it. If you are worried about the fluoride in your area, speak to me and we will work out what makes sense for you and your family.

Myth 4: If It Does Not Hurt, Nothing Is Wrong

I wish this were true. Teeth and gums are very good at hiding problems. A cavity can grow for months without pain. Gum disease is usually painless until it is quite far along. By the time a tooth hurts, the problem has often reached the nerve. This is why check-ups matter even when everything feels fine. I can see and find things long before you ever feel them, and early treatment is simpler, cheaper and more comfortable for you.

Myth 5: Dental X-Rays Are Dangerous

Many patients ask if they can skip the X-ray, especially when they are worried about radiation. I understand the concern, so here are the facts. We are all exposed to natural background radiation every day, from the ground, the air and the sun. Dental X-rays add a very small amount to that. A set of four bitewing X-rays taken with digital or faster film is roughly the same as somewhere between less than a day and about five days of normal background radiation. A single panoramic X-ray is around one to two days.

I only take an X-ray when I need one, because without it I cannot see between your teeth, under old fillings or around the roots. Skipping the X-ray does not make a problem go away. It only means I cannot see it. If you are pregnant, please tell me before we take any X-rays.

The Bottom Line

Not every myth comes from nowhere. Some of them started with a real concern, like too much fluoride for small children, or mercury in certain people. The trouble comes when a small, specific concern becomes a rule for everyone, and people avoid treatment because of it. If you have heard something about your teeth that worries you, please bring it to me. I will never laugh at a question, and I will always tell you what the evidence says, even when the answer is that we do not know everything yet.