Root canal myths vs facts — cancer, pain and “dead” teeth explained

Key facts

• Current evidence does not link root canals to cancer
• Modern anaesthesia makes treatment comparable to a filling
• Root-treated teeth can function for many years
• Back teeth usually need a crown after treatment
• Antibiotics alone do not cure an infected tooth

Myth: root canals cause cancer or other diseases

This idea traces back to the “focal infection” theory from the early twentieth century, which suggested that root-treated teeth spread bacteria that cause illness elsewhere in the body. That research had serious flaws and could not be reproduced, and modern studies have not found that root canal treatment causes cancer or systemic disease. Professional dental and medical organisations do not consider root canal treatment a cancer risk. What is known is that untreated dental infection is harmful: it can cause pain, abscesses and, rarely, serious spreading infection. Removing infection through root canal treatment or extraction is the medically sound approach.

Myth: root canal treatment is always very painful

The reputation for pain often comes from the toothache that leads to treatment, not from the treatment itself. A tooth with an inflamed or infected nerve can be extremely painful, and root canal treatment is designed to relieve that pain. With modern local anaesthesia, rotary instruments and careful technique, most patients describe the experience as similar to having a large filling. Occasionally a very inflamed tooth is harder to numb and needs extra anaesthetic. Some tenderness when biting for a few days afterwards is common and usually managed with simple pain relief. Severe, increasing pain or swelling after treatment should be checked.

Myth: a root-treated tooth is “dead” and useless

Removing the nerve means the tooth no longer senses hot and cold, but the tooth is still held in the jaw by living ligament and bone, and it can chew normally. Many root-treated teeth function well for many years. The tooth can become more brittle mainly because of the decay, large fillings and access cavity that preceded treatment, which is why back teeth are usually protected with a crown or onlay. A root-treated tooth can still decay at its edges, so brushing, flossing and check-ups remain important. Keeping your natural tooth also preserves bone and avoids the need to replace it.

Myth: extraction is always better than a root canal

Extraction can seem quicker and simpler, and sometimes it is the right choice, for example when a tooth is badly fractured, has very little structure left or has severe gum disease. However, removing a tooth creates a gap that may lead to neighbouring teeth tipping, the opposing tooth over-erupting and bone loss. Replacing it with an implant or bridge usually involves more time, treatment and cost than saving it. When a tooth is restorable, root canal treatment followed by a proper restoration is often the more conservative option. Your dentist should explain both choices and their long-term consequences honestly.

Other common myths and getting the facts at Manhal

Other myths include that antibiotics alone can cure an infected tooth (they may help spreading infection but do not remove the source inside the tooth), that you do not need treatment once the pain stops (the nerve may have died and infection can continue silently), and that root canals never fail (most succeed, but retreatment is sometimes needed). At Manhal Medical Center in Dubai, Dr. Manhal Helfawee examines the tooth with X-rays and, where useful, CBCT, explains the evidence and options in plain language and provides a written plan. Seek urgent care for facial swelling, fever or difficulty swallowing.

Root canal treatment removes infected or inflamed pulp from inside the tooth, cleans and shapes the canals, and seals them. It relieves toothache and allows you to keep your natural tooth instead of extracting it.

Prepared by the Manhal Medical Center editorial team · Updated: 2026-10-18 · Treating specialist: Dr. Manhal Helfawee

This page is general information and does not replace a consultation. Suitability, risks and results vary between patients.