7 Signs You May Need a Root Canal

Published May 25, 2026
4 min read
Cornwall Dental Arts team
Treatments

Few phrases make Cornwall patients more nervous than “root canal” — and few dental procedures are more misunderstood. A root canal doesn’t cause the pain people associate with it; it relieves pain that’s already there. The tricky part is knowing when a sore tooth is just sensitive and when the nerve inside it is in real trouble.

The pulp — the soft tissue of nerves and blood vessels inside each tooth — can become inflamed or infected because of deep decay, a crack, a large or repeated filling, or trauma. Once that happens, the problem doesn’t heal on its own. Here are seven signs it may be time to have a tooth assessed for root canal treatment.

1. Tooth pain that lingers or keeps coming back

Ordinary sensitivity comes and goes in seconds. Pulp inflammation is different: the ache is deeper, lasts longer, and often returns without an obvious trigger. Pain that wakes you at night, throbs with your heartbeat, or gets worse when you lie down is a classic warning sign that the nerve inside the tooth is involved.

2. Lingering sensitivity to hot or cold

A brief zing from ice water can be normal. But if a hot coffee or cold drink causes pain that hangs around for 30 seconds or more after the temperature is gone, the pulp may be inflamed beyond the point of recovery. Heat sensitivity in particular — a tooth that aches with warm foods — often points toward a dying nerve.

3. Pain when you bite or chew

If pressing on one specific tooth hurts — chewing on that side, tapping the tooth, even closing your teeth together — infection may be spreading from the pulp into the ligament and bone around the root. Many patients start unconsciously chewing on the other side of their mouth long before they book an appointment.

4. A darkening or greying tooth

When the pulp is injured or dies, the tooth can slowly change colour — turning grey, brown or darker than its neighbours. This is common after an old injury (a sports knock or fall, sometimes years earlier) and can happen even without pain. A single darkening tooth should be examined.

5. Swollen or tender gums near one tooth

Localized gum swelling or tenderness around a single tooth — rather than along the whole gumline — suggests infection at the root tip rather than general gum problems. If you’re not sure which issue you’re dealing with, our page on gum disease treatment explains how gum-related symptoms differ.

6. A pimple-like bump on the gums

A small, recurring bump on the gum near a tooth (dentists call it a fistula) is a drainage point for infection inside the bone. It may pop, leak an unpleasant taste, and return. Because it relieves pressure, it can make pain disappear — which is exactly why people ignore it. The infection is still there.

7. A cracked, chipped or injured tooth

A crack or fracture can open a pathway for bacteria to reach the pulp, even when the damage looks minor on the surface. If a tooth has been hit, chipped or cracked — especially if it later becomes sensitive or sore — it should be assessed promptly. For immediate first-aid steps, see our guide to dental emergencies.

Can you need a root canal without any pain?

Yes — and it’s more common than people expect. A nerve can die quietly, an infection can drain through a fistula, or the problem may only show up on an X-ray as a dark spot at the root tip. This is one of the reasons regular dental exams matter: catching an infected tooth before it hurts usually means simpler, more predictable treatment.

What happens if you ignore the signs?

An infected tooth doesn’t recover on its own. Left untreated, the infection can spread into surrounding bone, form an abscess, and in some cases put the tooth beyond saving — turning a routine root canal into an extraction and replacement discussion. Modern root canal treatment is done with local anaesthetic and, for most patients, feels similar to having a filling placed. If dental visits make you anxious, we also offer sedation options to keep you comfortable.

Worried about a tooth? Let’s take a look

If any of these signs sound familiar, don’t wait for the pain to decide for you. Our team at Cornwall Dental Arts can examine the tooth, take an X-ray, and walk you through your options.

Call (613) 932-2058 or request an appointment.

FAQ

Does a root canal hurt?

The procedure is done under local anaesthetic, and most patients say it feels similar to getting a filling. The pain people associate with root canals usually comes from the infection beforehand — treatment is what relieves it.

How do I know if I need a root canal or just a filling?

Only an exam and X-ray can say for sure. Short-lived sensitivity often points to decay a filling can fix, while lingering pain, night pain, or pain on biting suggests the pulp is involved.

Can a tooth that needs a root canal wait?

It shouldn’t. Pulp infection doesn’t heal on its own, and delaying treatment risks abscess formation, bone damage, and losing the tooth entirely.

What happens after a root canal?

The tooth is cleaned, sealed and restored. Back teeth usually need a crown afterward to protect them — see Do You Need a Crown After a Root Canal?

This article is provided for general education and does not replace a dental examination, diagnosis, or individualized treatment plan.