What Is a Root Canal, and Why Would You Need One?
A root canal is a procedure that removes infected or damaged tissue (called the pulp) from inside a tooth. The pulp contains nerves, blood vessels, and connective tissue. When it becomes inflamed or infected — usually due to deep decay, repeated dental procedures on the same tooth, or a crack — the tooth can cause significant pain and, without treatment, may need to be extracted entirely.
At our Toronto endodontic practice, we perform root canals using modern rotary instruments and digital imaging that make the procedure faster, more precise, and far more comfortable than what most patients expect. But the key to saving a tooth is catching the problem early. Here are the seven signs that should prompt you to book an appointment.
1. Persistent Tooth Pain
Pain that does not go away is the most common indicator that something is wrong inside the tooth. The pain may be constant, or it may come and go but always returns. It might radiate to your jaw, face, or other teeth. While tooth pain can have many causes — a cavity, a sinus infection, gum disease — persistent or worsening pain in a specific tooth often points to pulp damage that only a root canal can resolve.
Pay particular attention to pain that feels deep within the tooth rather than on the surface. This deep, throbbing ache typically indicates that the nerve inside the tooth is inflamed or dying.
2. Lingering Sensitivity to Hot and Cold
It is normal to feel a brief twinge when you sip hot coffee or bite into ice cream. What is not normal is sensitivity that lingers for thirty seconds or more after the hot or cold stimulus is removed. This prolonged reaction suggests that the nerve inside the tooth is damaged and struggling to recover — a hallmark sign of irreversible pulpitis, which is treated with a root canal.
3. Swollen or Tender Gums
Swelling near the base of a painful tooth is a red flag. When the pulp becomes infected, bacteria can spread beyond the tooth and into the surrounding bone and gum tissue, causing an abscess. You may notice a localized area of swelling on the gum that feels warm and tender to the touch. In some cases, the swelling may extend to the face or neck — this is a dental emergency that requires immediate attention.
Even mild gum swelling that comes and goes near a specific tooth warrants investigation. Infections do not resolve on their own; they need professional treatment.
4. A Darkened or Discoloured Tooth
When the pulp inside a tooth dies, the tooth can gradually darken to a grey, brown, or yellowish hue. This discolouration happens because the internal tissue is breaking down and byproducts are seeping into the hard structure of the tooth. If you notice that one tooth is visibly darker than its neighbours — and it has not been stained by food or drink — the pulp may be necrotic.
A darkened tooth does not always hurt, which is why many patients delay treatment. But an infection inside a non-vital tooth can still spread to surrounding bone and tissue. Do not wait for pain to appear.
5. Pain When Chewing or Touching the Tooth
If it hurts to bite down on a particular tooth or if the tooth feels sore when you press on it with your finger, the ligament around the root may be inflamed due to infection. This is called symptomatic apical periodontitis, and it often accompanies a tooth that needs root canal therapy.
This symptom is especially telling when it appears alongside other signs on this list. Isolated bite sensitivity can sometimes be caused by a high filling or minor trauma, but combined with persistent pain or temperature sensitivity, it strongly suggests pulp involvement.
6. A Cracked or Chipped Tooth
A tooth that has been cracked, chipped, or fractured — whether from an injury, biting something hard, or clenching and grinding — may allow bacteria to reach the pulp. Even if the crack is too small to see with the naked eye, it can create a pathway for infection. Cracked teeth do not always produce immediate symptoms, but they may develop pain, sensitivity, or swelling weeks or months later as the infection takes hold.
If you have cracked a tooth, see your dentist promptly even if it does not hurt. Early treatment with a crown may prevent the need for a root canal altogether. But if the crack has extended to the pulp, root canal therapy becomes necessary to save the tooth.
7. A Pimple on Your Gums (Fistula)
A small, pimple-like bump on the gum near a tooth is called a fistula or sinus tract. It is your body's way of draining pus from an infection at the root tip. The fistula may come and go, and you may notice a bad taste in your mouth when it drains. While it might seem like the problem is managing itself, the underlying infection is very much active and will continue to destroy bone if left untreated.
A fistula is one of the most definitive signs that root canal therapy is needed. If you notice one, book an appointment as soon as possible.
When to See Your Dentist Urgently
Any of the seven signs above warrants a dental visit, but certain situations call for urgent or emergency care:
- Facial swelling that is spreading or making it difficult to swallow or breathe
- Fever accompanied by dental pain
- Severe, unrelenting pain that over-the-counter medication cannot control
- A visible pus discharge from the gums
These symptoms may indicate a spreading infection that can become dangerous if not treated promptly. Call our office immediately or visit your nearest emergency department.
What Happens If You Delay Treatment
Ignoring the signs of a failing tooth pulp does not make the problem go away. Without treatment, the infection can spread to the jawbone, causing a dental abscess that destroys surrounding bone tissue. In severe cases, the infection can enter the bloodstream — a condition called sepsis — which is life-threatening. Even in less extreme scenarios, delaying a root canal often means the tooth deteriorates to the point where it cannot be saved and must be extracted, leading to the additional cost and complexity of a dental implant or bridge.
The earlier you seek treatment, the simpler and more predictable the outcome. For a detailed walkthrough of what the procedure involves, read our guide on what to expect during a root canal.
Do Not Wait — Book Your Assessment
If any of these signs sound familiar, the best thing you can do is get a professional evaluation. At our Don Mills, Toronto practice, we use advanced diagnostic tools to determine exactly what is happening inside the tooth and recommend the most conservative treatment possible. Call us at (416) 551-2211 or book online to schedule your appointment.