A root canal is needed when the pulp (nerve tissue) inside your tooth becomes infected or dies. The seven most common signs are: persistent throbbing pain, lingering sensitivity to hot or cold, a darkened tooth, swollen or tender gums, a pimple-like bump on the gum, pain when biting down, and a chipped or cracked tooth with deep pain. If you notice any of these, see a dentist promptly — early treatment can save the tooth.
What Causes a Tooth to Need a Root Canal?
Every tooth contains a soft core called the pulp, which houses nerves, blood vessels, and connective tissue. When bacteria reach the pulp — through deep decay, a crack, or repeated dental procedures — the tissue becomes infected or inflamed. Left untreated, the infection can kill the nerve, form an abscess at the root tip, and eventually destroy the surrounding bone.
A root canal removes the damaged pulp, disinfects the inside of the tooth, and seals it so it can remain in your mouth and function normally. The earlier the infection is caught, the simpler and more predictable the treatment tends to be.
7 Warning Signs You May Need a Root Canal
1. Persistent, Throbbing Toothache
A deep, throbbing pain that does not go away on its own is one of the most telling signs of pulp damage. The ache may be constant or come in waves, and it often radiates to your jaw, ear, or neighbouring teeth. Unlike a mild cavity ache that only appears while eating, pulp-related pain can wake you up at night and persist even when you are not chewing.
If your toothache has lasted more than a day or two without improving, have it assessed as soon as possible.
2. Lingering Sensitivity to Hot or Cold
A brief twinge when you sip iced water or hot coffee is common and usually harmless. But when the sensitivity lingers for 30 seconds or more after the hot or cold stimulus is removed, it suggests the nerve inside the tooth is inflamed or dying. This prolonged sensitivity is a hallmark sign that distinguishes pulp damage from ordinary tooth sensitivity.
3. A Darkened or Discoloured Tooth
A tooth that has turned noticeably grey, dark yellow, or brownish compared to the teeth around it may indicate that the pulp inside has died. The discolouration occurs because the internal tissue is breaking down and the by-products stain the tooth from the inside out. If you notice one tooth changing colour without an obvious external cause such as staining from food, it is worth getting it checked.
4. Swollen or Tender Gums Near a Specific Tooth
Localised gum swelling — particularly around just one tooth — can signal that an infection is spreading from the tooth root into the surrounding tissue. The gums may feel tender, puffy, or warm to the touch. In some cases, the swelling may extend to the face or neck, which requires urgent dental attention.
Gum swelling can also indicate gum disease, so a professional assessment is important to determine the cause.
5. A Pimple-Like Bump on the Gum (Gum Boil)
A small, persistent bump on the gum near a painful tooth is called a fistula or gum boil. It forms when an abscess at the root tip creates a drainage channel through the bone and gum tissue. The bump may come and go, and it sometimes drains a salty or unpleasant-tasting fluid. A gum boil is a strong indicator that the pulp is infected and a root canal is likely needed.
6. Pain When Biting Down or Touching the Tooth
If a specific tooth hurts sharply when you bite down on food or press on it with your finger, the ligament around the root may be inflamed due to a pulp infection spreading beyond the tooth. This is different from the general soreness of a new filling — the pain is localised to one tooth and does not improve over a few days.
7. A Cracked or Chipped Tooth With Deep Pain
A visible crack or chip that is accompanied by deep, aching pain may mean bacteria have entered the pulp through the fracture line. Even a hairline crack that is not visible to the naked eye can serve as a pathway for infection. If a cracked tooth starts producing any of the other symptoms on this list — throbbing pain, sensitivity, swelling — the pulp may already be compromised.
What Should You Do If You Notice These Symptoms?
If you are experiencing one or more of the signs above, the most important step is to see a dentist as soon as you can. Early treatment gives you the greatest chance of saving the tooth with a straightforward root canal, rather than needing an extraction and a replacement such as a dental implant.
At your appointment, your dentist will examine the tooth, take an X-ray to check the root and surrounding bone, and may test the nerve's vitality using a cold test. Based on the findings, they will recommend the appropriate treatment — which may be a root canal, a filling, or observation depending on the severity.
Not Every Toothache Means a Root Canal
It is worth noting that not all tooth pain signals a root canal. Some common causes of toothache that do not require one include temporary sensitivity after a dental filling, gum recession exposing the root surface, sinus pressure mimicking upper-tooth pain, and teeth grinding (bruxism) causing generalised soreness.
A dentist can distinguish between these causes and a genuine pulp infection. The key difference is usually in how long the symptoms last and whether they are localised to a single tooth.
How Root Canal Treatment Works
If your dentist confirms that a root canal is needed, the procedure is simpler than most people expect. Under local anaesthesia, the infected pulp is carefully removed, the canals inside the root are cleaned and disinfected, and the space is sealed with a biocompatible material. A crown is usually placed afterwards to protect the treated tooth and restore its full strength.
Most root canals are completed in one to two visits, each lasting 60–90 minutes. The procedure itself is comparable in comfort to having a filling done.
Root Canal Cost at Trust Dental Surgery
At Trust Dental Surgery, root canal treatment starts from $650 (before GST). The cost depends on which tooth is being treated — front teeth with a single canal are less complex, while molars with multiple canals cost more.
| Item | Cost |
|---|---|
| Root canal — front tooth | From $650 |
| Root canal — premolar | From $750 |
| Root canal — molar | From $1,200 |
| Crown (quoted separately) | $600 – $1,500 |
| Flexi-MediSave (aged 60+) | Up to $200/year |
| CHAS subsidies | May apply for eligible patients |
All prices are before GST (9%). For a full breakdown of costs and payment options, visit our root canal cost guide.
Related Reading
- Root Canal Treatment: What to Expect — step-by-step walkthrough of the procedure, recovery tips, and aftercare.
- Root Canal vs Extraction: Which Is Right for You? — comparing the two options when a tooth is severely damaged.
- Root Canal Cost in Singapore (2026) — detailed pricing, Medisave, CHAS, and Flexi-MediSave breakdown.
