A toothache can be a sign that the soft tissue inside a tooth — the pulp — is damaged or infected. It can also be caused by many other things. Knowing which symptoms are worth checking helps you decide when to call, but no symptom list can tell you whether you need root canal treatment. Only an examination can do that.
Short answer: root canal treatment is needed when the pulp inside a tooth is infected or irreversibly damaged. Signs that may lead to that finding include pain that lingers or wakes you at night, lingering sensitivity to heat, pressure pain on biting, swelling or a gum boil, and a tooth that has darkened.
Symptoms that may prompt an assessment
Pain that lingers
Sharp sensitivity to cold or hot that fades within a few seconds is common and often related to recession or a filling. When the pain continues for minutes after the bite or drink, or starts without any trigger, it can point to pulp inflammation. Pulp pain can also radiate to other teeth or to the jaw, which is one reason an exam is needed to locate the actual tooth.
Pain that wakes you at night, or throbs
Pain that is there when you lie down, wakes you from sleep, or feels like pressure in the jaw can be a warning sign. Lying flat changes the blood flow to the head and can make some types of tooth pain more noticeable.
Pain on biting or tapping
Discomfort when chewing on one side, pain when the tooth is tapped, or a tooth that feels slightly "high" when you close your mouth can indicate inflammation around the root or a cracked tooth. A cracked tooth may not show on a basic check and can be easy to miss.
Swelling or a gum "boil"
Swelling near the gum, a pimple-like spot on the gum, or tenderness over the root of a tooth can be a sign that infection has spread beyond the pulp. This is not something to leave to see if it settles.
A tooth that has changed colour or become numb
A single tooth that gradually darkens or looks different from its neighbours can indicate that the pulp has died, often after trauma. A tooth that no longer feels hot or cold when its neighbour still does can be a sign that the nerve has lost function. Both are reasons for an assessment, not a diagnosis.
Symptoms that are not a diagnosis
Gum pain, soreness after eating, sensitivity that comes and goes, and a dull ache in the jaw are common with gum disease, sinusitis, muscle tension or bruxism (tooth grinding), and can also follow recent dental work. Gum problems are not solved by root canal treatment and vice versa, which is why identifying the cause matters before any treatment is chosen. Our guide to gum disease signs covers a different set of symptoms.
How a dentist assesses the cause
A root canal assessment is not a single test. Your dentist typically combines:
- A discussion of your symptoms — when they started, what triggers them and how long they last
- An examination of the tooth, gum and surrounding area
- Percussion and palpation tests — gentle tapping or pressure to see how the tooth and gum respond
- Cold testing of the tooth to see how the pulp responds
- Dental X-rays to look for decay, infection or changes around the root
- Sometimes a temporary dressing or observation over a few days
The diagnosis then decides whether root canal treatment is appropriate, whether a simpler restoration is suitable, or whether the tooth cannot be saved. Our root canal treatment page explains the process in more detail.
Treatment choices and what to ask
If root canal treatment is recommended, ask how many appointments it will take, what restoration will follow, what the alternatives are and what happens if the tooth is not treated. Your dentist should also give you a written estimate that separates the root canal fee from the restoration or crown.
- Is the pulp infected or irreversibly inflamed, and how was that established?
- Can the tooth be retained, and is a crown or filling needed afterwards?
- What are the alternatives, and what happens if I choose to wait?
- What does the full plan cost, including the restoration?
- What should I expect after treatment, and what counts as a problem?
When to call us
Contact the clinic if pain lasts more than a day or two, wakes you at night, or comes with swelling or a bad taste near a tooth. If you have a fever with facial swelling, or swelling that is spreading around your eye or neck, or you have difficulty breathing or swallowing, seek emergency medical care — call 000 in Australia.
For pain that needs urgent attention, see urgent dental care or call us on (07) 5563 1201.
Not sure whether a tooth needs root canal treatment?
Tell us when the pain started, which tooth is affected and whether you have swelling. We can book an assessment to find the cause.
Related: root canal treatment, urgent dental care, root canal treatment explained.