The short answer
What to know first
A painful tooth may need root-canal treatment when the tissue inside it is irreversibly inflamed or infected and the tooth can be restored. Pain alone cannot confirm this: examination, clinical tests and often an X-ray are needed.
What root-canal treatment addresses
The dental pulp is the soft tissue inside a tooth. Deep decay, cracks, trauma or previous dental work can affect it. Root-canal treatment removes affected tissue from the canal space, which is then cleaned, shaped and sealed before the tooth receives a suitable final restoration.
The same type of pain can come from different teeth or tissues, so treatment should not be chosen from symptoms alone.
Possible signs and symptoms
Symptoms that can prompt assessment include pain with hot or cold, pain on biting, spontaneous or lingering pain, swelling, tenderness or a change in the tooth. Some affected teeth have few symptoms and are identified during examination or imaging.
These signs do not prove that root-canal treatment is required. A crack, gum problem, bite issue, decay or another nearby tooth may produce similar symptoms.
How the tooth is assessed
The dentist reviews the symptom pattern, relevant history and previous treatment, examines the tooth and nearby tissues, and may perform tests of biting, tapping or pulp response. A digital dental X-ray may help assess the tooth and surrounding bone.
The tooth must also be checked for cracks, remaining structure and whether it can be restored after internal treatment.
Treatment overview
Where root-canal treatment is appropriate, the tooth is accessed and the canal system is cleaned, shaped and sealed. Treatment may involve more than one visit, and a temporary filling may be used between stages.
Appointment number and length vary with the tooth, infection, anatomy, restoration needs and response. A universal timeline should not be promised.
Alternatives and restoration
Depending on the diagnosis, options may include a filling, monitoring, root-canal treatment or removal of the tooth. Some cases may need referral. A root-treated tooth may need a crown or another final restoration to rebuild it.
Root-canal treatment aims to retain a suitable natural tooth, but healing and long-term retention cannot be guaranteed.
When to seek urgent care
Seek prompt professional assessment for increasing facial swelling, severe worsening pain, fever or feeling significantly unwell. Breathing or swallowing difficulty, rapidly spreading swelling or swelling near the eye or neck needs urgent appropriate healthcare attention.
Frequently asked questions
References
- Root canal treatment — NHS. Accessed . Opens in a new tab.
Medical review information
This guide is an editorial draft awaiting documented clinical review. It was last updated on . A reviewer name and last-reviewed date will appear only after approval.