What is it?
The aim of root canal treatment is to clean the infected tissue from the canal system and fill the space so it does not leak. The system is complex, so sometimes a lateral canal, an isthmus or an unaccounted-for extra root is missed, and bacteria go on living there.
The other usual route is reinfection: if the restoration above leaks after the canal has been filled, or the tooth fractures, bacteria come back in from the mouth. That is why sealing the tooth properly after root canal treatment is as decisive as the treatment itself.
Signs
You will not necessarily have all of these at once.
Why does it happen?
- 01
A missed canal
If an extra canal, common in upper molars, is not found, the infection continues there.
- 02
A leaking restoration
However well the canal is filled, bacteria return once there is leakage from above.
- 03
Root fracture
A root-treated tooth is brittle; without a protective restoration the risk of a vertical root fracture rises.
- 04
A persistent cyst
In some cases the lesion at the root tip does not resolve on its own even after the canal is cleaned.
How is it treated?
The first option is usually retreatment: the old filling is removed, the system is cleaned and shaped again, and refilled. Working under magnification makes finding missed canals markedly easier.
Where retreatment is not possible or does not work, root-end surgery (apicectomy) may be used. If the root has fractured vertically the tooth usually cannot be saved, and an implant is considered after extraction.
- A white bump or draining point on the gum
- Pain on biting returning
- Facial swelling or fever
- New movement in the tooth
How is it prevented?
- Do not postpone covering the tooth with a protective restoration after root canal treatment
- Keep up the review radiographs; healing at the root tip is followed over months
- Arrange protection if you clench; the fracture risk is higher in these teeth
Frequently asked questions
- If root canal treatment fails, does the tooth have to come out?
- No. In most cases the tooth can be kept with retreatment or root-end surgery. Extraction generally arises with a vertical root fracture.
- If there is no pain, is there no problem?
- Inflammation at the root tip can progress painlessly for a long time and show only on a radiograph. That is why reviews matter.
This content is for general information and does not replace an in-person examination. Symptoms overlap between conditions, and a diagnosis can only be made clinically.