Root Canal Treatment Steps: What Happens at Each Stage

The dentist examines the tooth, taps it, tests its response to cold, and takes an X-ray. This confirms that the pulp is inflamed or dead, shows how many canals there are and how curved, and reveals any infection at the root tip. Some teeth need a second angle or a 3D scan when the anatomy is unclear.

This is also the point to decide how many visits are sensible. A straightforward tooth can often be done in one long appointment; an actively draining infection is better split, as covered in is single sitting root canal safe.

The tooth is numbed with local anaesthetic. A thin rubber sheet, the rubber dam, is then clamped around the tooth so that saliva and its bacteria stay out of the canals. This step matters for success and is the one patients most often do not notice.

The dentist drills a small opening through the biting surface of a back tooth, or the back surface of a front tooth, to reach the pulp chamber. The inflamed or dead pulp is removed and the canal entrances are located. Molars can have three or four canals, some of them very fine.

The length of each canal is measured, often with an electronic apex locator and confirmed on X-ray, so that cleaning stops at the right point. Thin flexible files, usually rotary ones, shape each canal into a smooth tapered channel.

Shaping alone does not clear the infection, because bacteria sit in places files cannot reach. The canals are flushed repeatedly with an antibacterial irrigant, such as sodium hypochlorite, and sometimes dressed with a medicament such as calcium hydroxide when treatment is split across visits. Most of the quality of a root canal is decided in this stage.

Once the canals are clean and dry, they are filled with gutta-percha, a rubbery biocompatible material, together with a sealer that fills the gaps. An X-ray is taken to check the filling reaches the right length and has no voids.

The opening is then closed with a filling or a temporary seal. A temporary seal is only a holding measure and leaks over time, so the permanent restoration should follow within weeks.

A root-treated back tooth is brittle and normally needs a crown for cusp coverage. Where very little tooth is left, a post and core may be placed first to hold the crown. The sequence for that is covered in what happens when you get a crown (cap).

A front tooth with a small opening can sometimes be restored with a bonded filling. Either way the treatment is not complete until the tooth is permanently sealed. Our root canal treatment page gives the short version, and root canal side effects describes what to expect afterwards.