Is a root canal painful?

Root canal treatment has the worst reputation of any routine dental procedure, and the reputation is mostly borrowed from the toothache that leads up to it. The treatment itself is done under local anaesthetic and, for most people, feels like a long filling. Here is what to expect, plainly.

Why it has the reputation it has

A tooth needs a root canal when the nerve inside it is inflamed or has died, usually from deep decay, a crack or an old filling. That inflamed nerve is what causes the throbbing, lingering, wake-you-at-night pain people remember. By the time they are in the chair, they associate the whole episode with pain. The treatment is what ends it.

What the appointment feels like

The tooth is numbed first, and the dentist checks it is fully numb before starting. A small rubber sheet isolates the tooth to keep it dry and clean. The nerve space inside the root is then cleaned, shaped and filled, which takes from forty-five minutes to an hour and a half depending on the tooth: front teeth have one canal, molars three or four. You feel pressure and vibration, not pain. An acutely inflamed nerve can occasionally be harder to numb completely; if you feel anything sharp, say so, and more anaesthetic is given.

Afterwards

Some tenderness when biting for a few days is normal and is managed with ordinary painkillers; the tissue around the root tip is settling. A tooth that has had a root canal is more brittle than it was, so a back tooth usually needs a crown within a few weeks to protect it: the plan says whether yours does.

One visit or two

Where the tooth is not infected and the canals are straightforward, treatment can often be completed in a single visit. Where there is active infection or the anatomy is complex, it is done over two visits with a medicament left inside between them. Which applies is decided on what the X-ray and the tooth show, not in advance.

What can go wrong, and how often

Root canal treatment succeeds in the large majority of cases. The things that occasionally happen are a canal too fine or curved to clean fully, a crack in the root that was not visible before, or an infection that does not fully settle. Each has an answer: retreatment, a small surgical procedure at the root tip, or, rarely, removal and replacement, and the root canal that did not settle guide explains how that is decided.

The alternative

The alternative to a root canal is removing the tooth. That is sometimes the right answer for a tooth with too little left to restore, but a natural tooth that can be kept is generally worth keeping; an implant or bridge is a good replacement, not a better original.

If a tooth is aching, call during clinic hours rather than wait: a dental emergency slot is for exactly this. The root canal treatment page describes the stages in full.