Few phrases in dentistry cause more anxiety than "root canal." But modern root canal treatment is nothing like the outdated reputation it carries. Today, the procedure is comparable in comfort to getting a filling. Here are five signs that you might need one, and what you can actually expect.

1. Persistent Tooth Pain

A toothache that lingers, especially a deep, throbbing pain, is one of the most common indicators of an infected or inflamed tooth pulp. The pain may be constant or may come and go, but if it keeps returning, it is your body signaling that something is wrong beneath the surface.

Not all tooth pain means you need a root canal. Sensitivity to cold that disappears quickly, for example, may indicate something else entirely. But persistent, unprovoked pain warrants a professional evaluation.

2. Prolonged Sensitivity to Heat or Cold

If hot coffee or cold water causes sharp pain that lingers for more than a few seconds after the stimulus is removed, the nerve inside your tooth may be damaged or infected. Brief, fleeting sensitivity is usually not a concern, but prolonged sensitivity, especially to heat, is a red flag.

3. Swelling or Tenderness in the Gums

Swelling near a specific tooth, a small bump on the gum (sometimes called a fistula or gum boil), or tenderness when you press on the area can indicate an infection at the root of a tooth. The infection can create a pocket of pus (abscess) that may drain through the gum tissue.

4. Darkening of the Tooth

A tooth that has turned gray or dark compared to the teeth around it may have experienced trauma or internal decay that has affected the nerve and blood supply. This discoloration happens from the inside out and will not respond to whitening treatments.