Why Has One of My Teeth Turned Grey?

Not all discolouration is the same, and telling the two apart matters:

• External (surface) staining affects many teeth fairly evenly and comes from coffee, tea, red wine, tobacco or simply age. It responds to cleaning and whitening.
• Internal discolouration usually affects one tooth, changing it from within. This is the pattern that suggests a pulp problem rather than a lifestyle stain.

If it is one tooth looking distinctly different from the rest, think internal — and think about why.

Inside a tooth, the pulp contains blood vessels. If those vessels are damaged — by an injury, deep decay, a crack, or a large old filling — blood components can break down and seep into the surrounding dentine, tinting it from the inside. As the pulp loses vitality, the tooth can take on a grey, brown, or darker hue that no amount of brushing removes.

This is why a tooth knocked years ago in a fall or sports incident can slowly darken long afterward. The original injury quietly ended the pulp's blood supply, and the colour change is the visible aftermath. That delayed link to trauma is covered in root canal after a dental injury.

Not always, but it frequently does when the pulp has died, because a non-vital tooth can harbour infection even without pain. A dentist will test the tooth's vitality and take X-rays to check for signs of infection at the root before recommending anything. The purpose of a root canal here is to remove the dead or infected pulp and prevent problems down the line — the same reasoning as in needing a root canal without pain, since a discoloured tooth is often a painless warning sign.

Occasionally, mild discolouration in a still-vital tooth has other explanations, so the vitality tests and X-rays described in how dentists diagnose a root canal guide the decision rather than colour alone.

Often, yes — but the approach depends on whether the tooth needs treatment first:

• If the tooth needs a root canal, that is usually done before addressing appearance.
• Internal (non-vital) whitening can sometimes lighten a root-canal-treated tooth from the inside.
• A crown or veneer may be chosen for a front tooth when whitening is not enough or the tooth also needs structural protection — relevant to restoration options after a root canal and to the aesthetic considerations for front teeth in front-tooth root canal.

The point is that chasing the colour with over-the-counter whitening rarely works on a single internally discoloured tooth, and it skips the more important question of whether the pulp is healthy.

• Book an assessment, even without pain. The colour is a clue that the pulp may be compromised.
• Mention any past injury to that tooth, however long ago — it is often the missing piece of the story.
• Hold off on whitening the single tooth until a dentist has checked it; whitening will not fix internal discolouration and may distract from the real issue.

Once the health of the tooth has been addressed, there are several ways to improve the look of an internally discoloured tooth. Which suits you depends on the tooth, the degree of discolouration, and whether the tooth also needs structural protection:

• Internal (non-vital) whitening. For a tooth that has had a root canal, a whitening agent can sometimes be placed *inside* the tooth to lighten it from within — an approach specific to treated teeth and different from ordinary surface whitening.
• A veneer. A thin custom facing bonded to the front of the tooth can mask discolouration while conserving more tooth structure than a crown, often chosen for front teeth.
• A crown. If the tooth also needs protecting — for example, after significant structure loss — a crown both strengthens and covers it.

Your dentist will weigh appearance against how much healthy tooth remains. There is no single "best" fix; it is matched to the individual tooth, and results vary, so it is worth discussing realistic expectations rather than assuming any option will make the tooth identical to its neighbours.

The most important message about a darkening tooth is one of sequence: health first, appearance second. It is tempting to reach for whitening strips or to ask about a veneer straight away, but a grey single tooth is usually a sign that the pulp has died, and that needs assessing before any cosmetic step. Treating a non-vital tooth's appearance while ignoring a possible infection at the root risks a painful flare-up later and can compromise the very restoration you paid for. So if a tooth is changing colour, book an assessment first; the cosmetic options will still be there once the tooth's health is confirmed, and they tend to work better on a tooth that has been properly treated.

My tooth went grey but doesn't hurt. Is that normal?

A painless grey tooth is common and does not mean it is fine — a dead pulp is frequently painless. It should be examined.

I hit this tooth years ago. Could that be the cause now?

Yes. Trauma can end a pulp's blood supply, and the discolouration may appear months or years later.

Will whitening toothpaste fix a single dark tooth?

No. Surface products act on external stains. Internal discolouration needs a different approach, often after the tooth's health is addressed.

Can the tooth be saved and made to look normal again?

Frequently, yes — with a root canal if needed, followed by internal whitening, a veneer, or a crown depending on the tooth. A dentist will advise what suits your case.

If one tooth has changed colour, let us check whether the pulp is healthy before thinking about appearance. Learn about root canal treatment in Markham or book an assessment, and we will explain your options for both health and looks.