Why the colour change takes so long to show
A knock damages the small blood vessels inside the tooth. When they bleed, pigment from the blood seeps into the tiny channels that run through the hard tissue and darkens there over time. It has to spread a fair way before anything is visible from outside, which is why the difference usually stands out weeks or even months later rather than the next morning.
Pink, grey or yellow: what each shade suggests
Colour on its own is not a diagnosis, but it does point in a direction. Two things matter to a dentist: the shade you noticed first, and how it has moved since. Looking at the tooth in daylight, next to its neighbours, makes both easier to judge.
- A pinkish tint is usually what recent bleeding inside the tooth leaves behind. It shows up in the first weeks and often fades on its own.
- A grey or dark brown shade points more towards the living tissue inside the tooth having been lost. This colour can deepen over the following months.
- A yellower, duller tooth generally means extra hard tissue has built up inside. Such a tooth is usually still alive, though its canal narrows.
No pain does not mean no problem
Most teeth that darken after a knock do not hurt at all. Once the tissue inside dies, feeling goes with it and a quiet spell begins. Infection can settle around the root tip during that spell and show up first on an x-ray. Painlessness is no substitute for follow-up: a tooth that has changed colour is checked at set intervals.
Baby teeth follow a different course
Grey front baby teeth are a common sight after a toddler falls. Some of these teeth win back part of their colour, others stay dark yet cause no trouble until they come out on their own. A darkened baby tooth does not automatically need root canal treatment. What matters is not the shade but whether there is a bump on the gum, swelling or pain, and whether the tooth has become loose. The permanent tooth forming underneath is followed on x-rays.
Some colour changes reverse on their own
Not every dark tooth stays dark. Pinkish and lightly greyish shades from the first months can lift again if the tissue inside recovers. Where that happens it is usually clear within 2–6 months, and it varies from person to person. Lightening is a welcome sign, though on its own it is no proof that the tooth is sound, so the checks carry on.
A tooth that has taken a knock can still change colour years later, which is why follow-up is measured in years rather than weeks.
What happens at a check-up
The tooth is compared with its neighbours and often photographed for the record. Cold and electric tests show whether it still responds; because they can mislead in the weeks just after an injury, they are repeated later on. An x-ray shows whether anything has changed around the root tip. Checks are closer together in the first year and spread out after that.
What can be done about a dark tooth
If the tooth is still alive, watching it is often enough. If the tissue inside has been lost, root canal treatment comes first, after which a bleaching agent can be sealed inside the tooth to lighten the shade. This does not work equally well in every tooth, and some of the colour may creep back over the years. Where lightening falls short, composite can be bonded to the front surface or a veneer considered. Which route suits depends on the state of the root and how much sound tissue is left.
Ofte stilte spørsmål
How long after an injury can a tooth change colour?
It can begin within the first week, but more often it is noticed a few months later, and in some teeth the change appears years afterwards. That is why a tooth that has taken a knock is followed for a while even when it looks entirely normal.
Will a darkened tooth go back to its old colour?
Some do. Pinkish and lightly greyish shades from the first months can lift as the tissue inside recovers. Deep grey shades usually stay. Lightening is a welcome sign, but it is no proof that the tooth is sound, so the checks continue.
Does every dark tooth need root canal treatment?
No. The decision rests on whether the tooth still responds to the tests and whether the x-ray shows change around the root tip, not on the shade. A tooth that is still alive is often simply watched.
My child's baby tooth has gone grey. Does it have to come out?
Greyness on its own is not a reason to take the tooth out. If there is no bump on the gum, no swelling and no pain, and the tooth is not loose, most such teeth stay in place until they come out naturally. The permanent tooth underneath is followed on x-rays.
Can whitening lighten a tooth that darkened after a knock?
Whitening applied from outside usually falls short here, because the colour comes from within the tooth. Once the living tissue has been lost, a bleaching agent sealed inside the tooth after root canal treatment is more dependable, though the result varies from tooth to tooth.
The tooth does not hurt. Is a dental visit still needed?
Yes. When the tissue inside dies, pain goes with it and the quiet spell can last a long time. Changes around the root tip are seen first on an x-ray. A painless tooth is checked after an injury too.
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Papatya Dental
Denne artikkelen bygger på den kliniske erfaringen til teamet hos Papatya Dental og blir gjennomgått for riktighet før publisering.
- Sist oppdatert:
- 2026-08-27
- Redaksjonell kontakt:
- icerik@papatyadental.com