Perhaps your teeth are not as white as you'd like them to be, but it's more or less a given that they are all the same colour. This is why it can be disconcerting when there's a break in this uniformity of colour. A single grey tooth can be a cause for alarm, and no matter how much you clean it with whitening toothpaste (or even treat it with a teeth whitening kit), this discolouration doesn't seem to shift. So what can cause a single tooth to slowly turn grey? And what can you do about it?

Trauma and Antibiotics

There are a number of reasons why a tooth can turn grey. There is one key reason which you might be well aware of. Blunt force trauma to the site (a blow to the mouth) could have effectively killed the tooth, allowing the dental pulp (the nerve inside the tooth) to slowly die. The tooth is intact, but the nerve is dead, leading to the internal degradation of the tooth.

Usage of an antibiotic known as tetracycline during the formative phase of your teeth (when you were a child and your adult teeth were developing) can also cause this grey colour to form over time. This could be something you were unaware of, since it's not as though most adults will remember antibiotics that were prescribed during childhood.

Root Canals

Your dentist will discuss treatment options with you. When the dental pulp has died, your dentist might opt to perform a root canal to remove the nerve. This should prevent further degradation of the tooth, although it will not correct the colour. If the cause of the grey tooth is suspected to be tetracycline, then the dental pulp is unlikely to be damaged (unless it has occurred due to a secondary unrelated cause) and so a root canal will not be needed.


Your tooth can't be restored to its former colour, and the most straightforward solution is generally a dental veneer. This is when a wafer-thin piece of porcelain or porcelain laminate is fabricated to fit precisely over the outward facing side of the tooth. It's permanently adhered into place and corrects the colour imbalance between your teeth. The preferred shade of the veneer is important if you're considering having your teeth whitened in the foreseeable future, as the veneer cannot be whitened (and so the colour of the veneer is the maximum level of whiteness that can be achieved without creating a colour imbalance).

A grey tooth can really stand out when you smile, but your dentist should be able to correct the issue with a minimum of fuss.