I have a black tooth — what are my options?

Q. Hi Doc, I have a front tooth that is slowly getting darker. I previously had root canal treatment done and a white filling on top, but I noticed it getting a bit darker over the last few months. What are my options?

Front teeth becoming dark is a very common problem people have, especially on root canal treated teeth.

Following root canal treatment, even though the root canal filling has been sealed with a filling, leakage around this is still possible. As a result of leakage, the root canal treated tooth becomes darker than the adjacent teeth.


Before even considering getting a veneer or crown placed on this tooth to mask the colour, it’s important to eliminate the dark stain. This is because the crown or veneer itself is slightly transparent (if you opt for porcelain), and any stain of the underlying tooth will show through.

Internal bleaching is the best method to eliminate the dark stain. Its achieved through placing a whitening agent directly inside the root canal treated tooth and left for a short period of time — usually for 3–7 days.

External bleaching alone, where the whitening agent is placed on the outside of the tooth (LiftWhite, Zoom Whitening) does not really help with these cases — it may make the darkened tooth more obvious as adjacent become whiter.

However, by using internal bleaching on the darkened tooth, and then utilizing external bleaching in combination, you’ll be able to achieve a consistent white smile.

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