Doctor's Answers (1)
A tooth may become discoloured for reasons other than a dead/infected nerve. After a traumatic injury, the nerve (which is still alive) may lay down scar tissue internally, causing the tooth to become more yellow over time.
Other causes of discolouration include external staining from:
Before the nerve dies completely, the internal bleeding from the nerve tissue stains the tooth a dark grey or brown colour. A dead nerve will not respond to vitality testing (such as cold). If there is an infection within the nerve canal, the bone around the root of the tooth may start to resorb in response. This can be seen when an xray of the tooth is taken.
Depending on the cause of the discolouration, there are different options to restore the original colour of the tooth, such as bleaching. These can be discussed with your dentist after the nerve status of the tooth is confirmed by clinical tests.