My tooth is turning black

You might have noticed at a person, one tooth that is different from the others, it may have been darker and strange looking. The fact is that events associated with causing or treating tooth nerve tissue damage can result in gray or brown tooth discoloration. These events include traumatic incidents (an accident or fall) and root canal treatment. The stain only forms within those teeth (typically one or just a few) that have been directly affected by the event.

Teeth whose nerve tissue has degenerated (or have had root canal treatment so to treat this problem) often undergo a generalized darkening.

One theory explaining this phenomenon suggests that the staining effect is caused by the release of iron pigments from decomposing hemoglobin-containing red blood cells within the tooth. These iron compounds penetrate into the dentin layer of the tooth, thereby creating a staining effect.

Tooth trauma can cause tooth nerve degeneration, either on a brief or extended (years) time frame. The darkening of any individual tooth, especially one that has a history of trauma such as having been bumped in an accident, can indicate that there is a problem with the health of the nerve inside. For this reason, any individually darkened tooth should always be evaluated by a dentist keep that in mind.

Direct link:

http://www.animated-teeth.com/teeth_whitening/t2a-whitening-tooth-staining.htm#tooth.trauma