Grey teeth stains have several causes.
Medications:
Grey teeth stains can be caused by some medications, especially in young children.
Metal:
Some materials used by dentists to repair teeth, such as silver fillings, may contribute to grey stains on teeth over time.
Motion:
The trauma may disrupt the blood flow to a tooth or teeth and cause grey teeth stains. Learn how to successfully remove stains from teeth here with Oral-B. Also, some people have teeth that are naturally greyish, and they may feel like they have grey stains on teeth even if they don’t.
The trauma of grey teeth stains
Damage from a blow or fall can disturb enamel formation in kids whose teeth are still developing. The disruption to developing teeth can cause grey stains on teeth. Trauma also can cause grey teeth stains in older children and adults whose teeth are fully developed. The trauma may disrupt the blood flow to a tooth or teeth and cause grey teeth stains.