Why is the crown on my tooth turning gray ?

More info needed....: Age of crown, materials used. Hard to advise you without this info.Best bet is to ask a local dentist.

I'm assuming you are: Referring to the clinical crown of the tooth and not a "cemented crown". Typical a tooth discolors if the nerve is necrotic; can be due to trauma, deep decay .... . Best to be evaluated by your dentist for appropriate treatment recommendations. Hope this helps.

What kind: If natural crown of the tooth, may discolor from old silver filling, cavity, leaking tooth colored filling, damage to nerve chamber of tooth. If dentist-made crown may discolor from break-down of materials or from leakage of the seal between the crown and the tooth. In either case you need to see your dentist for evaluation and rx. Please do so soon.

Dr Bell agreed