Q. Hello, I am 14 years old and recently noticed one of my back teeth starting to chip from the inside, then today the outside chipped off do about 1/3-1/4 of my tooth is missing my mother looked and said it was black and she thinks it has spread to the tooth next to it. I have never had good dental hygiene but I have learned my lesson. I am not in any pain and my tooth does not smell. But what should I do about it, and will it cost a lot?,