I have a tooth growing over a tooth. Half of the baby tooth cracked and fell out the other half remains in my mouth. The half in my mouth has a weird substance attatched to it. It is black, hard, rough, and almost feels like a rock. I want to know what it is and if it will do any harm.
You need to extract the baby tooth. The Black tooth you are saying is probably a root piece that you need to extract. After this you may need to go for orthodontic alignment of the permanent tooth that was coming on top of the baby tooth