When I was in middle school and I was about 12 years old. I was running to my next class because I thought I was running late, but I didn't. My shoe lase was undone and realize it but I didn't think about time because of I thinking I am late to class. I fell hard on the ground in the hallway and I had a lot of pain. So I went to nurse office to get pain medication mostly tynoldes. So the nurse give me tynoldes, it help me and I had chip a piece of my tooth. So a year later when I was 13 years old, I went my dentist and did a root canal try turn my gray tooth turn back it nautral white color but it didn't. I think I remember when I was 8 years old, my older sister friend was shoveling our backyard and I was close to him. I didn't relaizes then and until it happen. When he pull the shovel over his head. The shovel hate my mouth and my tooth.

A gray tooth is usually a dead tooth, or the tissue underneath it is dead or rotting.

You need to see your dentist to know for sure.

Discoloration of the tooth is usually a sign of internal damage caused by remnants of biologically decomposed pulp tissue, but this is not necessarily irreparable damage. Pulp necrosis is a likely diagnosis if the tooth shows grey/blue or red crown discoloration in combination with an apical radiolucency.