I just discovered a hairline crack in my front tooth HELP? I am really upset about this. I'm 23 years old and today I put down the mirror and looked at my teeth and the light from the sun illuminated the crack in my tooth. It appears to go from the top to the bottom. Right now I can't see it unless I look at it in bright light or if I look at it very closely in the mirror but I m worried Will it get worse and discolor inside the crack? What could have caused this? Will my tooth eventually try to split apart? The crack is down the middle. Is there anything to repair this? Thank you in advance.