I broke my front two upper teeths into half long way back in 2003 when I was in school. After that I had Root Canal done on them. After that in 2009 I got my braces on for one and a half years, and in 2011 I had artificial crowns fitted on my front two broken teeths. Since then the crowns have been working good. Now a few days back, I've been experiencing some pain in one of the crowns. Whenever there's something hard to bite, or the lower teeths, touch the tip of the upper teeth crown, it stings for a few seconds. The tips of the crown are sensitive, but the rest of the crown feels sturdy and painless when held in fingers. Can you guide, with what might be the problem?