A chipped or broken tooth may not hurt but it can potentially be a big problem. Teeth have liitle tubules which run from the pulp (nerve and blood supply) through the middle layer called dentin. Should these tubules become exposed due to cracks, fractures, trauma , decay, etc, bacteria can invade these tubules and travel to the pulp. If that happens, an infection can occur leading to a serious abscess. This does not necessarily have to "hurt". It can happen without any discomfort. Should an infection occur, bacteria are now free to enter the bloodstream and travel anywhere around the body. The immune system is one such area that can be affected.