 Simply put, the greatest amount of damage a dentist can do to your tooth is to put a crown on it. The process for preparing a tooth for a crown or cap requires the dentist to grind away the healthiest parts of your tooth to get to the damaged parts. Your tooth is reduced to a small nub and is significantly weakened. The tooth's been so traumatized by the heat of a drill that it may also need a root canal to make the pain stop.