Well, I could feel a tiny bit of movement in the crown, so he tried to pull it off to re-cement it. He couldn't get it off so he used a slide hammer to try and remove it and the whole tooth broke off at the gum line. It did have a large filling in it and he did have to do a root canal through the crown a couple of years ago just after he put it on.
a good dentist will cement a crown on top of the tooth root that is exposed. Others will pull it and implant a tooth, others will put a fixed partial over the space by crowning the two teeth on either side of the space.