Root canal and crown on back tooth. Now it has broken off at the gum line?

I think in might be that the crown got decemented from the post.go back to your dentist and have him/her look at it , before more damage gets in the way!!
 and keep smiling!
Jaime Cohen DDS MS México city.

Sorry you have had such a traumatic experience with your teeth. I would suggest you consider a second opinion concerning your broken tooth. It is important that you have confidence in your dentist. Usually when a tooth has had a root canal and crown.... and it breaks to the gum line then the chances of saving that tooth is very low. Good luck with your search for a new dentist.

Hi:
Unfortunately without photo and X-ray it is difficult to give you accurate advice.  Please post photo and X-ray of the affected area.  There is a possibility that the post and the crown can be recemented.
Best,
Dr. Maddahi

It sounds as if the post has come out of the teeth . If this is the case it may be able to be recemented. There could also be additional problems but without an xray it's impossible to say. If you are concerned I suggest going to another dentist in your area. 

The outcome will be based on why the crown fractured. If there was a deep cavity underneath or part of the tooth broke it might need to be pulled or could involve more procedures such as crown lengthening to save it. Make sure you let your dentist know about the concerns you have or if there is someone else you feel more comfortable with please seek them out as well. 

Your experience sounds scarier than a Quentin Tarantino movie. I believe that the dental process is just as important as the result. Sounds like your dentist is more concerned with his business than with your experience. Now that your tooth has fractured, you well might need an implant and new crown. Is there some reason why you don't change dentists? Are you more concerned with cost than quality? Many people are and I do not know you well enough to know which is more important to you.