I had a root canal with crown and post. The post has broken 2 times in one year.

Hi:Unfortunately without an xray it is difficult to know why the post keeps coming off.  Can you please post an xray of the tooth.Best,Dr. Maddahi

Unfortunately without more information it will be hard to give you much opinion. Sometimes with posts there is simply not enough tooth structure to salvage. If your tooth has come out twice in one year, no dentist may be able to help you save this tooth. If you can send more info, such as photos of the tooth that has fallen out or any xrays, I might be more helpful to you. All the best.