Tiff, I was reading about root canals and I guess it is common enough for the thing to break up in the canal!
"A file may break. The tip of a file may break off inside the tooth. Usually, it's possible to leave the piece in the tooth and finish the root canal. But if the cleaning of the canal has not been finished, the file piece may have to be removed. Sometimes this can be done from the top of the tooth. However, in some cases, the file can only be removed through a surgical procedure called an apicoectomy. A small incision is made in the gum to access the root of the tooth, and the portion of the root containing the file piece is removed."
I heard my dentist tell the assistant that he didnt want the skinny skinny one because it often breaks!