Root Canal Tooth with Very Little Tooth Structure
I  recently completed more continuing dental education at our annual convention in Atlanta. It always provides the  opportunity to learn new techniques and revisit and update my views and knowledge on the treatment of various dental situations.
A condition which recently came to attention is the broken root canal tooth. One way this presents is when a patient tells me that their crown fell off and they need it recemented…except that all of the tooth structure is sitting inside the crown and there is absolutely no tooth structure left to place this crown or any crown. But what if there is some tooth left? Through the years of study and practice, I have reached my own educated conclusions.
In some cases with limited tooth structure, a post can be placed into the middle of root, where there is a space from the root canal treatment. Fiber posts are strong, but more importantly, this post will flex along with the natural tooth, lessening the chance of a root fracture. This situation sometimes happens with a large metal post and the tooth can no longer be saved.
One consideration is the bite (occlusion) of that particular tooth in the mouth. If someone has a deep overbite putting unfavorable horizontal forces on the tooth, the post with its buildup material may not hold up to that force. In this case the tooth needs to be extracted and a suitable replacement (implant and crown, fixed dental bridge or a removable partial denture) needs to be fabricated.
I have a patient who fits into this category. She had a root canal and a crown done years ago, but there seemed to be too much tooth missing to restore this permanently.  I just recemented her crown with temporary cement .   It’s been four years and, because of other dental issues followed by some serious medical issues, we just haven’t gotten around to the having this tooth extracted and placing an implant. But in the four years, the crown fell off only one time with the use of temporary cement. So based on this additional information, I have altered her treatment plan to receive a post and buildup, followed by having a new crown fabricated. I feel confident that this will be a good long term solution for her, eliminating the need to have the tooth extracted and an implant placed.