Today’s post is all about the importance of crowning teeth that have been root canalled I will start off with a general rule of thumb. In a perfect world, any tooth that has had a root canal should be crowned. The the real world, all molars should be crowned no matter what, and other teeth should be evaluated for a crown depending on the tooth and its condition.
Why must molars be crowned?
As mentioned, ideally all teeth should be crowned after being root canalled Molars are especially important. This is because they have multiple cusps and different roots associated with those cusps. Look at the picture of a tooth I extracted at my clinic. The roots are flared out. Where the two roots meet is a potential spot for it to crack. If the tooth was crowned it would completely encase the cusps of the tooth and help distribute biting forces more evenly. It also helps hold the tooth together when a large filling or build-up exists.
Why teeth in general must be crowned?
A root canal procedure involves removing the nerve or pulp tissue of a tooth. This is the blood supply of the tooth that normally provides nutrients and moisture. Once the nerve/pulp is gone the tooth starts to “dry out” and it becomes more brittle. In addition to access the nerve/pulp the dentist must drill quite a bit of tooth to get all the way down. This removal of tooth structure also makes the tooth weaker.
How soon after should a root canalled tooth be crowned?
This is a question to be discussed with your dentist. It depends on many factors such as the vitality of the tooth before the root canal, was the tooth necrotic (dead), infection, abscess? As a rule of thumb I would wait a minimum of 3 months and a maximum of 9-12 months before crowning. The reason we wait 3 months for most cases is that root canal therapy is never 100% and we want to make sure the tooth has responded well to treatment. We don’t want to crown it if the tooth ends up needing extra work or even extraction!
A Real Case from my Clinic
The following is an xray and picture from a patient who presented with a chipped filling. On the xray all you can see is that a root canal was done and there is a large filling. The filling was broken into multiple pieces so our plan was to replace the filling and then crown the tooth. After removing the filling it was observed that the tooth was actually cracked in half. The patient did not have any pain associated with it!
The orange coloured material is “gutta percha”, its a natural rubber that is used to seal canals in the roots. As you can see the actually root is split. This tooth needs to be extracted.