Your tooth was causing you pain, and your dentist recommended that you get it evaluated for a root canal to prevent an extraction or tooth loss.  Now that the tooth has a root canal, the dental care team advises you the tooth needs a crown.  So why does a root canal tooth need a crown?  You are not in pain anymore, why spend the extra time time and finances for a crown?

A root canal procedure requires the general dentist or endondontist to make a hole in the middle of the tooth, and remove all decay in the process.  This is known as an access preparation, and is required to able to gain entry into the pulp chamber and root canal system of the tooth. This access prep is usually deep, as the depth of the access is the length of the entire tooth.  As a result, the tooth may then be weakened due to less natural structure remaining.  When a tooth is weakened, the tooth may have higher likelihood of fracture, especially your back teeth.  The best way to prevent a tooth from fracture is to place a full coverage crown over the remaining tooth structure.  Prior to preparing the tooth for a crown, a buildup (filling) may be required to fill in the hole and support the crown.

When we eat, the bulk of our chewing (occlusal) forces are on the back teeth, the molars and premolars.  Because the posterior teeth take the blunt of the chewing pressure, this subjects the back teeth to possible weakening and fractures on root canal teeth; this reason is why crowns are generally required on root canal teeth, to avoid breakage.  The front teeth typically avoid the majority of chewing forces, and is usually subject to less occlusal stress.  If a root canal was done on a front (anterior) tooth, many times a crown may not be required; a small filling may be all that is needed to fill in the access hole.

If finances and time constraints prevent a root canal tooth from having a full coverage crown, a buildup or temporary filling may be used temporarily to hold the tooth in place until the crown can be done.  How long this filling will last cannot be predicted unfortunately.  But caution is advised as the buildup filling is usually indicated to be inside the crown, and part of the tooth and/or filling may break off and fracture off when chewing.  If a large part of the tooth breaks off, the tooth may not be saveable and require  an extraction, a definite unfortunate setback.

If you have any questions on why a root canal tooth need a crown, please consult your general dentist.

Peter Chien, DMD, MPH
(425) 614-1600