I can’t remember the exact date, but in the fall of 2000, I had a root canal on a left canine tooth. I’ve relocated three times since then. Now that I live in Georgia, my new dentist says that I need a crown on the tooth to prevent it from breaking. Since I received the crown, I’ve had at least six different dentists. Not one of them has mentioned putting a crown on the tooth. There were so many problems with the tooth before the root canal that I’m nervous about another procedure. And I don’t like to be sedated unnecessarily. My hygienist can’t clean my teeth without nitrous oxide, and she is a gentle hygienist. Do I really need a crown, or is this dentist pushing unnecessary treatment? Thanks. Emily from Witchita Falls, OK
Root canal treatment weakens a tooth and increases the risk of breaking. So many dentists automatically crown a tooth after root canal treatment. Insurance pays for it, and crowns are more profitable than fillings. But front teeth and molar teeth have different stress points. After root canal treatment, some dentists protect front teeth in other ways.
Root Canal Treatment – Front vs. Back Teeth
The anatomy and function of front teeth and molar teeth are different
Molar and Premolar Teeth
- Molar and premolar teeth chew and grind.
- Molar teeth have four cusps that can get pushed apart with the forces of grinding and chewing.
- Premolar teeth have two cusps.
- Front teeth don’t have cusps.
- Their function is to bite and tear.
- Horizontal stress affects front teeth—particularly the canine, or eye, tooth.
- Canine teeth have the longest roots and absorb horizontal stress to protect back teeth. The slope of canine teeth pushes back teeth part and relieves horizontal stress.
- The remaining front teeth absorb stress when you slide your lower jaw forward.
Is a Crown Required to Protect a Root Canal Tooth from Fracture?
Molar tooth – A crown or a ceramic onlay protects the chewing surface, absorbs vertical stress, and prevents the tooth from splitting.
Front tooth – Preparing the tooth for a dental crown will further weaken the tooth and make it challenging to absorb horizontal stress. Root canal treatment cleans out the pulp in the center of the tooth. When a dentist prepares a tooth for a crown, he reduces the diameter to almost 30 percent. Fifty percent or less of the normal fracture resistance is lost.
What about a titanium post?
Some dentists insert a titanium post through the center of the front tooth to prevent horizontal fracture. But post transfers stress to the bottom of the post and deep within the tooth. The risk of vertical fracture increases.
A crown on a front tooth after root canal treatment isn’t needed unless there is significant tooth structure missing. Some dentists use a crown on a front tooth if it turns dark after treatment from root canal filling materials and cement.
An Alternative to a Dental Crown After Root Canal Treatment
If much of a tooth’s healthy structure remains, after root canal treatment, a dentist can preserve it with the following steps:
- Clean the inside of the crown (above the gumline) of the tooth to remove root canal filling material and cement.
- Use a flexible white fiberglass post to strengthen the tooth and resist horizontal fracture without transferring vertical stress. Cement the fiberglass post.
- Fill the tooth with a durable dental composite.
- If the tooth begins to turn dark, cover the front with a porcelain veneer.
If you’re not comfortable with your dentist’s recommendation, you can schedule an appointment with an advanced cosmetic dentist for a second opinion. Eventually, you’ll need an examination and digital x-rays to assess the health of your canine tooth. If you need any treatment, the dentist will discuss your options for preserving the tooth and for sedation to help you relax.
David Finley, DDS of Monroe, LA sponsors this post. Dr. Finley is an award-winning cosmetic dentist who has achieved fellowship status with the American Academy of Cosmetic Dentistry.