I had an emergency dental appointment for a toothache on my top right first molar. The dentist scheduled a root canal for me. But he also looked at my left incisor and noticed that the tooth was a little dark. I told him that I had a root canal on that tooth in 1986. The only reason I remember the year is because it was a month before I got married. The dentist recommended doing a dental crown on that tooth to prevent it from breaking. I do not feel any tooth pain. Is a dental crown necessary? – Karson from GA

 

Karson,

Thank you for submitting your question to our office.

Whenever you have a lingering toothache, it is wise to see a dentist promptly. But do not agree to let the dentist complete cosmetic work without verifying if he or she has advanced cosmetic dentistry training.

Although root canal treatment can make a tooth weak and at risk for breaking, not every dentist automatically places a crown over the tooth. But the condition and location of a tooth can determine if it is wise to get a crown.

Stress on Molar Teeth

The stress on molar pushes the four cusps—or peaks in the biting surface—apart. Premolars have two cusps. And stress can cause them to split also.

Stress on Front Teeth

Front teeth are subject to horizontal stress. Canine teeth have long roots to absorb some of the lateral pressure on back teeth. When you chew and grind food with your back teeth, the canine tooth forces the back teeth apart to relieve stress.

Protecting a Root Canal Tooth

• Back tooth – A dentist can protect a back root canal tooth from fracture by covering it with a dental crown or an onlay. An onlay covers a tooth’s chewing surface and at least one cusp, or tooth point.
• Front tooth – Although root canal treatment weakens a front tooth, preparing it for a dental crown will further weaken it. A dentist prepares a tooth for a crown by removing about one millimeter of tooth structure on every side of the crown. A tooth can be left with 50% or less of its initial fracture resistance.

When little healthy tooth structure is left, a dentist may use a crown to protect a front tooth. Otherwise, a crown will only weaken the tooth.

Some advanced cosmetic dentists use this technique:

• Clean out the crown of the tooth, removing root canal filler material and cement
• Insert a flexible fiberglass post deep into the tooth
• Cement the post
• Fill the tooth with durable composite
• Bond a custom porcelain veneer to the front of the tooth

 

We recommend scheduling a consultation with a cosmetic dentist to examine your tooth and explain your options.

 

Ryan Perry, DDS of Baton Rouge, sponsors this post.