How do I get a cavity under my crown? How long does a crown last?

I replace crowns many times a month due to decay. I probably get asked how a crown “gets decay” on it about 25% of the time. This is a very reasonable question if you are not familiar with the actual process and design of a crown cemented to a tooth.

First, a crown does not get a cavity. The cavity starts on the root at the crown/tooth junction. That is why you must still floss and brush crowns as good or better than you brush your teeth.

Second, any tooth structure can get decay regardless of your age. I do fillings on 70, 80 and 90 year olds all the time. In fact, as we age, our dexterity decreases so our ability to clean the root decreases therefore decay is a natural result.

Third, as the tooth approaches the gums and its diameter decreases. That means that the nerve is closer to the outside surface of the tooth. So, a small cavity may be 6 mm from a nerve on top of a tooth, it may be only 2 mm away from the nerve on the root of a tooth.

The location of the cavity under a crown will dictate the treatment for the tooth. If the cavity is on the outside near the cheeks, it may be able to be patched and not remake the entire crown at this point. If it is in between then the crown and adjacent tooth, the crown should definitely be replaced.

Have your dentist take intraoral photos to show and explain where the decay is located. Don’t forget that it’s better to have weaker teeth and be a fanatical cleaner than to have great teeth that you don’t take care of.

Crowns typically last between 5 and 20 years. Some crows may fail sooner and some may last longer. The longevity of a crown depends on several factors.

  1. How often the patient brushes and flosses well.
  2. How often the patient gets a dental cleaning.
  3. How large the microgaps are and the cement used to fixate the crown to the tooth.
  4. How much load is applied to the tooth. Grinders and bruxers get less time due to excessive force over long periods of time.
  5. And how much tooth structure remains under the crown to hold it in place.

Click here if you want to read more about dental crowns.

If a patient waits too long before crowning a tooth then more tooth structure will be lost as additional fillings are placed.  Ask your dentist if they will still have enough tooth structure to crown in the future.

Call Smile Solutions by Emmi Dental for more information at Smile Solutions by Emmi Dental office Phone Number 302-999-8113.

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