New Crown Replacement: Decay Under Existing Crown Margin

A typical crown can last a long time; however, there are some situations that a crown needs to be replaced by a new crown and one of the common reasons is decay.  Crown is typically placed to protect the weakened tooth.  Even though the tooth is covered by the crown, the tooth still needs to be cleaned and brushed just like any other tooth in the mouth.  If there is inadequate oral hygiene, bacteria can cause tooth decay under the existing crown.  Initially this tooth cavity goes undetected because it does not cause any symptoms.  The patient may not feel any pain until the tooth cavity has gotten bigger.

One way to prevent this from happening is to have a periodic dental checkup by a dentist.  I would periodically take xray images when patient comes in for checkup and cleaning visit.  The xray images would reveal if there is any cavity in between the teeth.  For example, the following xray image shows that the tooth #15 has a large cavity under the crown margin of an existing crown.  The crown margin is the interface between the crown and the tooth structure under the crown.  Often food can get stuck in between the tooth and decay develops at the margin of the crown.


Recurrent Decay under existing crown margin

Xray image shows decay under existing crown.

I recommend to patient that the tooth needs a new crown replacement.  Also I would recommend better oral hygiene and encourage patient to use dental floss to clean out food in between teeth.  I also advise periodic dental checkup and cleaning.



Written by Daniel Tee, DDS, MS

Dental Office in Tempe AZ

Serving the city of Tempe, Chandler, Phoenix, Gilbert, and Mesa in Arizona.  Practicing General Dentist