Expert: Mark Bornfeld DDS - 3/7/2007

Question
Several months ago I experienced a fractured cusp on a lower molar which had previously filled (20+ years ago) My dentist cleaned out decay under old filling and refilled the tooth. He mentioned that since it was a large cavity and the structure was compromised the tooth would require a crown in the future.  My question is this, as he has already filled the tooth, would that filling act as a core for the crown or does that material have to be removed and a different material used before crowning the tooth.  

Answer
Dear Nancy,

There are no hard and fast rules that apply here. Although the removal of all prior fillings allows for better inspection of the tooth so that complete removal of decay can be assured, there is also some risk if the filling is deep that taking out the filling might risk injury to the dental pulp (nerve).

Regardless of whether the prior filling(s) in a tooth are intentionally removed, they often fall out in the course of mechanically preparing the tooth for a crown. If this happens, the dentist must use his discretion regarding whether a core needs to be placed, using any material of his choosing. If the previous filling does not fall out in the process of crown preparation, is well-retained by the tooth, and the removal of all tooth decay can be assured despite the continued presence of the previous filling, there is nothing wrong with allowing the old filling to serve as a core.

Hope this helps...

Mark Bornfeld DDS
www.dentaltwins.com
Brooklyn, NY