My dentist told me one of my molar fillings was cracked (I didn't know and had no pain), anyway because it had been a large filling, he said I would need a crown. He drilled away the filling and put a temp crown on last week. Now I have received an explanation of benefits from the insurance company and he charged for both a crown and then separately a core buildup. As far as I know there was not any core buildup done. I have questioned my dentist office about this, but so far no answer. Wouldn't I know if there was a crown build up done, doesn't it require him to put something in the tooth? He didn't, all he did was drill and then put on a temp crown. I have had other crowns and feel I would know if this was done.

A core build up is when the dentist rebuilds the tooth with filling material before doing the crown prep. It's a common procedure when a filling is cracked or there is not enough tooth surface to place a crown on.

http://www.vancouverdentist.com/pdfs/cro_cor_bui_up.pdf