Why did my Cerac crown come off? (Photo)

Hello there, I'm sorry that this happened to you, but here's my opinion.I don't want to speculate on another dentist's choice to put a crown on a tooth that looks like yours without first placing a post, but I can tell you that it is my usual practice to place a post and then build-up, before placing the crown.  I am not a big fan of the Cerac crowns, but they are fast and convenient.  I usually place zirconia crowns made by a lab to create my perfect crowns.  Sometimes, if the Cerac crown has margin issues, this can cause the crown to come off.  And one last possibility is that the glue used to cement the crown was defective.  I don't know how long you have had the crown 1, 2, 5 years and what is your dentist's policy on guarantee of his work.  Most dentists will guarantee their crowns for a couple of years.  My policy is 10 years, but I require that the people get their teeth cleaned every 6 months and maintain good dental hygiene.  Hope everything works out for you.  Good luck.

It most likely failed because there was inadequate tooth structure to hold the bonded Cerac restoration onto your tooth.  There is a lot of pressure when chewing on back molars!Without knowing what the tooth looked like before the preparation I could not tell you if it was prepared properly or not. It appears that even though you had a crown, it wasn't a "full crown" that covered the entire tooth down to and below the gums.  Your dentist obviously was trying to be conservative (a good thing!), and not prepare your tooth unnecessarily.  However, you would probably have much more success and the crown would have much more retention if the tooth was prepared down to and below the gums.  Retention is a function of surface area bonded, and the the more the tooth is covered and bonded with the new restoration the more likely it will be long term successful.

Hard to know for sure based just on the xrays you sent.  A couple of possibilities looking at the prep is there is inadequate tooth structure to retain the restoration and a build up is needed along with a new restoration.  Or possibly some of the tooth structure that was retaining the crown broke off inside the restoration allowing it to come off.