I had a CEREC crown placed. However, it has come out several times within the last year. Finally, after the fourth time, I consulted a different dentist, who replaced the crown with a zirconia porcelain crown, but it, too, has come out several times. The dentist suggested a full porcelain crown, stating that the cement is adhering to my tooth, but not the crown. He indicated that the all-porcelain crown is rough of the underneath and would, therefore, bond to the cement more effectively. I’m unsure of what my next step should be, but I am tired of the trouble these crowns have caused. What do you suggest I do?
The CEREC crown, or same-day crown, is created by a computer in the dental office, the day of your appointment. When prepared and adhesed correctly, the crown will remain permanently affixed to the tooth. The material of which your crown is made is not indicative of how permanent the bond will be. Whether your crown is porcelain, gold, CEREC, or zirconia, all are made to stay permanently.
However, there are two factors that can determine if a crown will stay on permanently or not. They are the bonding strength of the cement, and the shape of the prepared tooth. The most important of these is the shape. If the tooth is prepared with little taper, a crown can be adhered with a weak cement, and it will stay permanently affixed. However, if there is a lot of taper, even some of the strongest cements will have difficulty staying on.
This is not implying that getting a solid bond between the crown and tooth would not solve your problem. The cement’s strength is important. But, when a tooth is prepared with good retention form, the crown will not fall off multiple times in one year. This indicates that your tooth may have been prepared with retention form that is insufficient.
To move forward, it would be a good idea to consult a dentist experienced in placing crowns that will stay on.
This article was brought to you by Gilbert CEREC Crown provider, Dr. Matthew Roper.