Multiple CEREC Crown Failures, is Sirona or my Dentist responsible and what can or should be done?

In my opinion, non-metal crowns, whether CEREC or something else, tend not to last as long as precious metal containing ones. Sometimes people decide they don't want any metal in their mouth and opt for a non-metal crown, or they like the one visit convenience of CEREC. These are great reasons to get a non-metal crown, but I don't think patients always understand what they're actually getting. Metal free crown technology has greatly improved, but the reality today is still that at least for some people, having non-metal crowns will be more expensive in the long run.

Honestly almost 10 years is a decent time for the life of a crown. Many crowns last longer but even insurance companies will pay to replace a crown every 5-7 years. Sirona is the manufacturer of the machine that mills the crown they have no liability and do not provide the material for the crown. When a crown breaks it is usually only because of a few issues. First the dentist who placed the crown may not have provided adequate reduction to get the needed thickness for the material of the crown. This doesn't sound like it is the case because they would have failed much earlier than almost 10 years. The other issue is just normal wear and tear and habits of the patient. If you clench or grind your teeth you put more wear on the restoration. I see fractured natural teeth everyday, so if patients can fracture natural teeth they can definitely fracture a crown. CEREC is not too blame. When your new dentist places a crown there is a very good chance that the lab will be using a lab version of the CEREC machine to make your crown.

I would recommend discussing this with your dentist.  Cerec crowns can be made of many materials.  If they were done many years ago some of the stronger materials that we use today may not have been available.  I tell my patients that the only unbreakable crown is full gold.  If the patient desires a more cosmetically appealing tooth restoration there is a chance of breakage.  If the tooth is prepared properly and the correct material is used breakage is unusual.  Other factors like tooth grinding or chewing overly hard foods could cause failure. Dentists can't always be responsible for the way a patient treats their teeth anymore than a car dealer is if a customer abuses their car. I can tell you that Cerec would not be responsible for your broken crowns and it would be up to the discretion of your dentist.  With the current materials, if I had a patient whose crown broke I personally would replace it because I am confident the chance of breakage is minimal.

The Cerec technology is used world wide successfully so a failure is not the responsibility of Sirona.  All porcelain crowns such as these whether lab made or cerec made can fail, especially in the lower molar areas where the biting pressure is the greatest of any teeth.  The strength of the bite, whether habits such as clenching or grinding exist, the thickness of the restoration, etc. can have a great effect on longevity.  I have no way of knowing what material these were made of, but the materials available 10 years ago were not as strong as newer materials we have today such as emax or all zirconium crowns for posterior restorations such as yours, or an older technology such as gold or porcelain to metal.

The key to a successful CEREC crown is to have the crown 1.5mm thick at the thinnest part.  If it is thinner than that the risk of fracture goes us.  You also have to consider what you eat.  Eating very had things can break natural teeth as well as the ones we make.