Is it normal for a brand new crown (not yet attached to tooth) to break when asked to bite down on it?

I had a root canal on a molar done by specialist. Then my dentist prepared the tooth for a crown. When he put the crown on the tooth and told me to bite down hard... I did....when he asked me to bite down hard a second time, the new crown broke in half. Is this normal? How can it last if it is so easily broken? Is my dentist doing so getting wrong?

Doctor Answers 2

Breaking a new crown when trying it in

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Hi Edwina,

So sorry to hear that your crown broke when your dentist was trying it in. The fact that you said that it broke in half tells me that the crown was most likely an all ceramic/porcelain crown. This type of crown does not obtain its full strength until it is fully bonded onto the tooth, and is subject to fracture up until that point. Most likely the crown was high in occlusion (its bite), or was not seated properly, and the compression force cracked it. In addition, crowns need to be of a certain thickness to prevent fracture. If the dentist did not reduce the height of the tooth enough during the preparation, before the impression, then the ceramic would be too thin, and it would fracture. So, as you can see there are multiple reasons the crown can fracture, and it may, or may not be something that your dentist has done. I would give them another chance to remake the crown, and I am sure you will have a crown that will last you a very long time. Best of luck. 

Manhattan Dentist

New Crown Breaking

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Was the crown a permanent crown or a temporary crown?

Temporary crowns are acrylic, if it is to thin, can crack easily.  

If the crown is a permanent crown, cracking of the porcelain is not normal during insertion.  However, certain factors could have caused the crown porcelain to crack:

1.  Imperfection or impurity in the porcelain which caused a weak area.  

2.  Inadequate reduction of tooth resulting in a thin area of porcelain and weak spot.  If this is the cause your dentist must reprep the tooth to provide adequate room and thickness of porcelain.  

David M. Schertzer, DDS
Saint Louis Dentist

These answers are for educational purposes and should not be relied upon as a substitute for medical advice you may receive from your physician. If you have a medical emergency, please call 911. These answers do not constitute or initiate a patient/doctor relationship.