How Common is It for a Molar to Break (Shatter) After Replacing a Filling?

Went in to have a very old and damaged ( there was a hole in it) filling replaced on my bottom L molar. After filling was completed and I was leaving the office I bit down and my a chunk of my tooth came out. Dds took pics and said there must have been a deep fracture he had not seen and that the tooth could not support the filling. I had to have a crown put on. Wouldn't it have shown on an X-ray? How common or likely is this to happen?? It was certainly terrifying.

Doctor Answers 4

Fractured Molar Filling

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It's not unusual at all for a molar with large fillings to fracture, sometimes repeatedly. Long term, a crown is the stronger, longer lasting choice in a situation like yours. People often choose to have a filling done instead because it's less expensive and quicker to do. Fractures or cracks can be difficult or even impossible to see on an x-ray, since they can be blocked by old metal fillings or simply in the same plane as the image.

Cleveland Dentist

Fractured tooth

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You preface your comment about your tooth saying the filling was old and damaged. Often times, fractures will not show up in an xray and most patients would rather pay for a filling than a crown.  Your doctor probably should have discussed a crown before placing the filling, if there was a likelihood of it failing. He is trying to do the right thing for you financially but, sometimes, it works out for the better in the long run to just say you need a crown because the tooth's structure is so compromised. The fractrure probably was not visible in the xrays .

Robert Fields, DDS
Van Nuys Dentist

Teeth can break after having fillings

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Hi, thanks for your post, and sorry to hear about your tooth, that's very frustrating.  With very large fillings, "full-coverage" restorations such as crowns or onlays are often recommended because once the existing filling/"bad" surrounding tooth structure is removed, the area that remains can be very large, wide, and fragile.  Placing another filling in the tooth does not provide the proper structure needed to withstand the forces of chewing/your teeth coming together (which is amazingly strong), which can cause the tooth to crack. 

How common is it for a molar to shatter?

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Very common most patient prefer filling over a crown but the more tooth that is missing or the larger the filling more likely it will fracture and the crown is the best option.  Good Luck



Kevin Coughlin DMD, MBA, MAGD     CEO Baystate Dental PC

Kevin Coughlin, DMD
Springfield 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.