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Dentistry/Cracked tooth -- Possible Crown


Hello Dr. Liewehr,

On my last check-up (23 Oct), I was told that my bottom left tooth ( I believe it is #18 or #19)  was cracked.  The crack is on the biting surface in one of the crevices.  I do not have any pain.  My dentist told me that if it begins to bother me I will need a crown.  When I asked if that also meant I would need a root canal, she said no.  My question is two-fold:  if it begins to hurt should I have a root canal?  Is it best to get the crown done before I have any problems?

Thank you,

Yes, I would. The pain is caused by a microscopic opening of the tooth when you bite on something. This allows fluid movement that causes a toothache sensation. The other cardinal sign is pain to cold, which accompanies the pain on biting because the cold causes fluid expansion (like when water freezes) also on a microscopic level. This fluid movement takes place in the dentinal tubules, the fluid in which is continuous with that in the pulp, or "nerve" inside the tooth. When the crack widens and deepens sufficiently, bacteria will enter the pulp, and it will necrose, or "die". In the meanwhile, the tooth will be overly sensitive to cold. Some dentists feel that if you just put a crown over the tooth, it will prevent this expansion of the crack and the fluid movement. Sometimes it works, but generally the tooth pulp is left in a chronically inflamed state, and the symptoms persist. The result is either permanent sensitivity, which can be quite severe, or necrosis and abscess. One way or the other, you will be better off having the root canal therapy, which will prevent or cure both problems, before your crown is placed. After it is placed, the endodontic therapy can still be performed, but it will necessitate drilling a hole through your new crown.


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Frederick R. Liewehr DDS, MS, FICD


I can answer your questions about root canal therapy in general. PLEASE DO NOT ask me to diagnose your particular problems or recommend treatment as I cannot do this without examining you and seeing your x-rays.


I am a Board-certified endodontist, former university department Chairman, teach dental residents, and have a private practice.


J of Endodontics, Endodontics and Dental Traumatology, O,O,O, Military Medicine, Medical Bulletin, J of Dental Education

DDS, MS (Oral Biology), certificate in Endodontics

Awards and Honors
Surgeon General's "A" Designator, Fellowship ICD, Order of Military Medical Merit

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