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Dentistry/root canal on crowned tooth


Hi Robert,
I had a back molar tooth crowned 9 months ago as I had biting pain and my dentist recommended the crown as the best option.  All was fine until recently when I suddenly started having slight pain when biting on this tooth.  I had also chipped my front tooth slightly and so my dentist concluded both problems were indicative of me grinding my teeth at night (which he plans to fit a night guard).

However, the biting pain on the crowned tooth is still not resolved.  I've already sought a second opinion from another dentist.  I asked about having a root canal.  She said this was possible but there was a chance of the tooth being cracked (from within the tooth) but this would only be known when the root canal was being performed and if there was indeed a crack then the only option would be to extract the tooth.

Could you possibly tell me what the chances are of a crack being found during a root canal procedure?  Would it be more likely if I was experiencing slight biting pain?  Also, is there no way of visualising the inner tooth to tell if it's suitable for a root canal?

Thanks for any advice you can give.


Thank you for your question. As always, I state that without a full clinical and radiographic exam, it is really impossible to ascertain a precise diagnosis and treatment plan.
However, your chief complaint and history are very common complaints when a tooth needs endodontic (root canal) therapy.
As your dentist stated, a person may experience biting pressure if they have a crown that is " too high" in the bite or does not occlude properly. His recommendation to check your bite occlusion and evaluate your potential for Bruxing( grinding) is completely reasonable.
However, with your history of discomfort on the posterior tooth before the crown was placed, and now with discomfort to biting, it is very likely that you need root canal therapy.

As a way of understanding the process with your history I will review briefly the etiology of why you may experience these recurrent signs and symptoms. Inside the roots of a tooth is a collagenous gel called the pulp. It contains nerves and blood vessels. When you have decay, subsequent fillings, before the crown was done , these internal components are traumatized  and damaged. Many times the body repairs this and a patient develops no pathology or clinical symptoms. However, when a crown is placed the tooth is reduced to a large extent to fit the new crown. This process further damages and traumatizes the internal tissues in the roots. As a result, the patient demonstrates pain, to hot and cold, biting pressure or in some cases may develop swelling or a clinical abscess. In your case the biting pressure indicates that their is now irreversible damage around the end of the roots and inflammation is occurring in the tissues and bone that encapsulate your tooth. Thus it hurts to bite down. When the crown was initially placed you may have had very mild biting symptoms that were really diagnostically undetectable. After 9 months of chewing, the damage inside the tooth has gotten worse and as a result, you have developed inflammation in the tissue and bone around your roots with more severe biting pressure.
Its important to understand the process because from your history you do not exhibit the signs or symptoms of a vertical root fracture which would indicate removal of the tooth.
The best way to visualize any potential internal crown fracture is during root canal therapy. With high magnification and lighting, many micro cracks and fractures are identifiable.
Once root canal therapy is begun, these can usually be identified. If you had a large amalgam (silver filling) in this tooth before it was crowned, it is not unusual to visualize crazing and mirco cracks that enter the pulp chamber within the crown of the tooth. If these do not extend into the root structure, the prognosis is usually quite good with endodontic therapy.
If these microcracks are present and they extend further down into the root structure the prognosis with root canal therapy is reduced. Thus the greater the extent, length and size of the crack determines the  prognosis.
There are 2 recommendations I would suggest.
First seek the care of an Endodontist( a specialist in root canals). The standard today is utilizing magnification and LED lighting during treatment. This gives you the best opportunity to determine your diagnosis and prognosis. If there is no Endodontic specialist near you, I would seek out a dental school and try to have a faculty member who is an Endodontist evaluate you.
My second suggestion would be, once you seek this specialist care, ask them about the use of a Cone Beam Scan to visualize the three dimensional anatomy of your tooth. Sometimes this instrument may be able to detect a micro root crack that can be diagnosed before Endodontic treatment has commenced. Its best to let the Endodontic specialist after examining you make this determination.
Good luck with your care and treatment.  


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robert block


I would prefer to answer questions related in my specialty of Endodontics( ROOT CANAL THERAPY) I am a Board Certified Endodontist with a special interest in advanced surgical endodontic procedures. I know root canals create a lot of apprehension in patients, and they usually have many questions about the procedure. I can address patient concerns either before or after their root canal treatment. I also have re-treated numerous patients who have had previous endodontic treatment. As a result of these clinical failures,and the increase in the use of dental implants, its important patients understand the alternatives of therapy. There are often many components to treatment that interrelate the disciplines of endodontics, periodontics and restorative dentistry.Patients frequently question the importance of considering all facets in a clinical regimen. Hopefully, I would be able to educate and contribute some information from the endodontic perspective.


Diplomate American Board of Endodontics, 35 years plus private practice experience. Formerly Professor and Chairman, Department of Endodontics at US dental school. Editorial journal reviewer for the endodontic section of The Journal of American Dental Association. Serve as a reviewer on several editorial boards.

American Association of Endodontists, College of Diplomates, American Board of Endodontics

Over 150 publications, abstracts, case reports, chapters in textbooks. J. Dental Research, J. of Endodontics, J. of Oral Surgery Oral Medicine Oral Pathology,The NEXTDDS J.For example: The Single File Approach for Predictable Endodontic Canal Instrumentation:The Wave One, THE NEXTDDS J. 4-2:13-17 Fall 2014 Non Surgical Management of an Endodontic Failure Utilizing Contemporary Technology, www.THENEXTDDS 5-1:60-63 Spring 2015 Are You Still Using Formocresol? An Update, Tn. Dent. J. 89-4:14-19 Fall 2009 Management of Endodontic Failures, Oral Surg.vol.66:711-Dec.1988

BA. DePauw University, DDS. University of Michigan, MS. Medical College of Virginia, Virginia Commonwealth University, Gen. Practice Resident, University of Connecticut, Endodontic Resident Medical College of Virginia, Virginia Commonwealth University

Awards and Honors
Numerous Awards and Honors, Edward P. Hatton Award( Int. Assoc. of Dental Research), Endodontic Memorial Research Award ( American Association of Endodontics) Outstanding Endodontic Department Teaching Award (given by dental students)Fellow American Academy of Dental Science

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