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Dentistry/cavity extending below gum line


tooth #21
tooth #21  
How are you, Dr. Block,
I came to my dentist to recement the crown which fell from the tooth #21 after 15 years.  She looked at this tooth, x-ray, and said that tooth is a goner because cavity at tooth neck extended under the gum and surrounded nerve. She said she can't touch and clean that cavity because it will be a root canal. The dentist put crown back on permanent cement and advised me to extract it when I will start having pain from infected nerve. Is it possible/practicable first to make a preventive root canal and then to remove that cavity under the gum? Thank you very much for your opinion!

Good Day,
Thank you for submitting this question.Your clinical situation is not all that unusual.Of course my comments are based solely on the information you have provided without the benefit of a clinical or radiographic exam.
The short answer to your question is yes.
However the following is a more thorough explanation.
It is not all that unusual that recurrent decay can develop under and around a pre-existing crown.When this occurs, as in your situation, the dentist must access the periodontal(gum)and bone support around the tooth.All the decay needs to be totally removed, and the strength, quality and amount of remaining healthy tooth and root structure needs to be evaluated.A treatment plan with the various alternatives can be formulated.
In your particular situation it sounds like the amount decay that needs to be removed will not only result in the pulp( the gelatinous tissue of the root that contains nerves and blood vessels- the root canal space)being exposed, but the remaining healthy root structure below the gum and possibly the surrounding bone. Thus the real key to treatment of your situation is the periodontal(gum)and supporting bone structure around the remaining healty root after the decay is removed.
After all this decay is removed a root canal canal be performed.This will resolve your acute pain. After this treatment,a crown lengthening procedure can be performed to surgically trim the bone and gums. Once this is accomplished, there will be adequate healthy root support for a post, core and crown. A root canal should be performed before this is attempted.There are some additional considerations before performing a crown lengthening procedure. These include your overall periodontal{gum and bone status), length and width of the remaining root for restorative considerations.
Other treatment alternatives could include tooth extraction and placement of a fixed bridge, or an implant. Your dentist should review all these alternatives with you. This is important before beginning any treatment.My recommendation is to seek out a trained for Endodontist(root canal specialist) and Periodontist ( gum specialist)to evaluate your particular situation. They would be best able to provide treatment for your particular situation.If you proceed with all these procedures, they may even recommend a Prosthodontist( specialist in advanced restorative procedures).If you are unable to locate these specialists' where you live, you could try to go to a dental school for care. There are faculty in each of these trained areas that could give you the best advice.Good luck with your 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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