Dentistry/root canal


hello dr robert,

I had root canal on my lower 2nd dentist said I don't need a crown now that my tooth is still strong... am still having pain on the tooth so I might still need to do another root canal on the same tooth...
my question is ..if I did second time root canal on the same tooth...will the tooth be more fragile to break after second time root canal?

Thank you

Dear Jill,
Thank you for your question. Post operative pain sometimes does occur after root canal treatment.
The comments and opinion I am expressing is made without the benefit of a clinical and radiographic exam.
Several issues are raised by your question which I am going to attempt to answer.
When a patient has postoperative discomfort after root canal therapy, one has to attempt to decipher the cause. What was the condition of the tooth before treatment. Was there bone loss and inflammation and or infection present in the bone or tissues. This is quite important since a periapical(area around the roots of the tooth in the bone)may contain pus or infection.There could be a cystic lesion that is asymptomatic and present, but as soon as root canal treatment is performed , bacteria and inflammation occur and fluid builds up in the bone and raises the tooth in the socket. Thus when a patient bites down, pain may occur. The constant biting or chewing on the tooth that is high in the bite needs to be reduced or pain will persist. This condition is the most common cause of post operative root canal pain.
Usually Occlusal adjustment(reducing the bite), prescribing anti-inflammatory agents , analgesics and possibly antibiotics usually resolves the problem. Once the symptoms are gone, a crown should be placed on the tooth. Full crown coverage is recommended for posterior teeth that have had root canal treatment.
Other considerations for the persistent cause of pain after root canal treatment are, missed canals, inadequate instrumentation and debridement, incomplete obturation-filling or overfilling the root canal and possible microcracks or fractures.
Conventional retreatment, redoing the root canal is a viable procedure and may be indicated under certain circumstances. Some of the issues I listed above may be indications.
If the pain persists after root canal retreatment, surgical intervention can be performed to save the tooth.
In rare occasions in mandibular second molars the root apices can lay on top of the inferior alveolar nerve.Sometimes with root canal treatment this nerve can be irritated and cause pain and parathesia(numbness). This is the nerve trunk that innervates the entire mandible.(This is what is anesthetized when they give you a shot or block on the lower jaw)
In answer to part of your question, root canal therapy can be redone. Depending on the root anatomy and the type of initial treatment the root may or may not be weakened. If canals have to be enlarged the more internal root structure removed could weaken the tooth.If the canals are curved and tortuous care must be taken not to over instrument the canals and weaken or perforate a root.
My suggestion is to find an endodontist who would easily be able to assess your problem and provide treatment options. If there is a dental school near you, there would be faculty trained in this specialty that could assist you.
Good luck with your care and I hope you are able to relieve your discomfort with proper treatment. I also want to mention that I answered your question within 2 days but apparently it did not register through the system , I sorry for the delay.


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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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