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Dentistry/Root Canal - Hypersensitive adjacent tooth


Dear Dr.

I am 28 years old and pretty healthy overall. About a month and a half ago I had a root canal performed by my dentist on one of my molars (#14).  The root was *not* infected, but there was decay that was too close to the root for a traditional deep filling. The procedure was fine and my tooth was filled and okay afterward.

I needed to wait about a month for the temporary, and then permanent crown, due to my own schedule, however.

After the permanent porcelain crown was placed, I experienced searing pain to cold and hot liquids.  This then calmed down -- and is now only sensitive to cold liquids.  The pain is quick, and short, but goes away as soon as the source of the cold is removed.

I've sought several opinions on this.  The endodontist yesterday did a cold test, which he determined that the tooth adjacent to the recently treated tooth is the one causing me pain. He said that sometimes when a tooth goes through trauma like this, the ones around it can become hypersensitive. This makes sense, and I am assuming will heal. It is already getting better.

With that said, after looking at the x-rays, (the 3d kind where it takes an image that looks like a cross-section of your tooth), he stated with 'almost certainty' that it looks like there is a 4th canal that remained untreated in my tooth.  He recommended a re-treatment of the tooth.

So that brings me to my questions:

Is this absolutely necessary? If the canal is too small to see on a traditional digital x-ray, is re-treatment necessary?  What complications could result if it is not treated/filled? Also, is it really necessary to re-do the entire root canal, or can just that one canal be filled? Are there pro's and con's to each of these methods?

I plan to discuss with my dentist who did the original procedure, but she is away today, and I would like to have as much knowledge about this as possible to settle that unsettled nagging in my mind.

Many thanks,

Hi Katrina,
Sorry about your recent dental issues.  I agree with your Endodontist's recommendations. The adjacent tooth should improve with time and the hypersensitivity is either due to trauma to the tooth or gingival (gum) tissue.  

If a 4th canal remains untreated, that space will harbor bacteria. With time, you could develop a localized dental infection with pain, swelling, etc.  It's always better to catch these things when the tooth is not hurting.

I suggest you move forward with the retreatment after discussing the treatment plan with your general dentist.

Hope this helps,
KG Amin, DMD
Austin, Texas


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Ketan Amin, DMD


Graduating from Harvard School of Dental Medicine, I received a broad understanding of both medicine and dentistry. I continued my training at New York University, as a dental specialist in endodontics, which concerns root canal therapy, related surgeries, as well as diagnosing and managing various forms of pain occurring in the head and neck


Dentistry; Specialist in Endodontics (Root Canal Therapy).

American Association of Endodontics American Dental Association American Academy of OroFacial Pain

Harvard School of Dental Medicine-Doctorate in Dental Medicine (DMD) New York University College of Dentistry-Certificate, Endodontics

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