Expert: Mark Bornfeld DDS - 3/9/2007

Question
Thank you Dr. Bornfeld.  and Yes you are correct the #20 was determined to be the necrotic tooth.  But the first endo felt that my cold sensitivity was a coincidence with finding the dead tooth (in the same tooth/area)? Which I did not understand.  What you said about the lesion makes sense and I have read that the lesion is of utmost importance but this endo insisted  that my very small lesion was NOT the reason for recommending root canal.  He claimed it was solely due to his experience with the nerve vitality testing being negative in my tooth.  Its been 2 weeks since I have seen him and the tooth is now a little bit sore when I eat sometimes only since the 2nd endo visit last Friday's manipulations. It was not sore before the second visit or at any other time that I was aware of.

From your explantion which makes sense. It seems to me that there is no way to know for sure if you are deeling with a dead tooth. And harder to make an educated guess without even a cavity in the tooth.  What would you do? Drill away?  Cant inflammation go away as with other areas of the body.  I asked the second endo to point out the lesion to me  (since the first endo never even mentioned it to me except when I called him to clarify what exactly he found wrong on the xray to want to do a root canal) the second endo mentioned that there were small lesions on adjacent teeth and that alone did not have to mean anything.  Interestingly enough I went to an acupuncture treatment that left me feeling extra sore on my right TMJ and sensitive to cold water when I got home on my right molar.  I also felt my molar in the right back tooth was sore. This lasted only for a day or two (fading substantially)  This was the only time I left with episodes of stabbing pain in my right TMJ (I am not sure if this is normal- though the Doctor of Chinese Medicine says that it means that it is working-- please let me know if this is supposed to happen?? Or if anyone has any info on this please email me.)

I guess my point being that it seem the nerves really can act crazy. I wish there was I way to know before just drilling a hole in my tooth at the first sign of a problem.

Thank you so much for your time and knowledge!!
Best,
Emma
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The text above is a follow-up to ...

-----Question-----
Is it possible to need a root canal when you have an xray which shows no sign of a cavity or pockets or anything wrong, no trauma?  I had my braces tightened on my upper teeth and suddenly had extreme sensitivity to cold for a week which localized to one tooth, lower left #20, the lower braces have not been tightened in over 6 months and had no other symptoms and it went away after a week.  I saw 2 endodontists.  The first endo found #20 was the extremely sensitve tooth to cold but also said that the cold sensitvity is unrelated to the dead tooth although its in the same tooth/area?? His nerve conductivity test found the #20 to be necrotic.  How can it be dead and be extremely sensitive too? Only when I called him the next day to clarify that he found nothing on the xray did he mention there was a very small lesion at the end of the root, but this was NOT the reason he recommended doing a root canal.  He said it was soley due to the electrical testing which was negative.  The second endodontist found the #20 tooth had very delayed sensation to cold around 20 seconds. Both endos found palpation tests where sensitve.  

Its been almost two weeks now and my tooth is not sensitive to cold anymore it might be a little sore from the second endo manipulation but I have TMJ and the visit gave my a migraine, regardless.

Please help shed some light on this. It is very confusing.
Thanks,
Emma
-----Answer-----
Dear Emma,

I wish you could clarify something so that I can consider this further. You said that the endodontist found #20 was (past tense) the extremely sensitive tooth, presumably the tooth whose sensitivity went away a week after the tightening of your orthodontic appliance. You then say that, according to the endodontist, the cold sensitivity is unrelated to the dead (necrotic) tooth, which was determined to be #20. Is #20 the "dead" tooth, and if so, how can it be unrelated to the sensitive tooth?

In any event, the finding of a lesion at the root apex makes any other argument irrelevant, since this is objective evidence of an infection. Sensitivity may manifest in a vital tooth (self-evident, since pain sensation is conveyed by a vital nerve); it may also manifest in a degenerating pulp as long as there remains some vital pulp tissue. However, a totally necrotic tooth can still be sensitive-- or more accurately, it is the inflammation in the supporting bone that manifests sensitivity; the bone is richly supplied with sensory nerves.

Keep in mind that the diagnostic tools that dentists use are not foolproof; there are infections that evade detection by direct visualization, by x-ray, and by symptomatology. As such, the failure to detect infection in a tooth is not sufficient to unequivocally rule it out. This is one source of confusion, and may often lead to the paradoxical finding of infection despite clean diagnostic symptoms and signs. It is not a paradox, but simply points out the limitations of the diagnostic process.

Hope this helps...

Mark Bornfeld DDS
www.dentaltwins.com
Brooklyn, NY

Answer
Dear Emma,

A finding on x-ray of a radiolucent lesion at the root tip, combined with a failure to respond to an electric pulp test, is sufficient reason to conclude that the pulp is necrotic. Dead tissue will not revive, and will almost always result in more conspicuous infection in the future. Whether your doctors can detect a reason for pulpal necrosis is more of academic than clinical interest; regardless of the cause, it is appropriate to perform root canal therapy, and it is no longer guesswork once pulpal necrosis has been determined.

I cannot advise you regarding your response to your session of Chinese Medicine, since I am not knowledgeable about this type of treatment.

Mark Bornfeld DDS