Expert: Steven C. Scherr, D.D.S. - 12/30/2006

Question
Thx very much for the detailed answer.

If I had #2 I'd extract 3 in a heartbeat.  However, I don't and taking 3 has my endo recommending a sinus life and subsequent 1 or 2 implants.  I'd rather not.

I had a teaching dentist say he's seen a similar situation in a patient that had a large restoration on the tooth under the crown.  He said this went away after redoing this.

I too have a large restoration under the crown.  I have asked him a followup but do not have an answer yet that maybe you can comment on.  WHY would that effect anything?

Finally - while I know it is not the prime location for one - COULD a cantilever be done off of 4 & 5 in lieu of the implants?

THX again!
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The text above is a follow-up to ...

-----Question-----
Have there been any recent advances in locating accessory canals specifically in a tooth that is calcified?  How about a crack?  I have numerous digital and standard x-rays over the past 3 years of #3.  No crack is ever evident.  It is calcified.  After RCT in august I've developed some chewing pain on it as well as some cold sensitivity.

I know even a poorly done root canal would stop cold...

Therapy was done by an eminent endodontist aided by a microscope.

He and my DDS both think it looks clean and well done.  It has a large restoration on it under the 5 year old crown.  We've basically taken it out of occlusion.

So - does the microscope help determine cracks and accessory canals?

THX
-----Answer-----
Bob,

The nerve channel system within a tooth is much more complex than earlier thought.  It often has numerous side passages, narrow flutes, and blind turns that cannot always be fully identified or navigated even by the most proficient endodontist.  Fortunately, cleaning out the gross majority of the nerve channel is effective 90% of the time.  Unfortunately, missed nerve debris is capable of causing symptoms, including cold sensitivity, in a small percentage of treated teeth.

Cracks are very difficult, and sometimes impossible, to locate because they often occur in hidden areas of the tooth.  Cracks that develop between the teeth or beneath the gum line are easily missed, and they rarely show up on xray.  Microscopic examination helps find some cracks that would have been missed otherwise.  However, other cracks are located out of viewing range of the microscope.

Sounds like you are in good hands.  Dentistry just isn't perfect yet.  Bob, hang in there.

Steve

Answer
Bob,

I agree with you that there is little likelihood that merely replacing a filling would solve the pain issue.  The only exception to this involves a filling that extends beneath the gum line and touches the gums.  In the latter situation, potential defects or gaps at the edge of the filling could harbor bacteria that could be a potential source of pain or sensitivity.  Having said this however, I nearly always remove all fillings in a tooth before making a new crown.  I do this to insure that there is no undiscovered decay beneath an old filling that might later compromise the tooth's integrity.

If there is a crack or residual nerve debris in the tooth, and this is the cause of the discomfort, removal of the tooth will eliminate the sensitivity.  However, there are other possible causes of this type of pain.  The nerve inside a tooth is really just the terminal end of a much longer nerve.  Whenever a nerve becomes severed, it sprouts numerous new fingers from the cut ends  These fingers extend outward in an effort to locate the other side of the severed nerve.  If the ends find each other, healing and reattachment can take place.  If the ends cannot connect, the ends tend to degenerate.  In some cases, the fingers on the cut end of the nerve will ball up and produce a neuroma.  A neuroma may produce sensations of pain that the brain interprets as coming from the original nerve terminal.  If that original nerve terminal had ended in a tooth, and the nerve was severed where it enters the tooth via root canal therapy, there is a potential for neuroma formation.  Neuromas are uncommon.  However, they can produce the type of symptoms you describe.  There is no test available to detect a neuroma.  They are important though, because the pain from a neuroma will persist even after the tooth is removed unless the neuroma inadvertently comes out with the tooth.

There are other uncommon disorders that can refer pain to the teeth.  These are referral forms of muscle pain (Myofacial Pain Syndrome), a migraine-like disorder (Atypical Odontalgia), and various nerve disorders (neuralgia).  In each of these cases, removal of the tooth either does not eliminate the pain, or only temporarily eliminates the pain.  The pain often shifts to an adjacent tooth.  It is very sad to see a whole row of teeth having been removed one by one in an effort to get rid of the pain.  These disorders are treatable, but tooth removal is not the answer.

Bob, I tell you about these things for the sake of completeness.  It is more likely that your problem really is due to residual nerve debris or a crack as earlier discussed.  I want you to be aware of these other possibilities in the event tooth removal does not solve the problem.  If that should occur, do not let anyone continue to remove successive teeth in an effort to eradicate the problem.

As to your question about replacement teeth, implants are absolutely the best solution.  If you are adverse to this, you would need to consult with your treating dentist about the quality of support available for a cantilever bridge.  Since you are replacing a molar, as many as 3 support teeth may be needed to withstand the biting pressure on the cantilevered false tooth.  Each situation is different.  Your dentist can help you with this decision.

Bob, have a happy New Year!

Steve