This tends to be a more common problem than you would think. As a matter of fact, I would estimate that 20-25% of my business is from patients who need teeth retreated for one reason or another. The three basic reasons I can relate are:

1…a vertical-type fracture is present, in which case the tooth will probably be lost, but in rare cases can be salvaged for some time before loss occurs.

2…presence of nerve tissue retained in the canal network of the tooth. This can occur due to a missed (overlooked) canal or two. This is the most common reason. It also can occur when the tooth is not properly chemically cleaned and nerve tissue is left in the lateral canals of the tooth. This recurrence of infection will take years to return, making the patient think that the treatment doesn’t work.

Likewise, root canals that are not filled and sealed completely down to the end of the root can become problematic. Either you still have nerve tissue retained, or you have a process called “percolation” occurring. Because the canal or canals were filled short of the end of the root, blood leaks up into the hollow space in the canal between the filling and the end of the root, and dies. The body then reacts to the dead blood cells just as if it were dead nerve tissue, and over a period of time you get a recurrent infection.

3…if the tooth was restored inadequately, i.e. proper steps were not taken to seal the crown all the way around the tooth, leakage can occur. Saliva is laden with bacteria, and this can cause recurrent decay as well as leakage under the buildup into the canals.

All of the previous scenarios are due to the infiltration of bacteria and the ensuing immune response by your body. It is difficult to say how long all of this takes, but the average is 6 mo. to 3 years for retained nerve tissue. Leakage cases usually take longer to recur, 3-5 years is a fair estimate. I have seen cases that took 10 to 15 years to fail. It is really up to your own body as far as how long it will tolerate these conditions before letting you know.

• Why do I need endodontic therapy (root canal therapy)?
• What is a root canal anyway?
• Would you be more specific?
• How long does it take?
• Is the procedure painful?
• How come my regular dentist won’t do my root canal?
• Am I finished after the root canal? Do I need to have anything else done to my tooth?
• I had several crowns done in the past, how come I never had a root canal with those teeth?
• How long should I wait before having the buildup and crown done?
• Is it possible to not know that you need endodontic therapy?
• What is the difference between a regular dentist, and a specialist?
• Is it better to see a specialist, or let my general dentist treat me?
• What are some of the complications that could arise during treatment?
• Root canals don’t work on me! I’ve had several; and every time I end up getting the tooth pulled!
• I had endodontic therapy done 10 years ago. Last week I had another tooth treated, and the procedure seemed very different. Which one is better?