Although with proper restoration and good oral hygiene the success rate for root canal therapy is very high (reported to be 95% or better), failure does occur.  Occasionally, a tooth will continue to be uncomfortable or the healing that was expected might not take place.  This could be due to significant cracks, complicated anatomy or severely calcified canals.  Other times a treatment will be completely successful and later become contaminated by deep decay, leakage of saliva through a cracked filling, or because the patient did not return to their dentist for final restoration in a timely manner.  The problem could occur months or even years after the treatment was provided. If for whatever reason your endodontically treated tooth does become problematic and it is determined it can still be saved, your treatment options usually include: retreatment, endodontic surgery or extraction.  The decision is based on a thorough exam of your tooth’s status and discussion of your options and prospects for success.  Usually retreatment is the first choice in trying to solve a failing root canal, as it is the most conservative and carries a reasonably good success rate if there are not complicating factors.  

Once a decision is made that retreatment is your best option for trying to solve your problem, the procedure is performed in the following manner: 

First, it is necessary for Dr. Marshall to gain access to the problem area, which is usually the tip of the root.  This involves a process called “disassembly”, which refers to the removal of all the materials impeding access to the apical region of your root(s).  An access opening needs to be made through your crown or filling, if there is a post(s) it must be retrieved, the root canal filling material is then removed and finally any blockages, calcifications or other obstructions need to be dealt with.  Disassembly can be very time consuming and sometimes this phase alone requires one or more appointments.  If any phase of disassembly is not possible, the success of the treatment could be jeopardized. 

Next, the inside of your tooth is examined for cracks, additional canals or other unusual anatomy which requires treatment.  Then, in much the same manner as conventional root canal treatment, the canals are cleaned, sterilized, dried and sealed, and a temporary restoration is placed.  

At this point, you will need to return to your dentist as soon as possible in order to have a new crown or restoration placed on the tooth to protect it and restore full functionality.

Retreating a failed root canal is a more complicated and time-consuming procedure than the first time your tooth was treated, since not only is disassembly necessary, but also the natural tooth anatomy has usually been disrupted, which requires more time to solve.  Consequently, you should expect retreatment endodontics will not only require more time, but will cost more than the initial treatment.