Conventional non-surgical endodontic treatment has a very high success rate when properly performed. However, there are still going to be cases and situations that require retreatment. In some cases this means that posts, crowns or prosthetics may have to be removed or destroyed prior to attempted retreatment. This month's fax concerns factors that we need to examine when we consider cases for endodontic retreatment.
1. What is the condition of the current restoration?
Successful endodontic treatment demands that we constantly think about the Endodontic-Restorative Continuum. This means that attempting to clean, shape and fill the root canal system also requires that we keep coronal contaminants out of the canal space both during and after treatment. Before considering a case for retreatment, we need to closely scrutinize the existing restoration and decide whether it is adequate to do the job. If it is not, then the decision to disassemble has already been made. Restorations with faulty margins are a recipe for failure of the endodontic retreatment and it is unfair to ask to have a tooth retreated when the patient is unwilling to adequately and properly restore the tooth. The tooth will require a new restoration and the patient MUST be informed of this prior to referral or commencement of the retreatment. This is should be made an integral part of the patient's informed consent both at the Generalist and Referral offices.
2. What is the position of the radiolucency?
When considering retreatment options, it is important to examine the position of any associated radiolucencies relative to the root anatomy. For example, if the radiolucency is in the midroot (rather than at the apex) or is close to the most apical position of a post, the problem may be associated with either a lateral canal or a post perforation. Re-cleaning and shaping of the entire canal space is indicated and can often result in sealing of the lateral canal during the repack. In other teeth, intra canal examination with a Surgical Operating Microscope can often reveal a post perforation or iatrogenic defect. MTA (Mineral Trioxide Aggregate) can be used to try to seal these perforations or defects in a conventional mode rather than having to resort to surgery. It is the opinion of most endodontists than whenever possible, conventional endodontic treatment (rather than surgery) should be performed because of its relatively high success rate. Should surgery eventually be necessary, Endodontists prefer that they do surgery up against THEIR OWN TREATMENT, rather than have to rely on other clinicians for treatment of the remaining part of the root canal system.
3. Responsibility Factors
Many General Practitioners don't consider this when referring their cases for retreatment. They must understand that once a second clinician or Endodontist agrees to retreat their patient's case, the responsibility for the case now is entirely in that clinician's hands. The retreating clinician therefore needs to eliminate any factors that may negatively impact upon the prognosis or his ability to optimally retreat the case. He may want to perform certain procedures that allow easier access to canals, posts, broken files etc. In some situations this may involve destruction or removal of crowns, bridges, posts, cores or any other restorations that may have only recently been placed. It is important to remember that while this may incur some short-term cost to the referring dentist, it is infinitely better than having to deal with the consequences of eventual loss of the tooth or of a chronically complaining patient. Occasionally there may be a radiolucency or problem associated with only one root (For example: a radiolucency associated with a missed MB2 in a maxillary molar) the retreating clinician should conventionally retreat the entire case whenever possible. This has more to do with assuming responsibility for the treatment and ensuring that that all aspects of the case have been examined and retreated to the best of the clinician's ability. Requesting (for financial or insurance reasons) that "only the MB root be retreated" is placing unfair constraints on the retreating clinician and places him in an untenable position should the case continue to be symptomatic or should problems develop with one of the other canals/roots. Once the case is referred, these decisions should be left to the person retreating the case.
4. Post Removal/Remaining Dentin
Post removal used to be a formidable obstacle to retreatment. For many years, we frequently had to drill out posts with small burs (often sacrificing large amounts of root dentin or risking perforation in the process). Products such as The Gonon Post Puller and the Ruddle Post Removal System are very effective when combined with specially designed ultrasonically activated tips. It is now possible to remove posts in just a few minutes. Should you frequently have to remove posts, you should invest in one of these devices or consider referring these teeth. They are expensive but are worth it when you consider how important it can often be to retain root dentin in that strategically placed abutment.
5. Surgical Considerations
There are certain cases that are best treated surgically, without disassembly. These teeth most often have newly placed, multi-unit prosthetics with good margins and present with complications such as: short filled or ledged canals, broken files in curved roots, post placement that would be difficult to disassemble without compromising the prosthesis, aesthetic concerns, etc. If the rest of the canal system appears to be reasonably well treated or has an inaccessible problem, the retreating clinician may choose surgical resection and retrofill, though this might not be the optimal treatment modality. Anatomic considerations also must be taken into account. E.g./ Palatal root surgery in maxillary molars and mandibular 2nd molar surgery can be very challenging and difficult. The cost/benefit ratio, the relative importance of the tooth in the overall treatment plan and alternatives (such as an implant) should always be considered and discussed with the patient. Each case must be judged on its own terms. There is no hard and fast rule when considering retreatment and/or surgery. Consult with your endodontist if you are not sure.
6. Financial/Insurance Factors
Although we would like to be able to perform the optimal treatment for each patient regardless of cost, financial considerations and insurance frequency limitations are a reality of life. When considering retreatment options, it is best that the patient pays the endodontist/retreating clinician directly in a manner that does not involve payment from the original treating dentist or insurance carrier. In that way, whatever reimbursement, fee or financial arrangement is worked out between the original treating dentist and patient/insurer will not involve the retreating clinician. It is unfair and unreasonable to expect to refer a difficult retreatment case that has previously has been done in your office and then expect the fee to be discounted in some manner for reasons of insurance limitations or "professional courtesy". Should you need to return your patient's fee some reason, please make arrangements to do this prior to retreatment. It avoids placing the Endodontist in the middle of this negotiation.
7. Furcal Involvements/Perio Condition
The periodontal condition of each potential retreatment case must be thoroughly evaluated. Periodontists like to refer non-vital or retreatment cases to the Endodontist because they understand that lesions of purely endodontic origin can frequently heal by "growing bone" that is not possible with Periodontal treatment alone. Furca accessory or lateral canals (especially in mandibular molars) can sometimes solve furca problems that may have had a questionable periodontal prognosis. Similarly, confirmation of mesial-distal cracks or fractures and confirmation of a hopeless Perio prognosis demands that disassembly be performed to allow good visualization of the pulpal floor and root dentin.
8. Case Selection
The decision to attempt retreatment of an endodontic case must be made with the understanding that this tooth is already compromised and that the prognosis for retreatment cases is ALWAYS lower than that of the original endodontic treatment. When explaining this to my patients, I use the "Soup" analogy. -> I am the "Chef" and someone else has prepared the "soup" with too much salt. I can flavor it, dilute it, change the texture of the soup, or its appearance…but the fact remains that it will probably still be slightly "salty" to the taste. That is something I cannot change. Similarly, canals that are ledged, blocked, torn, perforated or in some way irreversibly altered so that the optimal result cannot be obtained will result in less than the "normal" prognosis. Every attempt will be made to get the best result but there is always the possibility that surgery or extraction may eventually be required. Contingency plans should be discussed prior to initiation of retreatment and it is preferable that the patient signs a consent form specifically outlining the particulars of the case and alternatives. I prefer to draw a MS Paint sketch of the tooth for the patient that describes treatment in detail, alternatives and the associated fees. One copy is kept in the chart and a second copy is given to the patient. That way, there is no miscommunication.
9. Should generalists be performing retreatment?
This question is very controversial. Perhaps the best way to answer it is with another question: What would you prefer to have done if it was your tooth? With a "simple" short filled case (single canal, easy access, no periapical lesion, no blockages etc.) it may not be a difficult choice. If the case is also readily amenable to eventual surgical retreatment (as a "fall back position") then the answer is probably less complicated. However, with disassembly retreatment of complex prosthetics or when aesthetic, periodontal or prognosis issues are involved, there are a myriad of problems that can easily compromise the treatment results. The best way to deal with these cases is to ask the assistance of an endodontist BEFORE you take on the case. When in doubt, consider referring the case. Retreatment cases are often difficult enough to do by themselves. Attempting a further conventional or surgical retreatment on a compromised tooth most often proves to be an exercise in diminishing returns.