Written by L. Stephen Buchanan, DDS Wednesday, 01 October 2008 00:00
In Part 1 of this 2-part article, I covered 3 factors that threaten the credibility of endodontic therapy as the first choice when pulpal pathosis or persistent infection occurs in a root canal system. These were needlessly weakened teeth, abandonment of surgical retreatment alternatives, and inadequate treatment results. In Part 2 of this article, I will cover retreating teeth with poor prognoses, considerations in determining the long-term prognosis of failing root canal cases, and why endodontists who do implant surgery can offer the most unbiased opinions when deciding the fate of teeth with failing endodontic treatment.
Retreatment of Teeth with Poor Prognoses
This one is for the endodontists, and I have been guilty of this in the early part of my career. I started practicing before implants worked—back in the day when extracting a distal abutment meant the patient would have to put up with a partial denture to replace the chewing function or just live without that replacement; we did a lot of weird dentistry we called “heroic.” That’s funny, in a pathetic way, because the term heroic was a self-reference, when it more accurately described the patients undergoing treatment approaches with poor prognoses.
The list of heroic endodontic procedures included the following: repairs of perforations before MTA, hemisections or root amputations of teeth with vertical fractures, forced eruption of teeth having subcrestal caries, cervical resorption or oblique fractures, internal bonding of root fractures, and doing root canal therapy on teeth that periodontists were ineffectually treating. That pendulum swung way too far. Thankfully we don’t have to do that anymore.
However, as much as it hurts to say it, we as endodontists are still retreating teeth with poor prognoses for the same reason that implant surgeons are extracting teeth that could be saved: to a hammer, everything looks like a nail. Despite my best intentions (and fortunately for my self-esteem), I have done this mostly in cases that I now understand to have less-than-excellent long-term restorability prognoses.
Anterior teeth that are broken or decayed below the gumline, as I have been told by prosthodontists, have a very poor long-term prognosis. While we can often restore these teeth with post/core buildups, unless a significant ferrule can be placed a full 360° around the tooth, they are highly prone to vertical fracture under lateral forces. While these situations must be evaluated on a case-by-case basis, in general, patients with this problem will be better served with an implant. Fortunately, due to the more vertical loading, and because we no longer have to stress posterior abutments with bridges, many of these teeth can be salvaged when they have lost tooth structure to cervical levels. Again, these cases must be treatment planned on a case-by-case basis.
Beyond issues of restorability, cases are still being retreated after 2, 3, and even 4 failed retreatments. These are probably the most difficult judgment calls that I make. These decisions require communication with the restorative dentist, the patient, and often another endodontist (in my case, my partner, Dr. Jack Sturm).
To all of my specialist colleagues, please be aware that when endodontists retreat teeth with a poor prognosis, our collective success rate becomes lower. As a result, the confidence other dentists have in endodontic therapy as a predictable way to save teeth also drops. My worst experiences in pursuing implant training have been when an implant surgeon shows me yet another case in which he or she placed an implant after one or more endodontists had treated, retreated, and then retreated the tooth to death. Implant surgeons do not typically see the retreatment cases that work. On the contrary, they see the ones that don’t, and as a result, their viewpoint of the success of retreatment is skewed.
ISSUES IN TREATMENT PLANNING AN ENDODONTIC FAILURE
These are the issues I consider in treatment planning an endodontic failure, in order of importance: the structural integrity of the tooth, the periodontal supporting structures around the tooth, and, finally, the challenges of retreatment.
First, as mentioned above, the best retreatment in the world is not going to provide a long-term prognosis for a weak tooth. One of the challenging decision points, in terms of structural integrity, is what to do about a tooth with a vertical fracture that just barely reaches the soft-tissue attachment. My experiences have taught me that these cases usually fail in the short- or mid-term, and they always fail in the long-term. Early in my practice career, I said (and have heard every new associate in my office say) to a patient with this condition, “We will save your tooth for as long as we can.” This gives me the dumb-chills now to remember my well-intentioned mistakes in this regard—a fantasy that lasted about 18 months into my practice experience. My advice to dentists with limited experience in these matters is to be ruthless in extracting these teeth, unless the patient makes a decision in his or her own worst interest. Of course, this recommendation applies to vertically fractured virgin teeth as well.
Diagnosis of the apical extent of vertically fractured teeth requires the following: at least 10x magnification for internal access cavity wall examination, breaking the contact to see if there is a narrow increase in pocket depth on the outside of the tooth opposing the fracture line seen from within the pulp chamber, and careful viewing of a well-angulated radiograph for crestal breakdown in that area. With regard to the periodontal factors influencing prognosis determination, even periodontists have given up on periodontally compromised teeth. They simply place implants now, as they realize all those years of bone grafting next to natural tooth structure did not yield predictable long-term results. Or even worse, that one should never remove healthy periodontal tissues around good teeth to reduce pocket depths around adjacent loser teeth.
Lastly, I consider the issue of retreatability. In my mind this is a bit like the current concept of criminal justice: 3 strikes and your out. If the tooth has a perforation that needs to be repaired, 3 posts that must be removed, coronal leakage and also apical damage that will require surgery after an extensive disassembly and removal of a broken file, get it out of your patient’s head! These decisions are optimally made with the patient’s best interest in mind, not just in a physiologic sense, but in a financial one, too.
Consider the costs and time required for each treatment alternative, explain it to the patient as best you can, and let the patient inform you of his or her priorities. I have had patients who would walk through 9 miles of broken glass on their knees to save a tooth with a guarded prognosis. It’s their tooth, and unless it just has no chance of being saved, I will accede to their wishes and retreat it if that is what they desire. The key issue for endodontists is to charge for the time it will take to do the procedures, not what the insurance company will pay (typically $100 to $200 more than standard treatment).
Also, the relative difficulties, time, and costs of implant replacement must be considered. In a patient who has taken intravenous bisphosphonates—who has a very low sinus floor or has had a previous implant failure—the equation would favor retreatment of even a challenging case. Conversely, if the patient could walk out in one visit with an immediate implant placed in the extraction socket with an aesthetic provisional crown on it, do the implant. This brings us to the latest trend in the specialty of endodontics: should root canal specialists train to do implant surgery?
WHY IS YOUR ENDODONTIST DOING IMPLANT SURGERY?
My favorite reason for placing implants is because I heard the endo/space maintainer joke once too often (and my converse joke for implant surgeons is, “All mispositioned implants integrate perfectly.”) Seriously, I started training to do implant surgery because I saw the specialty threatened by implant surgeons who had learned to disrespect the possibilities of endodontic therapy, whether their experiences were our fault or theirs. I saw my colleagues (myself included) opting out or being cut out of treatment planning consultations. I knew it was time for endodontists to break out of the in-and-out “mow, blow, and go” concept of multidisciplinary practice. And how has my experience as an endodontist-implant surgeon been? Fascinating and very satisfying.
Do I think that the majority of endodontists will eventually become implant surgeons? No. Those endodontists who practice in less competitive regions of our country will see little reason to add complexity to their day when they are already overwhelmed with endodontic referrals. In those areas, periodontists and oral surgeons still refer cases for retreatment. As a result, it would often be counterproductive to jeopardize those healthy relationships. And obviously, endodontists who do not enjoy doing surgery in their original area of expertise will not enjoy doing other types of surgery. However, for those who are seeing eminently salvageable teeth extracted without an endodontist’s opinion, there is but one alternative: becoming specialists who can offer the best, least-biased treatment planning opinions, because, unlike implant surgeons who cannot do RCT, we endoimplant specialists can do either procedure.
What are some of the things that I have learned about delivering better care to my patients? I understand prosthodontists’ treatment planning process better. I make better decisions about which teeth to retreat and which to extract. And, I have learned that I don’t have to be as sad when I cannot save a patient’s tooth. I have been received with grace and generosity by other implant surgeons, most of whom realize that we are not fighting for implant versus endo, but are fighting to save teeth from being needlessly prepped to be bridge abutments—all this for our patients’ well-being and for a growing public perception that dentists learn from their failures and become more adept at providing treatment that will stand the test of time. And, as an aside, I have learned that you can in fact “teach an old dog new tricks.”
THE FUTURE OF ENDODONTICS
Figure 1. Maxillary anterior area decimated after immediate failure of the 2 implants that were placed by a periodontist. The patient lost 8 mm of vertical bone height as a result of the postoperative infection.
Figure 2. Photograph of maxillary anterior ridge after uncovering the bone graft site. The cost to the patient was the loss of a nondiseased lateral incisor to ensure a better outcome; $10,000 for BMP/titanium mesh/bone grafting and implant placement; a face that looked like a football for 2 weeks after the graft; and 2 years to the completion of treatment.
Despite all of the issues mentioned above, the future of endodontics as a respected treatment for saving teeth is very bright. While the pendulum always swings too far during change, it always returns. Simple regression to the mean is a very serious force in the universe, and it is no different in dentistry. Just as improved technology in endodontic procedures has increased the number of general dentists doing those procedures and has attracted a greater number of dentists to the specialty, so it will go in the implant field.
|Figures 3 and 4. Maxillary molar with long, narrow, highly curved roots treated with GTX Files (DENTSPLY?Tulsa Dental Specialties). Note the exceptional apical control and the 3-D result in spite of limited coronal enlargement. (Figures 3 and 4 courtesy of Dr. David Rosenberg, Vero Beach, Fla, and Dr. Giuseppe Cantatore, Rome, Italy, respectively).|
Implant surgery is no more immune to failure than endo, and as the number of dentists doing implant placement increases, the high rates of success will inevitably drop. And when an implant fails, it is an expensive, 1- to 2-year process to reconstruct the bone that has been lost as a result (Figures 1 and 2). Implant surgery, like endodontics, is not a panacea where the best im-plant surgeons are famous for recreating an appearance that is very similar to a tooth. The fact remains that implants are not teeth, although they are a fairly miraculous artificial alternative. When I think about the turnaround time needed to complete treatment on a pulpally diseased tooth—about 2 to 4 weeks from the start of the RCT to the cementation of the permanent res-toration—implants cannot compare (Figures 3 and 4).
The future of endodontics as practiced by specialists is in question for all of the reasons mentioned above. The days of nearly instant practice success after residency are gone for those of limited skill or knowledge. But for those who continue to learn, who get better every year, who are curious and passionate about their chosen field of expertise—the future has never been brighter. The pendulum always swings too far, but it’s cool to see that it is coming back to center…
Dr. Buchanan is a Diplomate of the American Board of Endodontics and a Fellow of both the International College of Dentists and American College of Dentists. Dentists interested in his videotape series, The Art of Endodontics, and his hands-on laboratory workshops in Santa Barbara, Calif, can call (800) 528-1590. For more information related to this article, visit endobuchanan.com for GTX updates and answers to frequently asked questions indexed by topic. A free online CE course on the GTX System is available, as well as other topics. Questions concerning challenging cases can be directed to (800) 528-1590.
Disclosure: Dr. Buchanan consults for and holds patents to the GT and GTX System of instruments manufactured and sold by DENTSPLY. He also holds patents with the System B Heat Source and is the inventor of the Continuous Wave of Condensation technique.
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