The Forefront of Endodontics

James A. Smith Jr, DMD (JS): I think we'll all agree that all of the components are important, but the most important ones are debridement and disinfection. What we take out of the tooth is a lot more important than what we put into it. As an endodontist, you can perform a good obturation, but if it wasn't cleaned and disinfected well, then you have a root canal that can fail.

James Bahcall, DMD, MS (JB): One of the other ones that I feel is just as important, maybe at the periphery of the triad, is the restorative treatment. We all understand from the literature that has been published that great endodontic treatment can fail if the subsequent restorative treatment doesn't meet the standard of care. We're guarding the endodontics, ironically, with restorative treatment that's been demonstrated to provide a good prognosis. That's not to say that you should compromise your endodontic treatment, but the bottom line is that the restorative aspect of endodontics is just as important as the obturation regarding the long-term prognosis of the case.

Brooke Blicher, DMD (BB): We're all coming from the same place. You can do the best endodontics in the world, but if it's leaking, it's going to fail. You can also do the worst endodontics in the world, but if it's sealed well, sometimes it turns out okay. In my own practice, the part that I spend the most time and energy on is the disinfection and making sure that I am using the appropriate irrigants in adequate concentrations for the appropriate amounts of time. I ensure that I'm getting into all areas of the anatomy. I guess that bridges the gap between cleaning and shaping, but by getting the irrigant solutions into contact with all of the spaces inside a tooth and getting your intracanal medicaments in there, you're making sure that you're eliminating bacteria, both to treat infections and to prevent them from occurring.

(ID): Besides a third molar, because I don't see a lot of endodontists treating third molars, what would you say would be the most difficult tooth to treat?

(BB): Any tooth in a challenging patient is going to be the hardest tooth that you treat. If it is in a wiggly 8-year-old, a maxillary incisor can be the most difficult tooth that you treat all month. I'd rather treat a calcified, distally inclined maxillary second molar in a 65-year-old patient who can sleep while I'm working any day. Premolars may seem challenging sometimes because their anatomy can be a little complex; you have a little less room for error as far as access openings go. In addition, some mandibular incisors have more anatomy than clinicians are used to. When appropriate, cone-beam computed tomography (CBCT) can take the mystery out of it. If, based on a preoperative image, I'm questioning whether or not there's some additional anatomy in one of these teeth, I'm grabbing a CBCT image, and what used to be challenging isn't anymore.

(JB): It's funny because, as an endodontist, I get asked that question a lot. I always say that if you really think about it, every tooth is unique like a thumbprint, so really, the greatest challenge is always the tooth that you're currently working on.

(JS): I want to echo what you said about CBCT. That has really completely changed the way I practice. I take a CBCT scan for every tooth that I treat. Lower bicuspids that have fast breaks in the apical third are some of the most difficult teeth for me to treat. Lower bicuspids with multiple canals and lower central incisors can also be some of the most difficult teeth to treat because you don't have much room for error, particularly if you're looking for a calcified canal under a crown. People think that centrals are the simplest, but they can actually be really difficult to treat, as well. CBCT does give you a heads-up though. An endodontist friend of mine used to say that he doesn't descend into the great abyss without first acquiring a CBCT scan, and I subscribe to that theory.

(ID): As a restorative dentist, I find that some dentists are in a hurry to extract a tooth that I feel can be saved. What criteria do you use to make the decision between re-treatment, apical surgery, or an extraction?

(JS): The first thing that I look at is the structural integrity of the tooth. Is this tooth really strong enough to withstand re-treatment and then be re-restored? The second thing that I look at is the CBCT scan because I want to find out why the initial root canal failed. Many times, you'll see a narrow band of bone loss along the lateral branch of the root, and virtually, that's a road map to a fractured root or a cracked root. If it is a cracked root, it's done. If it's a poorly structured tooth without much tooth structure left, you have to ask yourself, "After I re-treat, what are we going to have left?" If I see a missed canal, and that's the reason it failed, and the other factors are fine with a structurally sound root and no evidence of a root fracture, then I'll elect to re-treat.

(JB): This is something that we see almost on a daily basis. As an adjunct to what Smith said, the first thing that we do is identify the etiology. From there, we look at the integrity of the restorative treatment and the previous canal obturation. We do that with periradicular radiographs and CBCT images along with looking at not just the canal morphology but also the periradicular morphology to see if there are anatomical reasons why root-end surgery wouldn't be effective or practical, such as due to the position of the inferior alveolar nerve or the maxillary sinus. Therefore, it's really a combination of a number of different data inputs that informs our decision. Obviously, as endodontists, we're going to want to try to save every tooth, but in reality, we're not trying to save a tooth if it only buys the patient an extra day-we look for a better long-term prognosis. We can all agree that 5 to 10 years ago, the pendulum swung more toward the idea of removing a tooth and placing an implant if anything was remotely out of the question. However, with the availability of CBCT and greater knowledge regarding the survival and failure rates of implants, we've seen a swing back toward the idea of trying to save more patients' teeth. It's a fine balance, and it's a matter of really understanding the data points that you bring in as a diagnostician before you treat. From those points, you're able to get a pretty good idea of the direction to go in terms of root resection, re-treatment, or extraction.

(BB): We have a lot of medical professionals who work at Dartmouth College near my practice, and we talk about engaging in shared decision-making with patients. I lay everything out, including the literature, the evidence, and the criteria that Smith and Bahcall have already covered. Also, what are the patient's values? A patient may say, "I don't want to put any more money into this tooth," or, "I don't really care if I have a replacement." Alternatively, a patient may say, "I always want to have an implant as an option in my back pocket, so I want to try to save this tooth at any cost." Cost and time are both factors. Ultimately, with few exceptions, it's a decision that should be made by the patient. Obviously, we don't want to perform treatment that we're not comfortable with, but we can guide the patient in his or her decision-making. I'll sometimes try to predict my patients' decisions before I walk into the room, but I like to sit back and just kind of lay everything out and say, "OK. Ultimately, the decision is yours. I can answer any questions and provide guidance, but what are you thinking?"

(ID): I agree with what you've said about letting the patient make the decision because I pursue a similar strategy. I come into the operatory and say, "Listen, I'm just a referee. I call it as I see it, but it's your mouth, your time, and your money." Ultimately, it's their decision, and I want to be co-diagnosing.

James Bahcall, DMD, MS, is a clinical professor in the Department of Endodontics at the University of Illinois at Chicago College of Dentistry, Chicago, Illinois.

Brooke Blicher, DMD, is an assistant clinical professor in the Department of Endodontics at the Tufts University School of Dental Medicine, Boston, Massachusetts, and maintains a private practice in White River Junction, Vermont.

James A. Smith Jr, DMD, is an adjunct associate professor in the Departmentof Endodontics at the University of Alabama at Birmingham School of Dentistry, Birmingham, Alabama, and maintains a private practice in Birmingham, Alabama.