Biomimetic Dentistry for Endodontically Treated Teeth

Dr. David Alleman first created his Six Lessons Approach for vital teeth, but the same conservative principles can benefit endodontically treated teeth too. Compared to traditional techniques for retention and bonding, the advanced adhesive and stress-reducing techniques of biomimetic dentistry are better suited for treating non-vital teeth, which are more brittle and susceptible to cracking than fully hydrated teeth with healthy pulps. This episode outlines how biomimetic techniques approach endodontically treated teeth differently and the research that supports these protocols.

Articles referenced in this episode:

• Kishen A., Vedantam S. Hydromechanics in dentine: Role of dentinal tubules and hydrostatic pressure on mechanical stress-strain distribution. Dent Materials. 2003;23: 1296-1306
• Magne  P,  Belser  U. Rationalization of Shape and Related Stress Distribution in Posterior Teeth A finite Element Study Using Nonlinear contact Analysis. J Periodontics Restorative Dent. 2002;22-425-433
• Jayasooriya  PR,  Pereira  PNR,  Nikaido  T,  Tagami  J. Efficacy of a Resin Coating on Bond Strengths of Resin Cement to Dentin. J Esthet Restor Dent 2003 15(2)105-113
• Fennis  WMM,  Kuijs  RH,  Kreulen  CM,  Verdonschot  N,  Creugers  NHJ. Fatigue Resistance of Teeth Restored with Cuspal-Coverage Composite Restorations. Int J Prosthodont 2004 17(3)-313-317

2025 training programs:
Biomimetic Mastership - class starts May 12. Learn more and register at allemancenter.com/mastership

In-Person SLA Workshop Dates:

• August 8-9
• October 24-25
• December 12-13

Learn more and register at allemancenter.com/training

Instagram
@david.alleman.dds
@davey_alleman_dmd
@allemancenter.com

YouTube
@allemancenter

Transcript

0:33

Hello. This is season two, episode 11 of the Six Lessons podcast. Today's topic is endodontically Treated teeth endodontically treated teeth were not originally part of the six lessons approach to advanced Adhesive dentistry. But obviously every dentist that is fixing vital teeth eventually has to fix some non vital teeth. The traditional approach has always been full coverage and many full coverage crowns that have had endodontically treated roots have failed. And I saw that very graphically in the first 17 years of my practice, led me to quit dentistry for six months, and then I became enthusiastic about the opportunities. or the chances of a prevention of root canals and a prevention of crowns through advanced adhesive dental techniques. And so the first concepts that we approached for Vital Teeth turned out to be the best concepts. Also on non vital teeth. But non vital teeth have one huge disadvantage. The structure of a tooth is functioning best when it's hydrated. The hydration of the tooth comes from the pulp. If the pulp is missing, the hydration of the tooth is decreased by about 60%. There is some hydration that is coming actually from the PDL and helps the tooth have some flexibility. But the important article that was definitive in establishing the difference between vital and non vital teeth, in a restorative context, was published in 2007 by Kishen and Vedantam. In 2007, we had already been teaching the six lessons approach to practicing dentist for four years. But when Kishen and Vedantam came out and it was obvious as we talked to more dentists and top more dentists, that preventing endo is great and preventing crowns is great. But if a tooth already has a crown or already has endodontic treatment, what do we do in those situations? Do we still rely on mechanical post build ups, retention forms, ferrule development? All of these classic prosthodontic techniques that have been tried and implemented for almost 100 years, still had failures. And so the question is, could you reduce the number of failures that were catastrophic, or could you increase some of the failures that might allow a repair? And as we applied the principles of the six lessons to ended on include treated teeth, it became obvious that the answers to those questions were, yes, we can decrease the number and the severity of the failures. In the six lessons approach, we always start by an analysis of our failures. That's how I decided to not quit dentistry. I felt like the failures could be changed, and the three types of failures that have been identified in the literature are clinical failures, where there's a chip of the outside or the restorative material, the outside of the tooth enamel, mostly, or a, crown or anomaly or a composite restoration. If there is a chip to the tooth and the patient can feel it with their tongue, we call that a clinical failure because a patient's aware that something's there. They feel it with their tongue. They come to the dentist, say something is broken. Quite often those clinical failures are added to a biologic failure, which is preceded the actual fracture. And so a biologic failure would be there is a gap or a crack underneath the restoration or into dent and that is infected. And this leads to crack propagation. And reinfection or re decay. And so this biologic failure if we can find that early then we're able to treat that before a lot of damage through fracture decay is happening. And so we have a risk assessment that we've taught in lesson two from day one and the six lessons approach. And it was one that I developed to help me make an analysis on teeth that were asymptomatic. In other words, if a patient comes in and a part of your tooth or part of the restoration is broken off in their hand, obviously it is fractured. But what was that like before the tooth or the restoration broke off? Well, there was some type of crack or gap allowing re-infection or a crack propagation. And so once I understood that, we made a risk assessment and the risk assessment was based on the remaining tooth structure that was present, now the remaining tooth structure in a vital tooth always includes a pulp, but in a non vital tooth. This risk assessment is actually even more important because we know from many traditional studies that teeth that have had root canal treatment but do not have full coverage, protection of the cusps are more likely to fracture early. Now that goes halfway up the hill of trying to figure out how to prevent these catastrophic fractures, which would go into the root, from happening. And so this kind of an anthem says your three times is more likely to have a brittle root and a fracture in a root in a non vital tooth as a vital tooth. But if we do have the ability to stop a fracture currently before it gets to the root, we can have a great success in restoring these teeth without crowns, which again removes vital part of the two structure that we've identified and named as the bio rim. And the naming of the bio rim. Identification of that came in initially from a finite elemental analysis study that was done by Urs Belser and Pascal Magne, 2002. once that was identified with this final elemental analysis, it showed that under occlusal function, unless you have an idealized vertical function, you have a tremendous stress concentration in the cervical 2 to 3mm of the tooth. That's the part of the tooth. It's under the hydrocarbon tour. And so in the six lessons approach, we've always taught that the critical to structure is below the contour, the non-critical two structure that could fracture without causing a biologic or a catastrophic failure is the top part of the tooth or the three millimeters on top. If you have a short molar, it's about six millimeters. you have a taller molar, it's about seven, sometimes an eight millimeter, coronal portion of the tooth from the siege to the marginal ridge was someplace between 8mm and 6mm. We have three millimeters. That is critical below the height of contour and then three millimeters non critical on the top above the higher contour. And those teeth are quite often the cluster on lead or in extreme situations of crack propagation we have preparation that would be an overlay preparation. But again the on line of two structure in the six lessons approach The primary reason for that is visualization of decay. This being identified with caries detecting dye and the removal of cracks which is being identified with dehydration or application of self etching primers which help the cracks be visualized. So once we have the idea we're online for visualization, this also, is what we do in a non vital tooth. So in a non vital tooth if we have pulp that's dead, obviously we have a different approach in part of the dissection of deep decay and deep cracks. We approach the dissection of cracks and the removal of carries differently in a vital tooth versus of non-viable tooth. In lesson one, we've talked about how we create a peripheral seal zone that's inside the DEJ and we work carefully towards the central stop zone, which is a millimeter around the pulp. And we stop there because we don't want to expose the pulp. Exposing the pulp triples the chance that the inflammatory response will be, fatal to the pulp. And so the non vital tooth, the excavation of decay and cracks can come instead of the outside in. It can come from the inside out because we're not worried about the pulp dying. It's already been extrapolated. It's gone. But we can look at a crack inside a pulp chamber, and we can dissect that crack inside a pulp chamber. The same with decay. Deep decay would be completely removed instead of partially removed. As the six lessons approach on Vital Teeth would recommend. And so once we have. This carries removal employed in a non-viable tooth and a crack removal endpoint in a non vital tooth. Quite often it will be going down into the root deeply, and that deep dissection of cracks and decay on a root from the inside out would stop by measurement at the PDL or a little bit before the PDL to help, establish a blood free, isolation. And these are all advanced techniques. These are all techniques that Davey has been the greatest pioneer of. The copper band inside the stainless steel matrix for isolating these teeth that are basically cracked to the level of the alveolar bone. And these nine 10, 11 mm dissections of decay and cracks. And then the isolation of those dissection becomes helped if part of the root can be preserved, even though it has a small crack. It separates the restorative process from the PDL, and it allows the band, which in this situation of the double band technique is a stainless steel band that stabilize in the copper matrix band that is pushed down with force to do a blunt dissection. But if you have a little lip at the bottom, or even a lip of two millimeters on a ten millimeter dissection, it gives you a sure lip to hold your matrix in. and it's an advantage in these very deep, situations and of course, situations where you're restoring teeth. They have such a variety. But basically the longer a crack is, left in a tooth, the longer it gets. And these dissection of these deep cracks under the root. In every other system of restorative dentistry, these teeth are condemned as unrestorable Unfortunately for the people that teach that they haven't been trained in the six lessons and they haven't restored some of these unrestorable teeth. Now, if you have an unrestored tooth by somebody else's criteria and you save that tooth for two years, four years, six years, eight years, nine, ten years, 20 years. The definition of unreasonable has to be based on how long the patient lives, because many of these restorations that we've performed have been permanent on patients that were restored when they're 60 or 70 and they died when they were 80 or 90. once the tooth is taken out, then the patient is usually left with the idea of having no, restoration, which is an option if you have 28 teeth and you lose one, that means you have 27 teeth Can a person live to be 100 with 27 teeth? Absolutely. But can they live with 26 or 25 or 24 or 22 or 23 or 20? In Japan, there is a program in the National Health System for dentistry is that they know that the quality of life is limited. If the patient has less than 20 teeth. And so in Japan, the standard for the national health insurance for the dentistry The program is 2080. Or maybe it's 8020. But the idea is that by the time the patient's 80, if they have 20 teeth, then we will consider this successful dental treatment not impacting the quality of life. Esthetics in Japan isn't a big deal. You know, sort of missing a few front teeth and might not be a big deal. They have a fractured front tooth. I mean, all of these give, a broad ability to create your diagnosis based on what you want that patient to have. And that should have, input from the patient as the patient. Are you okay? Losing eight posterior teeth? You know, if you are well, then you can lose four on one side and four on another side, and you still have your bicuspid and all these. You look good. You can still chew with bicuspids. I mean, these are all real practical considerations that worldwide, different countries and different cultures have approached in different ways. But in the United States, we're usually we have options of doing a root canal versus doing an implant or doing nothing because the patient has sufficient teeth for their goals of how they look and how they function. Then we just have these discussions with the patient and we say, you've lost some teeth. These teeth can be saved that you have. Are you interested in doing that? It's your choice. You know, it's your body and most spaces. I'm pretty much 100% of the patients that come into my office for the last 25 years, maybe longer, have always said, I'm coming here because I want to save my teeth. And maybe they have a grandmother that didn't like her dentures, or her parents had said problems with tooth loss. But, if a dentist has confidence that what they're doing is going to preserve that tooth as long as possible, the vital tooth is the one you can pretty much guarantee if you have 50% of your biofilm and you restore it with a stress reduced direct or a stress reduced indirect technique with the bio based being indirectly bonded in that 30 to 50 megapascal or range, then you can just tell the patient, you know, we've done a million of these teeth in our network, including all the doctors that I've trained, and these million teeth have such a success rate. We basically say, we can guarantee this tooth to be in your head for life. That statement is not applicable in teeth that we've already had. And so or teeth that have have cracks that aren't fully dissected. We've had many cases that we treated over the last 25 years of teeth with cracks into their roots, using the principles of six lessons for adhesion and lesson two for dissection. Then we have the ability to say, this tooth that has a crack into your root may not be a permanent restoration, and that's the best thing to say. How long is it going to last? We didn't really have good numbers. I think we have enough numbers in our network now to say that if you have a crack in a root that cannot be completely dissected because it is, let's say mid root, that we have dissected enough of these teeth and restored them with the wallpapering technique. That will be our our topic in our in our next, episode. but we have enough experience with these teeth to say in these hopeless cases we still can guarantee five years. But in reality, the teeth I have, I would say I can pretty much guarantee you'll have ten years, but we have lost several teeth at that ten year mark where eventually the mid root crack has gone epically. And now we have a periodontal condition that's taking out some, buccal bone, for example, in a fistula or an abscess and be better to remove that, to limit that, bone loss. And if a patient wants to do an implant, that's important. That helps the most of the patients I've treated that are in their 70s. And then they get to their 80s, if they lose one tooth, one more tooth, it's not the end of the world, but it's been explained to them when we first treated that this tooth is at risk of being lost, and it's at risk of being lost to a much greater chance if the tooth had not had a root canal. And the patients, you know, they they've come to our office because the only option they were given was extraction, an implant. And so they've come to our office from different states looking for an option. And, you know, we say we understand that most dentists think these are hopeless, and they may be hopeless for the rest of your mortal existence, but you don't know how long you're going to live. But if you lose this tooth and you're 80 years old, it might be different then if you lost another tooth, for example, a front tooth. But fortunately the front teeth have less forces of occlusion. They have about a 10th of the forces of occlusion that back teeth. So all of the teeth that I have lost with this, what we call lesson seven approach, where we apply the six lessons approach to inadequate treated teeth, all of the teeth that we have lost, which in my in my case have been for teeth. And over 20 years those have all been posterior teeth where the forces of occlusion can be up to 200 pounds per square inch, where anteriorly we have maybe 20 pounds per square inch because you don't chew normally on the front teeth. Now, if a person has lost back teeth and that changes and forces get higher on the front teeth. But in the six lessons approach with the wallpapering technique, which will be our next, topic, we've had one, restoration that did fail, but it failed clinically, meaning the restoration of the root that had cracks and deep decay anteriorly. When it was rebuilt, it was rebuilt with two failsafe systems. And the six lessons has been using these these since 2003. The first failsafe system was a resin coating of microfilm flowable that was demonstrated in 2003 by Jayasooriya and Tagami and his, Research. There's in vitro study, but then we also the next year, 2004, we had studies that showed a failsafe can be built underneath the knee. Now replacement by placing ribbond and this was done by Willem Fennis and his team, other researchers at Nijmegen University, in Holland. But these two systems of a micro field or a nano filled hybrid layer being protected by this resin coating, and then the fiber ribbon being placed, as a added failsafe, secures the bond to the remaining dentin that you're bonding to. And if you did have a failure over under function, you would have a failure on the top half or non-critical portion of the tooth. And this has happened once in our office. It was while a patient he had lost all of his posterior teeth, was having implants, and he heads, anterior teeth are now starting to fail. And he wanted to save his anterior teeth from extraction and implants. Anyway, we we restored one tooth. That was six years later. He had a a failure of the enamel replacement, and we were able to repair that. And now, a couple of years later, he's into eight years with this, lesson seven restoration using the six lessons. Approaches. And he's very happy that he's saving his front teeth. And I think he's happy with the implants he's had in the back teeth. And he's 77 years old now, and, you know, it's like when he's only 70 years old, he was thinking differently than when he's 77. And I'm 73, and I'm thinking much differently than when I was 63. But personally, I have lost one tooth from a vertical fracture, was not, diagnosed. I think I mentioned that in an earlier, podcast and I've chosen not to have that replaced with an implant. I do fine, I look okay, you know, it's like it doesn't bother me. Another patient would have a different feelings about, replacing a missing, a missing tooth. But all of these questions and the difference between a vital tooth, a non vital tooth, I believe that's foundational. Before you start learning the techniques to reconstruct and ended up if we treated teeth and then giving the patient that option. But most patients they will still say Implant is going to cost me $3,000. A restoration is going to cost you, cost me $1,200. I still have a little bit of money. If I have a failure that can be repaired, I'm still coming out ahead economically. But in reality, the idea is that what you want to do is you want to do the thing that restores a tooth, that doesn't damage your adjacent tooth and a missing tooth. Additionally, way before implants were, were viable when I graduated 1978, implants were still not long term. They were almost all fail at three years in 1978. That's changed a lot, over the next four and a half decades. But implants are relatively expensive compared to what we do with, offering the reconstruction of involuntarily, treated teeth. But again, I want to emphasize that the vast majority of teeth that are non-viable and that are restored without crowns and using the wallpapering technique of the six lessons are doing just fine. And we have hundreds of thousands of teeth that have been restored by dentists who have been trained by master teachers. Of the six lessons approach from around the world. we see very high patient satisfaction, particularly in countries where implants are a little prohibitive as far as the expense, to the patient. and adhesive restoration can be done for a fraction of the cost. And now we're seeing, in my opinion, at least a, an equal survival rate, as implants, because implants don't have 100% success, a survival. Right? In some studies, we've had 20% failures of implants. And of course, it is operator dependent. operator variability is a big part of the six lessons. We have a standardized protocol, a very specific set of protocols that need to be done to ensure that we maximize the bond strength by minimizing the stress to the hybrid layer. And so that's called the adhesive equation. That's been a fundamental principle that I learned from my second mentor, Gary Unter Brink, in 1998. But all of these variabilities, if the person who's doing it doesn't do it right is like anything else, but it is something that needs discipline and it needs practice. And the more you practice, the more subconscious and automatic it becomes. And that's the definition of mastering, biomimetic restorative dentistry. So with that, we're going to sign off and, next, podcast will be our 12th of the season, I believe our last of our season two. I've enjoyed doing this, and we've had a lot of good feedback and we had a lot of people coming into the mastership after they, have their interest piqued or they have some more in-depth questions they’d like answered. And we invite all of you to take advantage of the hands on and the online zoom instructions that we give. with that, we will sign off, get bonded, stay bonded till next time.