Wallpapering Technique for Endodontically Treated Teeth

The wallpapering technique is a key protocol for extending the function of endodontically treated teeth. More brittle due to their reduced hydration, non-vital teeth are more prone to fracture, so using fiber in this way creates a fail-safe that prevents failure beneath the coronal portion of the tooth and reinfection of the root.

Dr. David Alleman discusses how he helped pioneer this technique and other advancements in adhesive dentistry for cases with non-vital teeth in his Six Lessons Approach to Biomimetic Restorative Dentistry.

Articles referenced in this episode:

• Deliperi S, Alleman D, Rudo D. Stress reduced direct composites for the restoration of structurally compromised teeth: fiber design according to the wallpapering technique. Oper Dent. 2017, 42-3 (233-243)
• Belli  S,  Donmez  N, Eskitascioglu  G. The Effect of C-factor and Flowable Resin or Fiber Use at the Interface on Microtensile Bond Strength to Dentin. J Adhes Dent 2006_8-247-253
• Belli S., Et al. The effect of fiber placement or flowable resin lining on microleakage in class II adhesive restorations. J. Adhes. Dent. 2007; 9: 175-181.
• 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
• Erkut S. Highlighted Microleakage in Overflared Canals with different fiber reinforced dowels. Oper Dent 2008 33(1)92-101.

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Transcript

0:33

Well, welcome to season two, episode 12. We're going to talk about restoring endodontically treated teeth. And the article that we're going to be featuring is an article that we published in 2017 and the Journal of Operative Dentistry here. It's called The Wallpapering Technique by Simone Deliperi David Alleman and Dave Rudo. So what is the wallpapering technique? Well, the name actually came from our good friend and partner Wendell Robertson and, Wendell Robertson has a very creative mind. He invented the term bio base many other clever sayings. But wallpapering was when we were learning the Ribbond technique, or I was teaching the Ribbond technique to him, and then he went to Sardinia and had some advanced courses with, Simone Deliperi on using Ribbond in endodontically treated teeth. It just appeared to him that wherever he put it, it was like you're putting wallpaper on a wall. Well, for the younger listeners who don't even know what wallpaper is, in the old days, if you wanted to change a wall's color or more particularly put a pattern on a wall, then papers that were about this wide were created, and then you would put a, sticky material called wallpaper paste on the back of the wallpaper or in advanced situations. And this was bringing back 1975, the first year of dental school. Linda and I, in our first apartment in San Francisco, wallpapered our apartment with some pretty cool looking, printed papers. They were pasted, so you just had to wet it. You didn't have to mix the wallpaper paste, but I digress. But you can look that up wallpapering in the old days. But the idea is, when we started to understand what Ribbond did that started, in, a few papers, it just happened to have a few collections of some of the early papers the very first paper that really had to do with using ribbond in a stress relieving situation, which is the purpose of the wallpapering, but also the idea of Ribbond stopping fracture that's also integrated into wallpaper technique. But this paper by Sema Belli that was published in 2006, and this paper published the next year in 2007 by some of Belli and her team, both showed that placing ribbon on an axial wall or a pulpal floor. The first paper was the pulpal floor. The second paper was the axial wall. So I guess technically, if you're going to wallpaper, you'd have to put it on the wall. But the first one was on the floor, so maybe we should call Wendell could have called it the carpeting technique, but the combination of pulpal floor and that's your wall that surrounds the pulp. These are the areas where the wallpapering technique or the placement of the fiber, protects the pulp from having a weak hybrid layer or a weak, weak seal. And so when we started to implement that, in the year 2006, for that purpose, we had already started to implement placing of fiber, underneath a restoration to prevent a fracture into the dentin replacement. And that was based on a paper by Willem Fennis published in 2004. that was a year after we started teaching six lessons. So in the six lessons, the idea of a fail safe or a secure, situation where if you had a fracture of your name replacement by placing Ribbond underneath finish showed that it would not fracture into the area close to the pulp. But then the two years later, 2006, when it showed that it actually made what was called a secure bond. The secure bond idea had been validated in 2003, and the secure bond was theorized first by Evo Krejci in 2000. In a paper published in AD, and Krejci was trying to get his mind wrapped around different approaches to adhesive dentistry, and two of the approaches. First, he called a total bond approach in a secure bond approach. And then he talked about a separate bond approach. Well, these approaches that are not connecting the tooth like a bonded amalgam would be an example of a separate bond. Then that approach, doesn't really mimic a tooth very well. And so we call that a non biomimetic adhesive approach where you're sealing the dead, but you're not connecting the seal dentin to the restoration. But the other two approaches a total bond or a secure bond strategy, the total bond. The idea is you're trying to have the same bond throughout the tooth. And, you know, they were thinking that that would be ideal. But actually the tooth itself has different levels of connectivity. In the natural state, for example, enamel is connected to itself at around 11 to 30 mega pascals depending on the portion of the enamel that you're trying to pull apart. That's related to the way the enamel develops. When the, a mellow blast do, they're weaving and dancing as they form enamel. Quite extravagant. Very beautiful to think about how these enamels, are formed. But that strength of 30 max is a lot less than the actual cohesive strength of the DEJ For example, at around 50 or other parts of didn't have a cohesive strength that are way above 30 mega pascals. But if we in a biomimetic approach, say, if we can get our restoration connected to the tooth at the same strength, that enamel is connected to itself, that's kind of like the bottom line. If you got something higher for that would be great. But the connection of the tooth to the material is dependent on many factors, and the factors are in the dentin. How much hydroxyapatite you're trying to bond to. And if you're trying to bond a material that has a high bond ability, but you have a substrate that takes time for the bond to mature, then that is called a difference in the hierarchy or the levels of the hierarchy of bond ability. Of course, this is a proprietary concept that I came up with to help me understand why certain restorations fail in certain places, and other restorations fail in different places. And, it turned out that the failures are always low in the tooth or high in the tooth. The high failures are fractures in the enamel, the low failures or fractures in the dentin, the fractures that are lower and close to the pulp, or the ones that are the most biologically threatening and detrimental. And so a biologic failure that allows infection, the pulp kills the pulp. But a clinical failure that would just be the enamel chipping would be very repairable and not biologically detrimental to the health, of the vital pulp. So all of these concepts, as I was trying to figure out how to make an ideal restoration in my mind, came to the conclusion that if Evo Krejci’s four types of bonding strategy, there was one that was really superior and that was a secure bond strategy where certain areas of the restoration would have a little lower cohesive strength. So in the case of failure of the enamel, it would not go deeper, closer to the pulp. And the idea that you stayed bonded around the pulp and never violated that, even if you had, over time, some type of fracture into the enamel and or the dentin replacement. That was a very appealing concept. And it was proven in 2003 and 2004. In two papers, one from TMD University under the auspices of Jayasuriya, was the lead researcher Patricia Pereira was also on that team. Toru Nikaido also Junji Tagami but they showed that there was a way to construct a restoration, that if you had the hybrid layer in place, and then you put a resin coating, and the resin coating that they used was a micro filled flowable then if you cemented with some type of composite restoration that wasn't exactly the same as the micro filled flowable, and that usually has some kind of hybrid, characteristic or even a micro hybrid characteristic. The difference between the micro, filled composite and a micro hybrid composite, or a micro filled composite and a hybrid composite. Turned out that if you took the restoration apart and tried to pull off through some type of tensile or even, shear, stressing that you would always leave the dentin bonding system that immediate dentin sealing covered and that resin coating that was covering it never failed. And so that was called a secure bond strategy. Again, three years previous. By Evo Krecji but Krecji didn't continue to research and think about how that might be achieved. Its first achieve in 2003 by, primarily Jayasuriya, Patricia Perera and the other researchers at TMDU So that's the first idea that you can do something in a restoration that if it fails, it fails in a way that protects the pulp where it secures or it has a safe fail or fail safe characteristic. And so again, after 2003, then we had 2004 from finished showing. That Ribbond had another fail safe characteristic, but this time it was tested not near the pulp but underneath the enamel, kind of mimicking the DEJ DEJ usually stops cracks or diverts cracks, and most cracks of vast majority do not go into dentin And so this mimicking of the damage by the Ribbond was actually the first protocol that I started to use and teach. And this protocol was an addition to the protocols that had used for since 1998 to 2003 is kind of the beta testing for what we called advanced adhesive dentistry that now we call biomimetic restorative dentistry. But now we had two ways to have these failsafe mechanisms. We had one close to the pulp with this resin coating or microfilled. And then we had this Ribbond fiber underneath the enamel. And so the design of a very deep preparation could use both of these, protecting the hybrid layer and protecting a more catastrophic failure from the top. So these two strategies we started to teach together, 2004 and then 2006 came along and explained another concept, combined resin coating and Ribbond placement. And that was Sema Belli's 2006 paper, followed up in 2007. Later experimented with and reproduced university of Toronto by El-Mowafy another experiment by Ossul and his team in Istanbul. all gave the validity to these fiber nets. Are this fiber placement working in a way that it secured the bond, made a fail safe, situation in the restoration and the stress relief that was shown actually totally demonstrated the next year, 2008 by year, cut in and honestly treated teeth. All of these things coming together in these years. And of course, that's about eight years, 2000 and 2008. But we're teaching the six lessons from 2003 to 2008. But the idea that eventually it came together in a strategy for restoring ended, optically treated teeth, both based on a fail safe concept, a secure bond concept, and these working together allowed us to guarantee that the top of the tooth and end of the treated tooth was never going to fail. Unfortunately, research and we knew this going in on the difference between a vital tooth and a non vital tooth showed us that the roots themselves lost 60% of their toughness. They became 60% more brittle after ended up like treatment. And this was the paper that was published in 2007 by Jayasuriya had already been talked about in the literature. But the in vitro hydrated tests that, Kishen and Vedantam did versus the non hydrated and radically treated teeth showed us that, you lose 300%. You should say you decrease three times the ability of the tooth in its roots to not, instigate or propagate cracks. So, paper by Sophia Schwartz, published around that same time, documented many 32 cases of root canal treatment, starting the process of crack initiation, crack propagation, and catastrophic failure. Well, all of these, mean that if you start to restore an ended, optically treated tooth, the dogma of putting a post in a build up and a full coverage crown, which was what every dental school, mostly still for teachers today, was being replaced by no posts and adhesive approach. But the posts that were tested against a riband placement in some part of the root canal or in the coronal portion of an ended, honestly treated molar, that this ribbon was very different from any type of mechanical build up, that was placed. And so Simone Deliperi and I had been using these concepts and directly treated teeth since basically 2002, when the first papers from Sema Belli were being published. Restoring in and on if we treated teeth with this custom made, build up, it could be called the post. But the idea that ribbon was able to in these adhesive lee restored root canal treated teeth, it could absorb the stress of polymerization in this high c factor situation, the ratio of bonded and bonded surfaces in a pulp chamber is very, very high and so if we have, stress of over five in our C factor calculations, then that's going to decrease the bond strength about 80% if left without a stress reducing strategy. And so the stress reducing strategy that I invented was called decoupling with time. What did that mean? That meant that based on the literature leaving a hybrid layer to mature in its chemical reaction for a minimum of five minutes, an ideal 30 minutes would allow that hybrid layer in its polymerization reaction to form the strongest hybrid layer possible. If you started to pull or stretch that hybrid layer to soon in that 5 to 30 minutes, then you'd have a decrease of bond strength anywhere from 80% decrease to 72, 60 to 50 to 30, you get the idea is that the sooner you start to put stress on the hybrid layer, the more reduction of bond strength, because you're stretching and changing the internal, structure of that polymerization of the polymers that are interacting with pulp will fluid and collagen, and, you know, the best paper we, we talked about this in the earlier lectures is the Nikolaenko 2004 paper, which gives a direct evidence, in vitro testing on what it means to, have a hierarchy of bondability what it means to ignore the hierarchy of vulnerability. And one strategy to improve bond strength next to the pulp by waiting a period of time in the nickel ankle paper, the time was about three and a half to four minutes. we understand. And now we've been, you know, doing this in over a million teeth of the doctors that I've trained, that once you do this, the leakage in a deep box or the leakage close to the powerful flaw is eliminated. And that is because the tooth is acting like a tooth. It doesn't have these gaps and cracks, next to the pulp. So the pulps don't die from a reinfection or a crack initiation underneath the restoration. When we use the six lessons approach of deep carries, partial removal and cracks, partial removal, total removal in the peripheral seal zone and partial move removal to prevent pulp exposures on the axial walls and floors in these, deep lesions. So this wallpapering technique, the paper that we published, in 2017, gave a case it's now over 13 years old. the paper when it was, published, we, we waited, six years before that case, had success for six years. So that case now is 14 years old. Simone Deliperi has recalls on that and no breakdown. So here the dogma of putting full coverage on a tooth is disproved. But how does that work? And how is it carried out? Well, when you read the wallpapering paper and operative dentistry, you will see it's a very defined protocol. Unless you understand what the pictures and the photos actually represent, and you're going to have to read the paper very carefully or be trained by Simone Deliperi or myself or anybody else who has been, immersed in the literature that we've been discussing in this, in this podcast, you can see that you have all of the concepts of lesson one dealing with caries Lesson two dealing with cracks. Lesson three with immediate dentin sealing. All of these, obviously the dentin sealing has to be used a a particular protocol with particular bonding system. This bonding system, the Simone use in this case was a two step total etch, dental bonding system called all bond three. So the condition of the smear layer was not with an abrasion, but it was with a total etch. And then the bonding system It's the best one bottle bonding system, PQ one from Ultra Dent would be the other one that would be similar. It had a, thick adhesive layer. That was also the priming. And these one bottle systems, we know that that has a negative effect, particularly if the adhesive is very thin. In this situation, the adhesive has about an 80 micron thickness similar to the thickness of bottle two of the three step total etch approach of OptiBond FL And so Simone has been using this successfully. We know that the bond strength will be 30 or greater. And once the immediate dentin sealing is placed, then the next step would be the resin coating. Less than three. This resin coating in that paper that Simone wrote most of the text, was a follow up on his 2002 paper. So 15 years earlier, Simone had written the paper with Dave Bardwell in the Journal of American Dental Association. And the resin coating at that time, he put it at one millimeter. I've always believed that a half millimeter is more ideal. My second mentor, Gary Unterbrink always said, think of the global composite as a filled adhesive. In other words, if you have a two bottle system like up the NFL or SE bond or Protect bond, the priming bottle is different than the bonding bottle, and the different molecules allow the primer to be effective, and different hydrophobic monomers allow the adhesive layer to get a un inhibited thickness of monomers. So the air inhibition does not stop the polymerization of a thin adhesive layer. And so when you put the light on an adhesive that has a thickness that's substantial, that would be the way to ensure the transformation or the water train will be stopped coming from a vital pulp, of course, on a non vital tooth like this wallpaper and paper is you're not worrying about transmutation, you're just worrying about, air inhibition and creating this fail safe, secure bond strategy. Using the resin coating as the 2003 Jayasoria paper proved. And so as Simone in the 2002 paper, again followed up in 2017 paper with the same bonding system. Now we have a resin coating of a millimeter on top of a, good bonding system. This all bond, three very good bonding system. We have clinical, proof of that. But now, once that's happening, what do we do to make sure that those bonds have that 5 to 30 minute, period where they can mature to the fullest? Well, Erkut paper showed us that if we put Ribbond on these walls of the darkly treated tooth, then the ribbon, if there's any stress of polymerization in that high cofactor preparation, the ribbon will separate a little bit. And that is a stress relief mechanism. There's still a connection with the resin coating and the composite that's next to the resin coating with that Ribbond that connection is only about half of what it would be if it was just composite connected to itself. In other words, the cohesive strength of composite connected to itself is about 40 mega pascals. If you have Ribbond in between this, then you have, little islands and projections of composite that are connected to each other, but you have other areas that are the Ribbond fibers. So if you pulled it apart, it would pull apart at about 20 mega pascals. Now, that's only, Compared to enamel, not as strong as enamel. It's not as strong as dentin But the idea is we're putting this in as this failsafe strategy. You're building that in that in the event that you had a fracture of dentin replacement. And if you treat a tooth, you would still seal the pulp chamber and the canals would not become reinfected. So that was the strategy. We've been doing that, successfully for 20 years, and we've had no failures in the crawl portion of a indirectly treated tooth. I have personally had three failures in the root system of an an endodontically treated tooth. My son Davey, has had a couple in six years, but again, these are in, very thin roots in roughly treated teeth. The failures are not in the coronal portion, but in the root. When that fractures, then you do have a catastrophic failure. But this is out of hundreds of teeth that we've treated. And so the, percentage of failures in involuntary treated teeth are less than 1%. We hope that that stays lower than any percentage of implant failures. You know, time will tell. But the decision of the patient to try to save an endodontically treated tooth, then the strategy should be we want to make sure that that tooth does not get reinfected from the coronal Restorative part of the tooth, the leakage. If it goes into the root, then the root can become reinfected. And of course, if there's any fractures that are not diagnosed and removed, then those fractures will continue to propagate. And then a root fracture and potential catastrophic failures, could be in the future. So when we talk about anatomic, the treated teeth in the six lessons approach, we actually have a different designation. We don't call it part of the six lessons. We call it lesson seven. It's kind of like a caveat saying we're going to use all of the concepts that you've learned in the six lessons, lessons one through six on vital things. We pretty much guarantee, you know, a tooth that's not going to have a pulp die a tooth. It's not going to have a catastrophic failure. There will be some repair of enamel replacements onlays ceramic on leis that are too thin, for example, or composite that wears too much over 20 years. Then we can use some repair techniques on vital teeth. And these usually, mean that there will never have to be a revisiting of the hybrid layer, in these, vital teeth, but in an endodontically treated tooth, we have this problem of the non hydrated roots have become brittle. And so we say to the patient that this tooth will be adhesive. We're bonded, but we can't regenerate the hydrating portion of the tooth which really gives it its toughness so that it doesn't act like a brittle material. Although technically enamel and hydrated didn't are brittle. They're not as brittle as, hydrated dens. And that's the, the, conclusion of the Vedantam and Kishen paper that we referred to earlier in this in this lecture That pretty much finishes up season two We, look forward to doing some more next year. Hopefully, things go well for all of you. And you're able to get the training and the mentoring and making the advances in adhesive dentistry. That can be very satisfying, rewarding to both you and your patients to get bonded, stay bonded, and conserve as much of God's gift to you in the way of teeth as possible. So until next time, we will say get bonded and stay bonded.