What is Adhesive Dentistry?

Adhesive dentistry has been taught in dental schools for decades and is widely used by dentists today. Bonding to a tooth offers increased adaptability of restorations, allowing for more minimally invasive treatment and preparation, but long-term success with adhesive dentistry is not a guarantee.

Dr. David Alleman repeatedly saw failing composite restorations and realized that in order to improve restorative outcomes, posterior teeth needed more advanced protocols than anterior teeth. Subjected to higher forces of occlusion and with deeper restored defects, understanding polymerization dynamics is essential to a long-lasting adhesive posterior restoration. His research of these principles served as the basis for him developing his Six Lessons Approach to Biomimetic Restorative Dentistry.

Article referenced in this episode

• Gibbs CH,  Mahan  PE,  Mauderli  A,  Lundeen  HC,  Walsh  EK. Limits of human bite strength. J Prosthet Dent 1986;56-226-229
• Larson TD, Douglas WH, Geistfeld RE. Effect of prepared cavities on the strength of teeth. Oper Dent. 1981(6)2-5. 
• Nikaido T. Evaluation of thermal cycling and mechanical loading on bond strength of self-etching primer system to dentin. Dent. Mater. 2002;18 269-275.

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Transcript

0:33

Welcome to season three of the Six Lessons podcast episode two. We'll be talking about adhesive dentistry. The last episode we talked about minimally invasive dentistry evolving with adhesive dentistry and the evolution of biomimetic dentistry from adhesive dentistry. an important distinction, all three of these concepts. Today we'll talk about adhesive dentistry because that's something that every dental school teaches. And every dental school has been doing something with adhesive dentistry for, 40 years. But the differentiation between adhesive dentistry and biomimetic dentistry is very important. But we'll deal with how adhesive dentistry has evolved. And when I went to dental school in 1975 to 1978, the idea of adhesive dentistry, we did etch enamel, for example, on interior restoration. But the only composites we had were chemical cure. So we used a chemical cure, adhesive underneath the, chemical cure composites. And we did etch the enamel. So etching the enamel with phosphoric acid was pioneered in the mid 50s by Michael Buonocore So from the mid 50s to the mid 7070s, when I went to dental school for 20 years, there was really no progress in the idea of bonding to dentin In fact, when I learned my adhesive dental techniques for anterior composites in dental school at the University of Pacific, we were very careful to cover the dentin with dye cal, and that was under the misinformation, the misguided idea that etching the O'Donnell plastic tubule processes with etch would damage them. That is not true. It was a dogma that was developed just with some theories that had no real scientific basis or confirmation. But you do what you learn in dental school. And I would cover the deaden with dye cal. And then I would etch the enamel with phosphoric acid and then, rinse, dry and place our dual cure bonding system. And then we would do the bulk fill with the dual cure composite. And for interior class three restorations, we had some success. But the important thing to understand the difference in adhesive dentistry, success in the interior and adhesive dentistry does asters in the posterior is that the forces of occlusion are ten times in the back of the mouth, as they are in the front of the mouth. I never learned that in in dental school. The research on it actually came in the 80s out of the University of Florida in Gainesville, Florida. Gibbs and other researchers published the bite forces and studied the bite forces of different patients. And we find out that a huge variety in forces of occlusion, a maximum bite force, might vary from 55 pounds to a very slight, low functioning or low stressful occlusal system. 55 pounds is the lowest measured maximum bite force. The highest measured maximum base force in the humans that were studied in Florida was 950 pounds. I mean, that's like 20 times stronger. And so that kind of mass system can break natural teeth that can bend gold. It can do all kinds of things. I've seen these things happen in the patients that I've had in the last 44 years, and then some patients. The bite force is so small that you can restore them with a temporary material like IRM, and it can last for decades. And that's part of the analysis of what we call stress of occlusion in lesson six, but also impacts the idea of how things crack and break and start to fail in lesson two. Well, all of these things, obviously I knew nothing of this as I graduated from dental school and practiced in the Navy for three years. We had success doing bonded composites on the interior, but we did not ever were allowed to use composites in the posterior. When I got into private practice in 1981, I was in Salt Lake City, Utah, and we did our normal amalgam fillings and crowns in the back root canals when the patients had continued sensitivity. And then, full coverage, of course, on everything that had some fractured cusp, for example, even though we didn't even think teeth to know that the cusp fracture could happen progressively and we were creating stress and fractures in our amalgam preparations. This was pioneered in the 80s by Mondiali in, Brazil and with Larsen and Douglas in Minnesota. So in the 80s, after I graduated dental school, people started to think, why are these teeth breaking? Could we do something about them? And the answer was, they are full coverage, full coverage, full coverage. But the full coverage. There's many different types of minimally invasive concepts in a gold omelet or a very conservative gold, veneer crown. You know, there's all types of ways to approach dentistry. But as a young dentist, all I knew is that I would see these cases come down from Idaho. We used to call them Idaho cases. These, progressive amalgam replacing dentists were putting composites in their back teeth, and all of them were failing. They were all sensitive and they were fracturing. And not only did the composite fracture, the teeth were still fracturing like amalgams. So the idea of any type of superiority of, adhesive restoration in the back was totally, frowned upon by a traditional dentist like myself who saw the failures of these early posterior composites. But, you know, I wasn't smart enough at that time to figure out that composites in the front were good, composite the back were bad. I really didn't come across occlusal forces until 1995. The 1996, 1997 when I started to come into contact with my first mentor, Ray bird, lady of second mentor John Kois, took occlusion courses from him in 98, and he actually introduced me to the Larson paper of 81. But the Larson paper of 81 had a lot of information that in my view, did not recommend full coverage as your first, approach, because by 1998, when I was studying with John Kois, I'd been mentor not only by Ray Bird Laurie since 1995, but I had some contact that year at the Ada Convention in San Francisco with Gary Brink and Gary Brink. Introduced me to concepts that made me feel like posterior adhesive restorations were not being done properly. And that's basically, from 98 till now has been my mission to figure out how adhesive dentistry could be successful in the posterior without full coverage. And we discovered that after seven years. But the continued problem with posterior, teeth being restored with composite by only using adhesive. Dentistry, continues to plague the profession because there's not an understanding of how these composites move and shrink. And so what's missing? Adhesive dentistry is the concept of polymerization dynamics, and what that means when these composites are coming together, they're moving. And that movement has consequences for the edges of these restorations. And now every dentist will say they understand the composite shrinks. But then when I asked specific questions on how does that impact your clinical practice? They can't give a cohesive, answer because it hugely impacts, your restoration, because your bond in Denton is destroyed, because it's not decoupled or separated from the bond to enamel. So adhesive dentistry concentrates on the bond to enamel. They depend on the bond to enamel. Biomimetic dentistry is just the opposite. They depend on the bond to dentin and a bond to enamel is nice. We use adhesive principles in the six lessons approach will be bond to enamel. We do the same etching. We do the same adhesive, we do the same. Even a bulk fill on enamel will not be destructive. If the foundational, what we call the bio base is in place. But none of these concepts, obviously, that we invented, that we had to synthesize from the literature were available throughout the 80s and into the early 90s. And so the adhesive dentistry that's taught in school will be very comfortable teaching a veneer prep, for example. And most veneer preps are mostly bonding to enamel, and they will have success. But how about a veneer that has erosion and all of a sudden the enamel is missing, but the dentin is the higher percentage of your bond able to structure. What are the concepts that need to be used to differentiate that type of veneer? Prep from a veneer prepped in enamel? You know, I've done thousands of veneer preps over my career. I have had no demands. I remember Davie and I went to a new group of dentists in Tulsa, Oklahoma, and we found out that they were having veneers. D bond. As soon as we heard that, you know, Dave and I looked at each other like, these guys aren't ready to go to a biomimetic approach. They don't even know what adhesive dentistry is and how to make it work. And part of their problem they were using simplified adhesive systems from three M, and they were bad adhesive systems. And they had D bonds of veneers because veneers do have stress. And if the veneer is not diagnosed as having a different level of the hierarchy of bond ability from enamel to debt, and then that hierarchy brought vulnerability. Even in a veneer, cementation can have negative effects, and the veneers adhesive bond through the hybrid layer can peel off, and a deep bonded veneer is possible, although I've never had that. My mentor Ray Bird Lottie, did in his career, 14,000 veneers never had a deep bond. Why? Because he did understand that if he had dentin as part of the veneer preparation, then he would treat that dentin separately. When he taught that to me, he did not call it immediate dentin sealing. He just taught that, in the first course that I attended in 1995 and in 1995, the bonding systems were just developing. I have a list here of 23 bonding systems that were available in 1995. Of those 23 bonding systems, only. All bond two of the bond AFL and Clearfield lighter bond system, which evolved into the Clearfield systems. But only three out of those bonding systems that were available in 1995 are still available now. Why? evolution says the survival of the fittest means that if you don't have a good product, you're going to die, you're not going to survive. And you know, the free market has the ability to control people, to make choices and change products. And this is what's happened. There are many new body systems that are been developed over the last 30 years that are still, viable options for adhesive dentistry. But when we came to this idea of bonding to. Didn't Raber Laurie Riley say the best bonding systems available right now is called all bond two? Not all bond one, but all bond two. And it was a three step total edge, acetone based bonding system from this company called bicycles still alive and selling all bond three now, which is a bonding system that Simone Della Perry has used successfully for over 20 years. So Biscoe all bond three at that time, all bond two was the best. And so a lot of we'll show you how to bond the exposed dentin. And then when the core array products became more dependable then he would teach. And at that point, the core array product that I had was a, two bottle system, which was called Photo Bond, had a very thin film thickness, which is a disadvantage. It wasn't as good. Ray knew that that was something that needed to change. it's a long story there, but the idea is that treating dentin with a different bonding system, the new treat enamel, that was introduced to me in 1995 by Ray a lot. But the next concept that Robert Lotti introduced to me, actually, two years later, 1997 Yosemite, of course, that I took from Ray, introduced a new bonding system called Liner Bond two and a liner bond two was a It was first in Japan in 1989, started to come to the United States in the mid 90s, and by that time it had the same or even a superior, position than the old bond two. So I learned adhesive dentistry, veneer preps, veneer bonding systems from Ray Byrd, a lady, and a new system which was improved and probably the same as all bond two. And that was liner bond two, not a liner bond one, which actually had a good system. We've talked about that. in the podcast. But all of these ideas of improvements in materials and that changes your approach to techniques or techniques, demand different materials. These are all concepts that were being discussed at Advanced Adhesive Seminars, around the world. But then the next year, in 1998, again at a lecture in Yosemite, or this lecture might have been in Las Vegas at the Ada convention. That would have been 99 anyway, all the dates, they kind of come together and leave in your mind, but in 1997, Ray Bird Lottie introduced the concept that was being talked about, had been talked about for ten years, it had more papers published about it. It was called Sif after, and that was the ratio of bonded ton bonded surfaces. And so for two years, you know, I was doing adhesive dentistry. Never heard the concept of C factor, never heard about it. When he did it, he gave me a reference. I started to do a literature review, on those references. We had, the Journal of Operative Dentistry was available to me at ultra. Dent had a library at that time, and I, researched the original papers from 1984 and 1987, from Carol Davidson. And all of a sudden, C factor was very important because it had to do with this stress to the hybrid layer. Now, in those days, the bonding systems that we had, well, that were investigated in the mid 80s who were part of this group, but the systems that were used were not the three systems that survived in 1980s. The systems that were tested, were very early testing that on a flat surface, these bond systems could only get about 19 megapixels. Now, the bonding systems we have now, flat surfaces can get 50, even 60 mega pascals triple that amount. But these early testing of the bonds on these flat surfaces, all of a sudden, when they started to incorporate a cavity which is like a tooth, normal situation, a class one or class five, Harold Davidson and his team found out that about 19 mega pascals, you could not keep your bond in a 3 or 4 walled cavity configuration, or the C factor of three or above was too much to keep that bond strength. If it started at a 19 potential on a flat surface. Well, as time goes on, and this is the 80s, and now I'm in the 90s studying and we're improving, bonding systems. And now, five years after I started Adhesive dentistry, I came to be mentored through the literature by doctors out of Japan who had now shown that these systems are having double the bond strength of traditional adhesive systems. And so in 2000, the theoretical concept that came out of Tokyo Medical and Dental University is that these adhesives now have such improvements, and they're near the strength of the DNA in a natural tooth. Again, this is on flat surfaces, so they're not theoretical Li into C factor at this time. In fact, they were kind of resisting it. The Japanese had the idea to build a strong enough bonding system. They need not to worry about these confusing ideas of the ratio of bonded to bonded surfaces. I can see that dentists want easy. Dentists aren't smart. Is that what we're saying? You know, I had a science background. I had a chemistry minor. I had a microbiology major. Science was not. I was not afraid of science. I just went to dental school thinking, there's not much science here. There's a lot of hand and eye coordination. You have to be able to do things. It's more like a sculpture class than anything scientific. But now you know, I'm out of dental school almost 20 years, 17 years. I quit dentistry out of frustration of the traditional mechanical approaches and the early adhesive approaches in the 80s that I tried products, you know, promised my 3 a.m. that these are great systems and they were not great system. They were not good. I just wasted money, you know, for basically ten years. But with the improvement of materials and the improvement of understanding the science, then all of a sudden it came to me that there was the ability to start using composites in the posterior. And my second serious mentoring piece of dentistry, Gary Hunter brink, had some techniques, that he, taught me and some techniques that he didn't teach that were inspirational to me to try to find out the answers, which I did. But as I talked to Gary and to bring in 1998, 1999, 2000, then these ideas of polymerization dynamics being the key to understanding how to keep the hybrid layer from being stretched in Denton. That's an important concept you've never heard before, unless you've been taught by me. Nobody's ever talked about a hybrid lane being stretched during its polymers phase, but when I understood that that was what caused weakening of the Denton hybrid layer before it failed, then preventing the stretching of the hybrid layer during the polymerization reaction became key to maintaining its strength, and for having the longest sustainability. The longevity of this restoration. And then in 2002, I would say maybe one of the top ten of all time dental papers was published out of a combined effort from Germany, Japan and the United States. My third mentor in adhesive dentistry, Charlie Cox, was part of that team. And in 2002, they published this paper that compared see factor, hybrid strength and bonding systems, direct versus indirect. And the lead author was Toru Ni chiro, a friend of mine, one of the first PhD students under Takami and Toro ni Kaido. When he published his paper I thanked him personally for the effort he did. It was a team effort. Doctor, Councilman from Germany, Charlie Cox, United States. I think Doctor Watts from England was on that paper also. But they found out that with C factor, you do a direct composite with a two millimeter or even a bulk fill technique. You're going to lose half of the bond strength. In other words, if you have a potential, 50 or 60, you're going to be down into the 20s. And that was just right off the bat. But then what they did in this test is that after they tested, the bond strength, then they had another group of samples that were restored. The same way, and then they put them in a Turing machine, and there's two a machine with thermal cycling and actual forces of chewing came up with these stretched hybrid layers, these weakened hybrid layers. It lost 50% of its bond strength. You know, within the first year, for sure, under function would lose another 10% of their bond strength. And then they had the other group that they tested that they allowed the immediate didn't sealing and resin coating before an indirect restoration was placed. They let it mature and when it matured, and then they placed the in direct restoration and pulled that apart. Then it doubled the bond strength. It got into the 40s. But the great thing was they had this other group of these. I mean, you didn't see it in resin coating, indirect only or inlay restorations, then this group, they fatigued. Now the group that was done without this stress control that lost half of its bond strength immediately and then under fatigue lost another 10%. The group here not only had a double bond strength immediately with this approach, but under chewing fatigue of 10,000 cycles, they tested the bond strength. It had no decrease in bond strength. That's hugely important. So if you don't stretch the hybrid layer in the first 24 hours. Then you have the ability to have a hybrid layer that is now as strong as a natural tooth without fatigue. A natural tooth doesn't fatigue unless it has some type of crack into the den. Okay, so 2002 Nakamoto published the paper. Of course I go to dental conventions, doctor dentists. I go to meetings, I talk to dentists, I talk to my friends. I talk to my friend. Nobody knows any of this stuff. I've been studying it for seven years. I've got to figure it out. I basically been doing the six lessons approach for three years in my office from 99, when a gold standard body system was introduced in the United States market. Gold and C bond, information about the activating MPs came out, a couple of years later. Anyway, we put it all together and all of a sudden you restored tooth. No sensitivity. You restore it to five years is still fine. Ten years still fine. Now 15, 20, now 25 years. We're going into restorations that are just fine. In other words, they're acting like a tooth. They're connected side to side, front to back, top to bottom, with the same connection that an actual tooth has, which is someplace within 30 50 Mega pascals. Sounds easy, but you have to learn it. And we are going to invite all of you to learn that. And many opportunities are around the world. You can come to pro will get trained, you can go online, get trained or mastership, which is really our flagship, we want you to have the same success these hundreds, even thousands of dentists are having now, using the six lessons approach to biomimetic dentistry. And so, until next time, get bonded, stay bonded.