The State of Adhesive Dentistry
Gerard Kugel, DMD, MS, PhD | Robert A. Lowe, DDS, FAGD, FICD, FADI, FACD | Lee Ann Brady, DMD
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The Roundtable is a forum for debate on key topics, trends, and techniques in dentistry. For each edition, a panel of experts will take on a subject to help expand your knowledge and boost your practice. This month, our panel of experts discusses adhesion; a portion of that discussion is presented here. Watch the whole conversation at insidedentistry.net/go/adhesionroundtable.
About Our Panel
Gerard Kugel, DMD, MS, PhD, is the associate dean for research and a professor of prosthodontics and operative dentistry at Tufts University School of Dental Medicine and the editor-in-chief of Inside Dentistry. He is in private practice in Boston, Massachusetts.
Robert A. Lowe, DDS, FAGD, FICD, FADI, FACD, is in private practice in Charlotte, North Carolina. He was nominated to receive diplomate status on the American Board of Aesthetic Dentistry, an honor shared by fewer than 50 dentists in the United States.
Lee Ann Brady, DMD, owns a restorative practice in Glendale, Arizona. She is the clinical editor of Seattle Study Club, and teaches at the University of Florida College of Dentistry. Her dental education blog is found on her website, www.leeannbrady.com.
Inside Dentistry (ID): Does etching with phosphoric acid produce more cold sensitivity than the self-etch technique?
Dr. Gerard Kugel (GK): I think the total-etch technique technically and theoretically could produce more sensitivity. The selective etch is not a bad way to go because you are etching the enamel if possible and then you do a dentin adhesion with your self-etching product. The problem with sensitivity when using the total etch with phosphoric acid on the enamel and dentin is often the operator—over-etching, not bonding the sealant and dentin tubules correctly, putting the right amount of material on, air thinning it too much, air thinning it too little. I joke in my lectures that if you look at all the ways you can make a mistake when you do adhesive dentistry, it’s amazing how things work out relatively well at the end of the game. It doesn’t mean you are going to get sensitivity, but it could mean sensitivity if you are not careful about how you do the procedure. The literature seems to indicate that some self-etching products will cause loss of sensitivity on dentin, but I still do an etch of enamel with all of my products.
Dr. Robert A. Lowe (RL): Dr. John Kanca really introduced us to the term wet bonding years ago. At that time, I was a full-time instructor at Loyola. I can remember one of the materials people there saying, “You know what? If we start etching this dentin, we are going to become the endodontist’s best friends.” That never materialized. I think Gerry is exactly right. When you have so many different variables, starting with a phosphoric etch, the key is the time element. Ron Jackson said in one of his articles in 1999, “The two main causes of sensitivity with total etch is over-etching, etching too long, and under-priming, not getting enough of the hydrophilic primer into the dentin to create a block of plastic dentin.” This is an exact procedure and too many dentists don’t take the time to do it by the rules. Sometimes we can get away with that and sometimes we can’t. I also agree with the selective-etch technique. I think that if you want to have the safest, best result, use the self-etching adhesive on dentin and augment the enamel etch with the selective-etch technique.
Dr. Lee Ann Brady (LB): Sensitivity for me is still the primary thing that I get asked about when I am out on the road lecturing or getting emails from dentists. Believe it or not, I get as many of those requests for people who are using self-etching adhesives as I get from those who are using phosphoric acid. I think it comes down to technique sensitivity. If you are not sealing the dentin tubules, if you are not developing what we called a hybrid zone, even with the self-etching adhesive, the follow-up consequences can be ongoing postoperative sensitivity for the patient. There are a few pieces of the puzzle that potentially create technique sensitivity when you are not using phosphoric acid. Even simple things, like not refrigerating the adhesive if it says to, not shaking the bottle if it says to, really paying attention to the directions to how long you should scrub or agitate the adhesive against the dentin. All of those things result in patients having sensitivity even with self-etchers. If you are struggling with sensitivity, regardless of your technique, what I would do is go back, really pay attention to the details, follow the manufacturer’s directions, make sure you are actually doing the steps in the way and the order described. That should solve the problem.
ID: What is the best definition of universal adhesives and when would you recommend using them?
LB: One of my biggest problems with the word “universal” is that we have not all universally decided on how to define it. From manufacturer to manufacturer, they use the term universal differently. One of the things that I coach dentists about is that a universal adhesive will probably streamline our inventory control and that means that your assistant has to be responsible for the expiration dates of fewer products, loading the operative tray with fewer products. It does not mean that it is a universal technique for all of the different applications or a universal set of directions. It doesn’t mean that it universally fills all your adhesive needs. As I said, to some manufacturers, universal means total etch or self-etch, but it doesn’t mean dual cure or light cure. Each uses that term differently. You have to be aware of the products that you bought and what that term means in that specific case.
ID: I often hear the term “all-in-one” as well. Dr. Lowe, why would you change to this type of system and what are some of the advantages and limitations?
RL: I think the main reason why people change is to make protocols simpler and increase predictability or efficacy. When using the term universal, Lee Ann mentioned self-cure vs dual cure. That is where the big controversy came up in having to have an adhesive with a self-cure activator because of the different chemistries between an adhesive that we would use and a dual-cure versus light cure situation. If we can simplify the procedure by having a chemistry that works in both situations, but not sacrifice the quality of the adhesion, I think that’s what the goal is in finding a “universal” material. It doesn’t mean that it is universally applied to every procedure and in every material. Sometimes I joke in lectures on how I long for the days when silver and gold were my only options, because they were predictable and the colors always matched. Today’s dentists are presented with a quandary because of the complexity of it all.
ID: Dr. Kugel, in your opinion, what is the future of adhesion? Is there something on the horizon?
GK: There are a lot of good products out there and I do agree with everyone on the panel. If everything were done correctly, we would probably have fewer problems. The NIDCR has data from 2009 to 2011 on their website. Some of the recent data shows the lifespan of posterior restorations is 5.7 years. When they published that, there was a call for grants and we were a part of coming up with new technologies to improve that. When you think about the fact that composites last 5.7 years, that’s sad. I don’t think it’s the composites. I think it is how they are being used and the bonding agents. In a perfect world, a self-adhesive composite is a bioactive restorative that integrates to the tooth structure. We have things that are in that ballpark, but they aren’t there. If you asked me 20 years ago what the ideal future would be, I would say the same thing—a self-adhesive composite that interacts with tooth structure that actually becomes a part of the tooth. I don’t know if I will ever see that. Today, I would be happy if people did it the right way with what they have in their hands. Down the road, when the three of us are sitting on the beach or wheeling down the hallway somewhere and trying to remember my name, I would like to believe that we have a bioactive, self-adhesive composite that integrates to the tooth structure. We have tested some self-adhesive products that failed, but they are prototypes. When I say self-adhesive, it is more than just self-adhesive. It integrates with the dentin.
RL: My future is taking a little seed, dropping it into the gum tissue, sprinkling a little water on it, and growing a new tooth. I don’t know if I will ever see that either. I think most of us, in our practice lifetime, would just like a tooth-colored material that is as easy to place and as forgiving as amalgam. That is really it and we are not there. It would be ideal if we had a material that we could use like a direct restorative composite that didn’t need an adhesive and we didn’t need to treat enamel and dentin to get adhesion and create a hybrid zone. You would just clean out the decay, put it in the tooth and have a good seal, good adhesion, and material that actually provide calcium and phosphate to rebuild the demineralized tooth because it is always under acid attack. There are always materials that do bits and pieces of that right now. It is just finding one that does it all and does it predictably and easily. That’s the future if we could find a way.
LB: For me, to sum up what Gerry and Bob had to say, we want a tooth-colored, mercury-free, fluoride-releasing amalgam. Someone make that.
View the entire discussion at insidedentistry.net/go/adhesionroundtable.