Overcoming the Most Common Pain Points of Bonding

You're listening to the Phil Klein Dental Podcast. So there's no doubt that we are practicing in an era where composite and resin technology continue to play a major role in restorative dentistry. And with that, the adhesive layer and our technique in handling the adhesive layer is critical for our restorations to stand the test of time. We also have to be very concerned with postoperative sensitivity, and we know that's directly related to our technique. So today we'll be talking to an expert in restorative dentistry. His name is Dr. Rolando Nunez. He's a practicing dentist and has published many articles on restorative dentistry in peer-reviewed journals. He's a great guy, full of enthusiasm, great sense of humor, really fun to talk to. He's also a consultant for Bisco in many ways with their adhesive and restorative dental products. So we're going to be getting some information out of him, and he's going to be talking about technique, postoperative sensitivity, bonding to zirconia, using a rubber dam, and a bunch of other stuff. So let's get started with this podcast, and I think we'll all have a lot of fun. Dr. Nunez, it's a pleasure to have you on the show. Thank you for the invitation, Dr. Klein. So you're a busy man. You're doing a lot of work with Bisco these days, which is fantastic. doing research and development, technical support, and doctors are tapping into your expertise with all sorts of questions they have with the new materials out there, including zirconia, which we'll be talking about today, and also, of course, bonding, which Biscoe is very involved with. So one of the things that's high on the list of pain points for the dentist is patient postoperative sensitivity. And we know that post-op sensitivity... can be attributable to a myriad of factors like malocclusion, periodontal disease with exposed dentin tubules and so forth. But another major culprit to all this is improper bonding technique. So what are your recommendations when it comes to bonding with the ultimate goal in mind of eliminating postoperative sensitivity when we're working with composite restoratives? Well, you know, you hit a point right there that is quite interesting. It's something that I've spent a lot of time researching. you know, as simple and quick as possible. And this goes along with my personal experience, my clinical experience of 24 years of practicing dentistry. I have found that every time, whenever I did some total etching technique, there were some times that I would face post-op sensitivity. As I did more research on this topic, I found out that I was maybe mismanaging the dentin after etching. I was not providing the proper respect to etch dentin, meaning that I would use a little bit of air. from the three-way syringe to remove the excess moisture. And this will definitely have an impact on collagen. It will collapse collagen and collapse collagen will hinder the ability of the adhesive to properly seal the internal tube balls. And this can lead to post-op sensitivity. I switched from total, and this didn't happen on every case. Okay, mind you, it happened. In few cases, but it did happen. And I talked to colleagues and they were all experiencing the same thing. Even though we were doing the same procedure or we thought we were doing it the same every single time. When I switched to self-etch, sensitivity was gone. It just disappeared. And self-etch, what it does is the material, the adhesive will bond. to the dentin, but it will not remove the smear layer, but it will have an impact on it by making it more permeable or partially dissolving it, but you don't open the dentinal tubules. That procedure on dentin, to me, was a game changer, okay? So self-etching dentin or using an adhesive that has the ability to perform self-etch bonding. is a very easy, straightforward way of just avoiding sensitivity at all. What you do on enamel is a little different now. I recommend when I lecture about this, the selective etch bonding technique, where you etch enamel with phosphoric acid, but dentin, you don't use phosphoric acid. Now, I want to make it clear that I don't say that phosphoric acid causes sensitivity. It is the mismanagement of that etched dentin after smear layer has been removed, after collagen exposure happens, and after dentinal tubules are exposed that can lead to post-op sensitivity. So in order to avoid all of that, you can actually bond today without having to remove the smear layer using a universal bonding agent, for example. And that is something that a lot of people that have switched to selective edge or self-edge bonding techniques, they have told me, hey, I don't experience sensitivity anymore. And to me, that's something that is quite interesting. And it's something that we should love. I think anyone who's experiencing sensitivity should look into this and maybe even try it to see how it works. And it is predictable. It is very effective. And it has shown good clinical performance over time. So let me ask you this, Dr. Nunez. There are dentists that have a technique where they etch the dentin, whether it's selective or total etch technique. They use their bonding agent and light cure it. And then they light cure two layers of flowable composite on top of that. And when that's done, They use their bulk fill composite restorative or they layer it in, whatever they want to do. But having those two flowable composite layers on top of the adhesive system really does a tremendous amount for minimizing or eliminating completely post-operative sensitivity. What are your thoughts on that? Well, you know, when flowable composites came out... back in the, I want to say in the early 90s, one of the things that flowable composites, one of the features that were being marketed to the clinicians was that because the flowable composite has a lower modulus of elasticity, it can actually create a layer that could mitigate the strain, the stress that is created by polymerization shrinkage. And polymerization shrinkage can actually create something that is called cusp deflection. And even though you can't see it, there is a lot of stress on that cusp. And that can lead to post-op sensitivity for sure. So this is a way to mitigate the post-op sensitivity that is related. to the stress or strain created by polymerization shrinkage. You can also do that by changing your polymerization technique using something like ramp cure or pulse delay cure. I mean, there are many different ways to mitigate that. But when you leave dental tubes open, your flowable is not going to seal it. You need to seal that with your adhesive layer. Like you said at the beginning, there is a myriad of different reasons why. someone can experience immediate post-op sensitivity. The one that you just mentioned, which is related to the stress due to a polymerization shrinkage, is one of them. Leaving dental trubles open is another one of them. You cannot mitigate both with the use of a flowable. But even if you use a self-edged bonding agent and you still have a lot of stress because of shrinkage, You can still have sensitivity and say, oh, the adhesive is not helping. Well, it's a little different now. So you have to combine a lot of different things in order to 100% avoid post-subsensitivity. You kind of answered my question. So the self-adhesive that you're talking about that seals the dentinal tubules handles that open tubule problem, but the shrinkage that might occur is mitigated by flowing in that flowable composite. over the adhesive layer and then now you you've really done just about everything you can with good technique to minimize the chance of post-opera sensitivity is that correct for sure for sure there's a little nuance there it's not the shrinkage dr klein it's the stress that the shrinkage creates right and in my in mind you um some composites can shrink, let's say 1.5%, and other ones can shrink 3%. But you can actually have a composite that shrinks less, but creates more stress on the structure. So it's not necessarily like the more shrinkage, the more stress. It doesn't work like that, unfortunately. Low shrinkage is something that is desired, but more and more, I personally look for low stress. But effectively, we're really concerned about a gap being created between the material, the restorative material, and the dentin. Because if there's a space there and you get leakage, stimuli is going to kick off the fluid in the tubules and you're going to have pain. So we really want to minimize any gap development, which is often caused by polymerization shrinkage slash stress, where the adhesion is undermined by the stress. Correct. And also, you need to be able, by using the flowable, you could mitigate the effect of that stress that is generated. Right. That's my point. I call it a security blanket. You're putting a security blanket on top of this whole thing. Yeah. And it takes two minutes more. And if you're using a very good adhesive system, and then you go ahead and do this security blanket, you're... just for two minutes it's so worth not having to worry about getting a call on sunday morning that you know that that do that you put in number two is killing me i can't even i was supposed to go to dinner tonight i can't go out what do i do and it's sunday morning and you're like oh my gosh uh the last thing i want is this post-operative sensitivity on this particular patient um Let's talk about something else for a second, zirconia. Now, zirconia is a very popular material. It's trending big time now. They're making zirconia that's actually very aesthetic. So the days of zirconia are just being used for cases where their only strength is needed. We also have the ability to make the zirconia restoration very thin because of its strength. So if we don't have a lot of room in our prep, we could use zirconia. So there's a lot of indications for it, and it's a great material. However, there are dentists that are not convinced that they can get good bonding to zirconia. So what is your thoughts on that, and how do you approach that question when dentists ask you, How do we bond zirconia to the tooth? Yes. There is a thought process that is still lingering in the air that you cannot bond to zirconia, for sure. Zirconia bonding is probably one of the hottest topics that we handle through our customer service system, whether it's phone calls, emails. There is an ask the expert. tab in our website at visco.com where you can actually ask your question, whether it is product related or technique related or whatever. Even if you are in search of the meaning of life, you can write your question there. It doesn't mean we're going to answer it, but you can write your question. That was my next question about the meaning of life. We'll get to that, Dr. Nunez. We'll get to that. We take every question extremely seriously. The whole zirconia ordeal, it's been going on for a long time and it's not looking like it's going to either plateau or go down. Nowadays, there is enough literature. It's not even opinions, but literature. There is clinical literature. It's not even benchtop or lab results. We're talking about clinical. performance that shows that zirconia can work really well and you can actually bond to it predictably. The problem with zirconia is that zirconia, I like to say, is very temperamental when compared to other substrates like Emax, for example, or metal, or just porcelain. Zirconia can be contaminated by saliva. In saliva, once it is in contact with zirconia, will react chemically. And it will just deplete what we like to call the bonding site. So now you are hindering the ability of either your primer or your cement or whatever you're using to bond to zirconia to actually work. So there will be clinical failure. And then, of course, the first thing that a clinician, will think is, well, you can't bond to it. Well, you can, but you have to be extremely careful when it comes to the process of trying and cleaning afterwards or sealing the zirconia substrate before trying. So there are many different protocols out there and different possibilities. It's not straightforward. So, you know, there's a lot of probing like... If you ask me personally, how do I bond to zirconia? I will ask you, do you have a sandblaster in your office or do you, is it the lab that does the sandblasting for you? That's the first question. That's a very important question. And then it's like, okay. You're going to try in the restoration. You need a cleaner. Do you have a cleaner, a zirconia cleaner? There are three cleaners in the market. There is one by Bisco called Zirclean, one by Curare called Catanaclean, and one by Ivoclar called Ivoclean. So you can use either one of those. The only difference is the delivery system and probably the price. But they all work the same. They remove the contaminated substrate. from the reaction between saliva and zirconia. And now you have a clean, pristine zirconia substrate with a lot of bonding sites available. And then you can use your MDP. That's the other thing. Do you have an MDP containing primer in your office? There are many out there. Z Prime Plus from Bisco, Monobom Plus from Iboclar, Ceramic Primer Plus by Curare. And there are adhesives that contain MDP, like... products, Scotch Bond Universal Plus, All Bond Universal from VSCO. I mean, there are so many. So I need to know what you have so I can provide you with a protocol. So it's not straightforward like bonding to other substrates. And that's why I think people get a little bit confused because they will hear something and they will be like, well, that doesn't apply to me. What do I do? I'm confused. Now, you know what? I don't want to do it. I don't want to deal with it. And it's discouraging, you know, to some extent. But it is definitely possible to do a very, what would be the term, a very effective bonding procedure to the zirconia substrate, for sure. So are you a believer that a dentist should stick to one company with all the different components of the bonding process, whether they're putting in Emacs, whether they're putting in zirconia? whether they're putting in porcelain-infused metal or maybe just an all-ceramic veneer. What are your thoughts about sticking with a particular system? And part of that decision, I think, is related to troubleshooting. So if a doctor calls you up and says, you know, I put this in, I did everything by the book, and the patient came in with this zirconia restoration in their hand, what are some of the questions you would ask that doctor about their procedures to troubleshoot what possibly... have gone wrong and how they would revise that technique so that the next time they do it, it won't happen again. What do you, what kind of probing questions do you ask in that realm? Well, you know, the first thing I ask him is, could you, you know, the first thing is walk me through your procedure. And he just walked me through your procedure. Let's be honest, you know. And then there's always going to be something weird, something off. Like, oh, I used, you know, hydrogen peroxide to clean the substrate. And you're like, okay, you're not supposed to be doing that, right? So right there and then there is a red flag. And then I would say, well, who told you to do that? Well, I saw an Instagram post. I heard it on a podcast. Some dude from God knows where said that he buys hydrogen peroxide from Walgreens and then he uses it to clean and it works. And you're like, okay. So it's very complicated to actually find out if the material is not working or... the protocol is not working based upon the little things and little nuances that every clinician will do. But in the grand scheme of things, I think that if you have a bonding agent from Bisco, if you have a zirconia primer from Ivoclar, and if you decide to use a cement from 3M and you know what you're doing, you can make it work. You can totally make it work. And the reason why you like the zirconia primer from VSCO is because you heard somebody talk about it. But then you like the cements from 3M because you like the viscosity or you like the shade or you like the syringe, the ergonomics, you know? So I don't think you should stick to a full system made by one company. You could. If the company offers a solution to bond to a specific substrate, there is less thought process because every company would provide with a technique card or some sort of journey map or something where you can actually, you know, just plug and play what you're doing, but what product you're going to be using for your procedure. But in the grand scheme of things, if you know what you're doing, you can mix and match and still achieve good bonding. But the most important thing is to try to decipher what went wrong in your protocol and to provide a solution to that and ask the doctor, hey, yeah, no, we're not using holy water to clean our zirconia. It's not going to work. We need to use something else. When we were in dental school, rubber dams were a mandate. I'm an endodontist, so for me, my whole career, I had to have a rubber dam on. Initially, I never loved rubber dams, but I got to learn how to put them on and love them more and more because it actually made my life easier as I learned how to use them properly on each case, which clamp to use. With all the bonding and adhesive dentistry we do today, I'm hearing that the rubber dam is on a comeback. It's starting to reemerge as a... protocol that really is necessary to accomplish the kind of adhesive procedures that we're looking to accomplish. What are your thoughts on using a rubber dam and how much does that really help the outcomes of these clinical procedures where adhesive dentistry is so important? Okay. So there is a twofold answer here. I haven't read any clinical. research that actually compares restorations with and without rubber dam and their clinical performance. So I cannot say that when you use the rubber dam, your restorations are going to be better when you compare it to not using the rubber dam. I don't think you can actually get up and say it. And maybe there is some research out there. I haven't read it, okay? And I'm trying to keep up. It's not easy, but I try to keep up. with the current research out there regarding restorative dentistry. That's it. I don't have any idea about implants or perio or any other area of dentistry that is not restorative. However, the rubber dam, first of all, will give you full control, right? You have a better view. You have contrast because when you put a rubber dam... is blue or that is green, you have contrast, okay? You don't have darkness and all sorts of shades of red and pink reflecting on the tooth. You can see if the tooth is dirty better. You can see if the tooth is moist or humid better. You have more control. By having better control, theoretically, your restoration should be better. Why is there a resurgence? There are many factors. A lot of people are teaching rubber dam in continuing education programs as almost being mandatory. Also... Klein, if you post a clinical case without a rubber dam on social media, you will be demolished by all the sleuths and the Instagram and Facebook and YouTube crowd, and you will be social media humiliated. Even though no one will know and you will still be by yourself sitting on your living room, you will feel half of the world is making fun of you. And, you know, public humiliation is one of the things that human beings fears the most. So there are a lot of reasons why rubber dams are picking up, you know. That's a good answer, good answer. Somewhat anecdotal, but until the research comes out where we can empirically say that rubber dams achieve better results, we have to stick to the anecdotal responses. And I think there were good ones. So let's talk about tack curing. How does that complicate the cleaning of dental cement, tack curing? Because you hear about that all the time. Yeah, well, tap curing, by design, some companies have developed products, cements, that you can tap cure for two to three seconds, and they will reach a gel phase. So now they have the texture. consistency is more like silicone. So you could actually cut it with a surgical blade, or you can just remove the excess with an explorer or probe or whatever instrument you have, and it's easy to do. The problem is that other cements are not developed to be tack cured. So if you tack cure a product that is not developed for that, it's gonna become hard pretty quick. And now that's gonna become an issue. Or if you tack cure for too long, now you have a problem because once the cement is hard, you are most likely gonna have to go probably with rotary instrument to remove all the excess. And now it becomes more complicated. Some people prefer to use to remove the excess while the cement's still in a flowable presentation. And that's okay. If you know how to do that, if you have a technique to do that, that's fine. I don't think one technique is better than the other. You just need to know for how long you have to tag cure. Well, first, if you're cement, you know. It includes in the IFU that you can actually tack cure. We, by design, at Bisco, develop every cement to be tack cured for two to three seconds. It is in our IFU, but it's very specific. You know, two to three seconds. That's it. You know, but we put it there. You choose not to do it. You don't have to do it. But by design, it is developed so you can do it. Okay. So is there a problem with this? Yes. Over curing, that's going to be a problem. And products that are not designed to be tack cured, that's going to be a problem. So would you recommend that to be on the safe side, don't tack cure and just do it the old fashioned way while the material is kind of fluidy, just use an Explorer and get the excess off and clean it up. Then you don't have anything to worry about. I know a lot of dentists do not tack cure because they're afraid they're actually going to move the whole restoration by. Once it gets hard, they're pulling at it and then they form a gap and it's no longer sealed. What's your feeling? Just stay away from tack cure other than reading the IFU diligently and subscribing to exactly the two seconds you're talking about. Otherwise, just go with the technique that we use in dental school. When in doubt, don't tack cure. Don't tack cure. If you are 100% shh, you know. certain that the IFU, because you read it, the IFU states you can tap cure for one to three seconds, two to three seconds, and then you can go ahead. One way, this is very, how do I say it? It's kind of like a dirty test you can do. I used to do this all the time. I had like microscope glass lights in my office. So if I wanted to know something, you can tack cure it. I will take a little bit of cement, put it between the two glass lights, press it, and I will have it ooze it out at the edge. And then I will hit it with a light for one to two seconds. And then I will feel it with an instrument. If it was like silicone, I can tack cure that guy. And then I'm like, okay, I can tack cure this. This is very empirical, but this is a way to find out, to make sure. But when in doubt, don't try it. It might get nasty. It's better to just remove the access and go, you know, move forward with your current procedure, you know, protocol, whatever it is. But if you can read the instructions and make sure you read that, TAC cure for this amount of time. And then you can do that to that product. I think we know, both of us, Dr. Nunez, that most dentists and most people don't read IFUs. They just don't. Some do, and they're very careful about it. But for the most part, we like to open up the box and start going at it and learn by... Trial and error. I'm one that actually reads IFU. I like to do that if I get a microphone for my podcast program just by setting it up or any kind of equipment or when I was practicing endodontics full time and I used a reciprocating handpiece by Kerr that was the old one that came out originally many years ago. I really enjoyed reading all of the issues because they tell you this is something to be aware of. Warning. Doing this could cause overheating. You could break this by putting the burr in in this direction while it's still running, whatever. You can break this. You can break your file. I mean, it's good to know these things when you're practicing dentistry. I mean, why not? It's always good to read the manuals. We're at the point now in dentistry, and I know Bisco is a leader in adhesive dentistry in many ways, but I think we're at the point in our profession that with good technique and the materials that are out there today that have been tried and true, We are at a point where we could obtain phenomenal bond strength, do some amazing things with additive dentistry with our composite restorative, and we can also minimize postoperative sensitivity by doing things correctly. And I always recommend companies, when we talk to other dentists about... you're buying products, work with companies that have technical support. Work with companies that you're able to call and get a human being on the phone that actually understands dentistry. You're one of them. If our listeners want to follow you for future updates on new product innovations, clinical procedures that are designed to achieve predictable long-term clinical success, what is the best way for them to stay in touch with you, Dr. Nunez, going forward? Well, there are a few things out there. The first thing that we have, and we have this for a while, is a very comprehensive amount of resources on our website, anywhere from e-books to podcasts to webinars. And there is that Ask the Expert tab on our website. So if you're watching a webinar and all of a sudden you have a question, you can go to Ask the Expert and write your questions, and we will get back to you as soon as possible. We also just came out with a podcast of our own. It's called Bonding and Beer. So half of the podcast is talking about innovation, is talking about clinical procedures. And those topics come from our frequently asked questions. So, you know, one episode we talk about sensitivity. Another episode we talk about zirconia bonding. Another episode we talk about bioactive materials. Half of the episode is about a clinical procedure, a specific topic. And the other half is about a beer that we bring as a guest to our podcast. We open it, we drink it, we review it. I've been reviewing beer for the past, I don't know, 10 years. And I have a long list of beer that I have had all over the world. And it's an interesting world. I enjoy it very much. So those are my two passions. Restorative Dentistry and Beer. So I put it together in a podcast and you can follow us on any, you can find us on any platform out there, Bonding and Beer. We're on Instagram also, Bonding and Beer. And we are on YouTube where you can watch episodes for free and you can subscribe and download the episodes like any podcast. So, yeah, we have that going on. Yeah. And the beer part, obviously, you want to do after the clinical part, because if you do the beer first, then you're giving this information under the influence of beer. And who knows what you're going to be saying, right? I mean, I'm saying tongue in cheek. You want to do the beer afterward. Dr. Klein, that's part of the allure of the episode. I start by opening the beer. I drink the beer as we go along and it gets rowdy at the end. Okay. All right. Well, we're looking forward to it. Thank you. It's another spin on doing a dental podcast because there are certainly a lot of dental podcasts out there. We've been fortunate. We've been doing this since 2018. I think we're on our 565 episodes. That is unbelievable. That is insane. When you add it all up, it's about 32, 33,000. listens per month and each individual episode is some of them are getting five six thousand listens which is a lot because it's you're talking about dentistry you know we're not talking about uh major league baseball we're not talking about politics we're not talking about beer if i talked about beer i think i could increase my uh but i'm going to leave that for you i'm not going to touch that Yeah. We're going to leave that to you. All right. Well, listen, again, I love the people at Bisco. You guys are a great company. We're very happy that you came on our show. Good luck with your podcast. And you really shared a lot of very important information today. And I hope our audience enjoyed it. Thank you so much, Dr. Nunez. Thank you, Dr. Klein. Thank you for the invitation. It's always a pleasure. And it's always super cool to talk to you.