Zirconia Resin-Bonded Bridges, Air Abrasion, and Pre-Orthodontic Bonding with Dr. Bill Robbins

Dr. Bill Robbins: So my job is to make the teeth correct, the orthodontist's job is to make them fit together. And so we talk a lot about this today, and this isn't the standard in dentistry. Most people aren't doing this yet, but it's our goal to move dentistry in that direction, because I believe it's the only way to predictably get the teeth in exactly the right position that we need them to do a restorative dentistry at the end.

Dr. Melissa Seibert: Hey, welcome to Dental Digest. I'm your host, Dr. Melissa Seibert. This is a podcast with a mission of enabling you to stay on the cutting edge of evidence-based dentistry.

My guest this week for our two-part series is Bill Robbins, and he's going to be giving a sneak peek to an upcoming course he'll be teaching with his colleagues Marcela Alvarez and Brad Breckle. This episode is part two of two. In this course, as well as in this episode, you're going to learn a systematic approach to treatment planning, aesthetic crown lengthening, a concept known as pre-orthodontic bonding, dental photography, and more.

To learn more than what you're learning on this episode, go to stonercosmetics.com. The course is October 25th through the 26th and November 15th through the 16th. And by the way, if you enjoyed this podcast and want to continue to enable it to be around for years, please leave a rating and subscribe on the Apple Podcasts app, Spotify, or wherever it is you get your podcasts and share this with your friends, because sharing is caring.

Welcome to Dental Digest. This is a podcast devoted to following evidence-based dental literature. Here's your host, Dr. Melissa Seibert. She's a dentist currently practicing in the Air Force. With that being said, nothing contained within this podcast is intended to be reflective or endorsed by the U.S. Air Force.

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Dr. Melissa Seibert: You know, it's interesting, I'll just say this, and again, I think people are welcome to disagree with me. I think some people will say that you can't actually bond with zirconia because it's micromechanical retention and therefore it's not bonding, but I would really disagree with that because if you think about it, the majority of enamel bonding is micromechanical retention. In fact, that's virtually the most reliable bond that we have.

And so, I mean, take that for what it's worth. I think, to me, it seems like in 2024 with evidence-based dentistry, we can predictably bond with zirconia.

Dr. Bill Robbins: I totally agree. I mean, literally there is, as commonly as the case, the European restorative dentists when it comes to adhesive dentistry are ahead of American dentists. And they've been doing bonded zirconia bridges within the high 90% success rate for 20 years in Europe.

So anybody that tells me you can't bond zirconia in the mouth is just not paying attention to the literature. You can absolutely bond zirconia in the mouth long term. I don't care whether it's micromechanical or it's chemical or it's a combination. It doesn't make any difference to me.

You must follow the rules, and the rules are about thickness and preparation and also bonding. I mean, we should probably talk a little bit about that because my bonding protocol has changed over the last several years.

In the old days, we all know that salivary pellicle or protein inhibits the ability to bond zirconia. Everybody knows that. We knew that you had to use some material like Ivoclean or Katana to clean it off, and then you could bond it. However, a study came out about three years ago that talked about air abrasion.

And once again, pretty much everybody agrees that air abrasion is an essential step. But the important thing about this study was is that I used to depend on the air abrasion that the lab did. So the lab would air abrade it. They would send me the case. It might sit in the box for a week, and then I would try it in. I would put the Katana or Ivoclean on it, clean it off, and I'd bond it.

Well, it turns out that we must air abrade it just before we bond it. So the very last step before we bond zirconia restoration is it should be air abraded and then cleaned because it changes the surface energy of the zirconia. And so my protocol has changed today.

I try it in. You can clean it with Katana or not. It doesn't make any difference. You go in and air abrade it 10 seconds, 10 millimeters, 25 psi, just as a rough rule. So it's real air abrasion, and you're making sure you're getting all the intaglio surface of the bonded bridge. You clean it off, and you bond it.

So that's another step that changed for me in the last few years, and that's the knowledge that we've got to air abrade it just before we bond it.

Dr. Melissa Seibert: Do you want to say those parameters again one more time for the distance?

Dr. Bill Robbins: So the tip of the air abrasion unit, it should be 50 micron alumina, first of all. The tip should be 10 millimeters from the surface you're air abrading, and it should be for 10 seconds.

Dr. Melissa Seibert: Okay, 10 seconds, 10 millimeters, 50 micron alumina, and 25 psi is about 1 to 2 bar. 25 to 50 psi, 1 to 2 bar. So 50, 10, 10, 1 to 2 bar pressure.

Dr. Bill Robbins: Yep, right, right.

Dr. Melissa Seibert: Let's just recapitulate that because that's really important. I think a lot of people are just heavily reliant on the cleaners to clean the zirconia.

So just like we talked about, salivary proteins, just debris from the mouth has a high affinity for zirconia surface. And so having it clean is critical, but a lot of the way that people were cleaning it is that they were just using things like Katana cleaner, Ivoclean, but that's not enough.

And in fact, you're spinning your wheels as well if you're properly air abrading it right before delivery. That's just an unnecessary step. But exactly like you talked about, and I think this came out of T. Seara Solomon's lab, you as the provider should be the one air abrading it right before the delivery. Don't have the lab do it. And that's what so often is happening though.

Dr. Bill Robbins: Yeah, that's exactly right. And I think for completeness sake, we ought to say one more thing, and that is you should never air abrade e.max. Don't get e.max confused with zirconia.

It's a totally different product. So that's not our subject today. We're not talking about lithium disilicate, but don't think that if you're air abrading zirconia, it's okay to air abrade lithium disilicate. It is not.

Dr. Melissa Seibert: I think the more the podcast has evolved, I would say there's fewer and fewer things I would say are never, but glassy ceramics. So that would include your feldspathic porcelain, lithium disilicates. So e.max is one. LiSi, another one on the market. Those should never be air abraded. You're creating just micro cracks, whereas zirconia has its own properties where it can readily withstand the insult from the air particle abrasion.

But even, I think some people will that are maybe kind of the CEREC docs that are doing CAD/CAM dentistry and they are staining the e.max, some will advocate for just, you know, air particle abrade the facial surface a little to roughen it.

Dr. Bill Robbins: Bad idea. Don't ever do that.

Dr. Melissa Seibert: I agree. Do you want to go through the rest of your protocol? Because the air particle abrasion for preparing zirconia for bonding, that's just one step. I like to use the APC acronym.

Dr. Bill Robbins: Yeah. Do you know who wrote the APC article?

Dr. Melissa Seibert: Markus Blatz.

Dr. Bill Robbins: Yes. Do you know who the second author is?

Dr. Melissa Seibert: Marcela.

Dr. Bill Robbins: That's right. Marcela Alvarez, my partner, was the second author on that very famous paper and the case that was shown in the APC concept was her case.

Dr. Melissa Seibert: Marcela is the best.

Dr. Bill Robbins: Yes, she is. That's my partner, Marcela. Well, so the first thing I do is try in the bonded bridge and make sure that it fits.

The next thing I do is I go back to the lab and air particle abrade it. 10 seconds, 10 millimeters away, 25 psi, 50 micron alumina. All right. 10 seconds for that. I wash it and dry it. You don't have to do anything else.

I then come back to the tooth. I pumice the tooth. I etch the enamel. I wash it and dry it. I happen to be a Panavia user, and you can either use Panavia V5 or Panavia SA. They either do beautifully.

If I'm a Panavia V5 guy, because I'm just an old fashioned guy, I like the multi-step product rather than the self-adhesive product. So if you're using Panavia V5, then I'm going to put the ceramic primer on the intaglio surface of the wing. I'm going to dry it.

I'm then going to put, after I've etched the enamel, the tooth primer on. 20 seconds, air dry it. I'm going to mix up, or not mix up the cement, just squirt it out of the tube into the wing and put it to place.

If you're using another really great product, a 3M product, I have that in my office also. So it's a similar thing. You're going to etch the enamel. You're going to place Scotchbond Universal on the tooth and on the intaglio surface of the zirconia, and then you're going to use RelyX Universal Cement. So those are my two primary products that I use.

If you use a single step product like Panavia SA, then it takes one of the steps out. You don't have to put the primer on the tooth. It still probably makes sense to put the primer on the ceramic. You don't have to put it on the tooth. So what the key is, you have to understand the product that you're using and follow the directions of the product that you're using. That's the key issue, I think.

Dr. Melissa Seibert: I'm going to go on the record. And again, there's very few always, but I will say that if you are doing adhesive dentistry and you're bonding to enamel, to this day, phosphoric acid etch to enamel is still the gold standard.

So I have some thoughts on something that you said, but when it comes to phosphoric acid etching enamel, some adhesives might be a universal adhesive. So they'll say kind of all-in-one chemistry, still need to do phosphoric acid etching as well with the cement. So Panavia SA stands for self-adhesive. Even though they might say it's optional, you still need to phosphoric etch the enamel.

Dr. Bill Robbins: For sure. Absolutely. You got to etch enamel 100% of the time, period.

Dr. Melissa Seibert: People are going to be listening to this and think that you agree with me this much. This is not reality. We're living in an alternate reality. Most of our conversations, you're disagreeing with half I'm saying, which is very healthy.

Dr. Bill Robbins: Yeah, you and I disagree on a few issues, but mostly we agree.

Dr. Melissa Seibert: Make it known you don't think this highly of me.

So one other thing too, you know, speaking of agreeing or disagreeing, Panavia SA is a phenomenal cement. Panavia SA is not the only self-adhesive on the market. For me though, typically, if I'm very reliant on adhesive dentistry, so perhaps a veneer, an onlay, resin bonded FDP, I tend to use the adhesive cements, not so much the self-adhesive cements.

Dr. Bill Robbins: Well, I'm in total agreement with you. I just don't really see the real reason that people are so enamored with self-adhesive cements because the literature is clear they're not as good as the multi-step cements.

However, I'm friends with the chemists at Panavia, at Kuraray, and I was in Chicago with one of them recently. And I don't think this is necessarily true for other self-adhesive resin cements. So I don't think this is necessarily true for, for example, the 3M product to say that it's as good as universal. I just don't believe that's the case.

But in terms of the Panavia chemistry, they tell me that bonding zirconia with Panavia SA is equally as efficient or as good as with V5. So that's what the chemists say. I am very happy with V5 because I've got 10 years of success with it. And when you're successful with a product, why change? But in that specific chemistry, they will tell you that SA is as good as V5. I don't think that's necessarily true for other products.

And I agree with you. And in fact, I still am not using SA in my practice. I'm using V5 because I believe in the multi-step products because overall the literature is very clear. They do better than the self-adhesive resin cements for sure long term.

Dr. Melissa Seibert: That's fair. And that's not to say that self-adhesive cements don't have a place. So perhaps if I'm cementing a posterior crown, maybe we've got 2.5 to 3 millimeters axial wall height, I'm a lot more comfortable using a self-adhesive cement.

It's just, I would really caution anyone that's using a self-adhesive cement and they're cementing someone's veneers a week before that person's wedding. You know, they might be calling you, yeah, probably not the last week, but maybe two, three months later, they might not like you so much.

Dr. Bill Robbins: Yeah, I agree. So I'm just not a self-adhesive guy. But cements are certainly confusing.

Dr. Melissa Seibert: So if anyone's listening to this and they feel confused, don't worry. I think 90% of the profession feels very confused about that. I briefly wrote an article on Spear Education going through different types of cements. It's free for anybody that wants to read it. Just Google it.

But yes, cements are confusing. And I think the marketing behind it makes it a little bit more confusing as well. So for anyone that's listening, but let me ask you this. You talked about really dialing in the occlusion. What are some occlusal mistakes in perhaps the patient's occlusal scheme, which could be overlooked and lead to early failure of the restoration?

Dr. Bill Robbins: So we're talking about now the bonded bridge?

Dr. Melissa Seibert: Yes.

Dr. Bill Robbins: Okay. So pretty simple for me. I'm fine having both MIP and excursions on the wing. And remember, the wing is primarily going to be on the canine in my world. I'm fine with them touching it in MIP lightly and touching it in excursions. For sure, I'm fine with that.

I want no occlusion on the wing. I want no occlusion at all.

Dr. Melissa Seibert: Wing? I'm sorry. Sorry. Pontic?

Dr. Bill Robbins: Thank you for correcting. I'm okay on the wing. I want no occlusion on the pontic. I don't want MIP on the pontic. I don't want excursion on the pontic. I want no occlusion on the pontic at all.

And the more vertical overlap there is, the more problematic it is to make that happen. And that's the reason I want to be involved with the orthodontist before the braces go on.

That's my plea to the orthodontist. Please involve me in treatment planning with any patient that's going to get restorative dentistry done at the end of ortho, whether it's a kid or an adult. I want to be involved in the treatment plan before the braces go on, because I want to have some input into how I want that occlusion to be set up orthodontically.

Unfortunately, that's commonly not the case. I'm not involved in the ortho, and I get what I get afterwards. If the patient has a deep vertical overlap, that's just a patient that's more likely going to have debonding over time.

But I'm going to do the best I can to keep all of the function off of the pontic, both in MIP and excursion.

Dr. Melissa Seibert: Okay. So deep bite patients, patients with excessive overbite, these are pretty like, I mean, this is a red light type of patient. You would not really want to proceed with treatment.

And you brought up a really important consideration. You know, there's kind of interdisciplinary versus multidisciplinary approach. I think a lot of people, unfortunately, don't have enough back and forth conversation with their orthodontist, but it sounds like you've got a pretty great situation with some of the orthodontists in your community, where it seems like there's a lot of extensive planning. You hopefully don't have too many surprises coming into your practice.

Dr. Bill Robbins: Oh, I've got lots of surprises coming into my practice because we've become a go-to place for the bonded bridge in San Antonio because most general dentists aren't providing that service.

And so we're getting patients from all over the place now. And commonly they're not set up for a bonded bridge. So no, it's not all dialed in. It's dialed in with my orthodontist. I work primarily with two orthodontists in San Antonio, they're partners and there's never a problem, almost never a problem with them because I'm always involved in the treatment planning before the braces go on.

But that's not the only people that come to see us. So yeah, we have to deal with the same problems everybody else does. And that is occlusion is not really set up for a bonded bridge.

But remember, if they're not set up for a bonded bridge, they're not great implant candidates either because the patient with deep vertical overlap and the tight bite is a terrible implant patient also.

So it's an unfortunate circumstance to have that patient come in at age 15, 16, they've been in orthodontics for six years, they end up with an occlusion that's not desirable and you just have to be honest and tell them what the issues are. And it's unpleasant for somebody that's been in orthodontics for a long time to tell them that the teeth still aren't in the correct positions to do what we need to do.

Dr. Melissa Seibert: That's fair. And so we're almost running out of time here, but something that you're also going to be teaching that you and Marcela, particularly Marcela, have done a fair bit of lecturing on is the idea of pre-orthodontic bonding. What is that?

Dr. Bill Robbins: So in the old days, and primarily I'm talking about the adult wear patient now, we do a lot of the adult wear patients in our practice. And in the old days, we would send the patient off to the orthodontist and ask them to intrude upper and lower anterior teeth. We're going to be doing veneers at the end. That would be the common referral.

So the orthodontist knew what we were doing, but that was only a word referral and it was two-dimensional. Well, what we've realized is that that's a terrible way to communicate with the orthodontist because there's essentially no way the teeth are going to be in the correct positions at the end of ortho.

So what we do today is pre-orthodontic bonding. And what that means is that any tooth that's going to receive a restoration at the completion of orthodontics is going to be made anatomically correct with composite before the braces go on.

Now there's some circumstances where we do intermediate bonding and that's when the ortho is done for maybe a year, the braces come off, we do the bonding, and then the braces go back on. There's some circumstances where we have to do that. But the primary way we do it today is pre-ortho bonding.

So if a patient's going to get veneers on six or eight upper teeth and six or eight lower teeth, we're going to make those teeth anatomically correct with composite before the braces go on. It's the orthodontist's job to make the teeth fit together correctly. So it takes all of the guesswork out of the adult orthodontic patient.

If we're doing 28 units and it's a wear patient, it's going to end up with 28 units. They're going to get 28 units of composite on their teeth before the braces go on. It's then the orthodontist's job to coordinate the upper and lower arches.

We've made the teeth anatomically correct. So my job is to make the teeth correct. The orthodontist's job is to make them fit together.

And so we talk a lot about this today and this isn't the standard in dentistry. Most people aren't doing this yet, but it's our goal to move dentistry in that direction because I believe it's the only way to predictably get the teeth in exactly the right position that we need them to do a restorative dentistry at the end.

Dr. Melissa Seibert: Can you explain then what are the consequences down the road if you don't do pre-orthodontic bonding?

Dr. Bill Robbins: Well, what I did in the old days is when the orthodontist would call me up and say, Mrs. Jones is about ready to be debonded, you take a look at her and say yeah, and I would get her in. I would do some quick mock bonding on the upper front teeth, you know, one or two upper front teeth, one or two lower front teeth to see if everything was in the right place.

It was never in the right place. So I would send the patient back to the orthodontist and I'd say, you know, I need you to do this and this. Six weeks later, she comes back again and I do another mock bonding and they're still not in the right place. And eventually we would give up.

So the answer is in the old days, even though we were telling the orthodontist what we wanted, it's not fair to ask the orthodontist to put the teeth in the correct positions in space because there is a very precise position where the teeth need to be and it's very difficult to guess where that is without any help.

So the answer is most of the time we would do restorative dentistry in compromised situations. Today, we don't do that anymore.

If we make the teeth anatomically correct and the orthodontist put them in the correct positions where they're coupled with good excursions and good in MIP, then all we have to do is exchange the composite for the final restorative material and everything is in exactly the right place to make that happen.

Everything we've talked about today, we've written articles on. And I would invite you to go to my website, robbinsdds.com, and those articles are all there for free download. I mean, it's easier to find them there than it is to go to PubMed for most people.

So the bonded bridge, the pre-orthodontic bonding, global diagnosis, aesthetic crown lengthening, I've done articles on all of those issues and they're there on the website to be downloaded.

Dr. Melissa Seibert: Thank you so much for coming on. So definitely go check out your course. It looks phenomenal. I wish I could be there. It sounds like really people are getting a taste of comprehensive, complex restorative dentistry and some of the principles we talked about. Do you have any closing remarks?

Dr. Bill Robbins: No, I mean, it's just, I feel so lucky to be able to still be doing restorative dentistry at this stage in my career and to be able to work with young, exciting people like you. That's what brings me great pleasure.

In fact, tomorrow is my day at the dental school. So on Tuesdays, I spend a day at the dental school working with AGD residents at our program at the dental school. So I still feel so lucky to get to do all that.

You know, if what I said resonated today and you want to do a hands-on experience on the website, at the top, there's a banner and it's got information about the course, how you sign up for it and the investment and all that sort of thing. So feel free to go and take a look at it and see if it resonates with you.