Running Time: 34 min
Clinicians and dental technicians have access to an astounding array of new technologies, tools and materials to design predictable beautiful smiles. This presentation puts an emphasis on a close co-operation between prosthodontist, periodontist, implantologist and dental technician. In addition, a focus is placed on different surgical, clinical and prosthetic techniques to achieve successful aesthetics. Material selection is fundamental in management of complex rehabilitation and on implants. The aesthetic outcome and the natural appearance of the restoration depends on the skills of the dental technician. Understanding of the gingiva of the dental technician will be explained to re-create in a two-way communication an aesthetic end result. New concepts and trends with focus on zirconium dioxide and its excellent long-term behaviour and extraordinary mechanical properties, will be discussed to realize predictable natural oral aesthetics around implants.
Release Date: June 22, 2013Subtitle:
Hello, everybody. My name is Luc Rutten. I am a master dental technician from Belgium. And I am a lab owner, together with my younger brother, Patrick. Our focus is ceramics. And today, we are recording from New York City. And I will get you into the lab now. So the topic for today will be zirconium dioxide. And before I start in presenting my work, I’d like to share with you a few words about what is important about zirconium dioxide. It’s new material, and in the past, I know we had a lot of chipping and a lot of problems. Now I’ll go a little bit in detail about the material, zirconium dioxide. So we all know that zirconium dioxide is a bad heat conductor. It means that it takes very slowly the heat of the ceramic furnace, and once it has the heat, it gives the heat very slowly off. It means we have to change a little bit our firing tables. So pre-drying we do longer, much longer than we did for porcelain fused to metal crowns. So we double. So we take 12 minutes. The heating rate will be not 55 degrees Celsius per minute but 40 degrees Celsius per minute. And then the cooling down phase in the ceramic furnace is very important as well. We cool down until 500 degrees, and we stay there for six minutes. And then the furnace opens. So this is to avoid chipping. This is to avoid cracks and tensions between the material, zirconium dioxide and the ceramics we are working with. So on the first, what we never do is sand blast or grinding. Sometimes we have to grind. And when we have to grind, we take diamond burrs without less pressure and water irrigation, which is very important to avoid micro-cracks which you can’t see, after grinding. They will develop later in the patient’s mouth. So to avoid this, water irrigation is very important. So in the beginning, one told that zirconium dioxides was a very opaque material. Of course, it is little bit more opaque, compared to aluminum. But we have a beautiful properties of the material, which I’m going to explain right now. So here you can see the first thing we do with zirconium dioxide, with a suprastructure, we put it into the furnace. We do a regeneration firing to have a tetragonal structure into a [? white, ?] monoclinic structure. Here you can clearly see that, after a thin wash layering– and this thin wash layering ensures the bond, the connection between zirconium dioxide and ceramics. This is a slide taken by [? Dr. Tolai. ?] And you can clearly see that we have to deal with a rough surface when you put it in or when you see this photo. This photo has been taken under magnification 20,000 or 10,000 times. You can clearly see. You can compare the surface with a blackberry. They are all little bubbles, and they are melting into the zirconium dioxide surface. One says we have no data. There are no articles. I think that right now we have tons of articles, and tons of examinations has been done with zirconium dioxide. So there’s nothing new now. I think that we are ready now to avoid chipping, and we have a fantastic material to work with. As you can see here on this slide, so we fire this melting layer at 970 degrees or, for bigger or huge suprastructures. 980 degrees Celsius. This is very important. Here you can see photos taken under magnification of 20,000 times or even less, 10,000 times. So it is our purpose to leave the zirconium dioxide untouched, which can be noticed on your left-hand side. When you start sand blasting or grinding with a diamond burr, you can destroy the beautiful properties of zirconium dioxide. So we don’t do this. We go right away and do the regeneration firing. Of course, here you can clearly see, sometimes we have to grind, but always with water irrigation. What you see here is the first wash layering. Just for the photo, we applied a little bit thicker that you can see the difference. So for the first thin wash layering, we are using liner. Liner is a fluorescent powder. Why do we take fluorescent powder? You can clearly see the teeth photos are taken under ultraviolet light. And you can clearly see that the coping shows a shadow. And exactly this shadow, we try to avoid. So a beautiful study has been done in the past, as you can notice, about the fluorescence, the importance of fluorescency. You can clearly see– this is another case– what the meaning of the fluorescence is when you take photographs under ultraviolet light. You can see that the restoration brightens up. And after placement in the patient’s mouth, it brightens up the gingiva. And the gingiva is most a very critical area. A lot of studies have been done, as you can notice, concerning the fluorescence and the bounce between the material, zirconium dioxide, and ceramics. Why do we need a fluorescent powder now for the first thin wash layering? It’s obvious. You can clearly see these are cross-sections of natural teeth. And you can see that the dentin fluoresces a lot. So we, as a dental technician and as a ceramist, we try to copy nature as good as we can from the start. And the start is here, right on top of the basic material, zirconium dioxide. So we have a certain kind of protocol in the lab that nothing goes wrong or that we can avoid problems in the future. So this is a simple case I like to present just to show you how we work in the lab. First of all, there is a color communication. So we have clients or clinicians, they have their practice abroad. So this is the kind of communication we have. They mail the photos, so we can judge what to do, the basic color. So we also, we work a little bit old fashioned. On your left-hand side, you can clearly see galvanized dies or silver-plated dies. It’s an old fashioned technique, but it makes definitely sense to do it. It’s very precise. You never have bubbles, and it won’t break during working. So I have two models. The second model is an unsowed master cast to control the contact surfaces. So this is the provisional. The provisional is very important. So we make two silicone indexes. The first one will be a buccal one or the labial one for the coping design. And the second one is an incisal one. We need the incisal one for the position of the teeth, of the crowns, afterwards. Here you can clearly see what the meaning of a silicone index is. Without the silicone index, it’s hardly to judge how much do you have to double skin or how much do you have to build up the crowns, the copings. This is the second silicone index. This is the incisal one. You can clearly see, when we close the articulator, here we can clearly see where the position of the crowns will be after applying or after glaze firing. It’s very important. Here you can see the scanning procedure. First of all the copings or the crowns, the dies will be scanned. And then, of course, on your right-hand side, you can see the copings ready after scanning. And you can see how much we have to built up the copings to ensure the longevity of the restoration. So we have to build up that much to have a sufficient support of the ceramics. And of course, we have different, new powders as you can notice here. We have fluorescent powders. We have opalescent powders here. Opalescence is limited to the incisal edge. It’s an enamel effect, what you can see here. So in nature, of course, you can see that opalescence is limited to the incisal edge. So this is the first firing. And the first firing, we control on an unsowed master cast. Why an unsowed master cast? Because a sowed master cast, the dies are always a little bit moveable. So to reduce chair-side the work of the clinician, so it’s better to deliver these kind of restorations on an unsowed master cast. He can pick up the crowns and insert them directly without having problems with the contact surfaces. After glaze firing, of course, the crowns will be placed in the patient’s mouth. And you can clearly see here we touched very well the value. The value means the percentage of white in a certain color and, of course, a little bit of a life-like incisal edge. This was for young lady, so the papillas were not huge. She had small papillas. So we can see, if you can match the shape and then the position of the teeth, you can clearly close, and you have will have very female crowns. Notice here we have to deal with a fine structure ceramics, and you will see that we have a very, very homogeneous surface of the restoration. Here, once again, in close up, the restoration of the four crowns. So this was just to show the protocol we have in the lab to ensure the longevity of the restoration. So why have we chosen for a metal-free restoration? It’s very obvious. So we try to copy nature as good as we can. And you can clearly see in transmitted light of these extracted teeth, the cross-sections of extracted teeth, that there is a light transport in the teeth. So this is what we want to have for our copings. In the middle or in the center of the screen, you can clearly see this is a natural root and, on top of it, a zirconium dioxide coping. And you can see nothing blocks the light, and this is exactly what we want to have. So before we go into this second case I want to present, I want to share with you a few details– not details, but things that are very important for us. In the beginning, we only had white zirconium dioxide. And for a dental technician and as a ceramist, when you hear white or you see white, the alarm bells directly go off since white is considered synonymous for opacity, which it’s not. And now we have four different shades in chroma, as you can notice, and it helps us a lot, especially when you don’t have a lot of space. Now in our daily work, what is very important now concerning the material zirconium dioxide? First of all, it has a beautiful semi-translucency. It has translucency about 48%. That means that 48% of the light in the back is going through. As you can see here, side by side, a zirconium dioxide small BIB, and on the right-hand side, a cross-section of a natural tooth. So the second thing which is very important, I think, is a flexural strength of about 1,200 megapascal. It means that we can do large bridges, as you can see here on this slide. Can we do aesthetics? I think that we convinced you in the previous case. We have definitely a good aesthetics with zirconium dioxide, and the material itself, it’s good for the gingiva. As you can see here, it’s a very biocompatible material, and there is gingival adhesion. So I want to share with you the highway to success. And I clearly refer here to the AC/DC song, “Highway to Hell.” It could for you be a highway to hell if you’re not knowing what you’re doing. So it’s a fantastic material, but it can be dangerous if you’re not knowing what you’re doing. You have to understand the material. Then it’s no problem at all. This is the next case I want to present. It’s a bigger case already. It is an upper jaw, as you can see here, a full arch that we are going to restore. And the problem here is– although, for us, it’s not a problem– that the clinician couldn’t install implants at the height of the 21 and the 22 because there was no sufficient bone. So he did a soft tissue graft, soft tissue management, and he prepared for ovate pontics. And I will show you what we as a dental technician have to know about ovate pontics. What you see here is a master cast of the provisionals. So this we use for the cross-mounting. We put it into the articulator. And as I mentioned to you before in the previous case, so we take indexes. Here you see the incisal index, which is important for position of the teeth. And of course, we have a labial index as well. This is the scanned bridge. You see it in two parts. And we carved a little bit in the plaster to copy the cervical area of the opposite side. So here we can clearly see, when we put the restoration of the crowns and bridges on top of the silver-plated dies, we close the articulator, and you will notice that we have sufficient space for veneering material. So this is the protocol we have. Once again, the first thin layering ensures the bond between the zirconium dioxide and the ceramics. We take fluorescent material for this. So here we can see we fire very high, that it melts into the zirconium dioxide. And then it’s time for a little bit detailed work. Here you can see the applying of the front. You can see the layer of the mamelons and the blue, which is the opalescence what we see stratificate to reach a restoration which is as natural as possible. After a few firings, you can clearly see that we control the bake on an unsowed master cast in the articulator as well, upper and lower. We control once again in the articulator where the position of the restoration is. And you can clearly see we are not coming out of the arch of the temporary restoration here. Here, this is a little bit how we work with Dr. Gamborena. Once in a while, we are in his practice in San Sebastian, Spain. And there, we see the patient, and we can do minor corrections in the dental laboratory. This was the main aim, to get symmetrical gingival contour, as you can see here, in a bisque bake. So this is a mirror imaging of the cervical contour. And you can see that we are not far from the truth here. You can see we copied as good as we can. But you see you will notice that a little bit of the papilla is missing, which is sometimes typical between two implants. This is then the restoration after glaze firing. So we stain just a little. bit. Don’t exaggerate with stains, because they are pure metal oxides, and they can block the light. So I told you before what is an ovate pontic or what should we know as a dental technician about an ovate pontic? An ovate pontic, first of all, we need a preparation from the periodontist. I told you before, Dr. Gamborena did here soft tissue management with a graft So what we do is this, the correct shape here. This is an extracted tooth, and we cut of the root and all its mesial, distal, and palatal aspect. You can clearly see this is the basal from the basal site, the ideal shape of an ovate pontic. The purpose of an ovate pontic is that it comes out, like a natural tooth, out the gingiva. It’s easy to clean by means of [? silver ?] floss. It means that the basal surface of the ceramics will be polished in a very smooth away, as smooth as a wine glass. So here we see the situation in the patient’s mouth. All the abutments are on top of the implants, and you can clearly see how, afterwards, the ovate pontic will come out of the beautiful prepared gingiva. It’s not a new technique, as you can see. When you go into the literature, you can clearly see that David Garber and his team, they published already an article in 1981. And this is the restoration placed on top of the implants. You see, the purpose is that it comes out as a natural tooth. It’s easy to maintain, and there are no phonetic problems. Imagine when you don’t have a well-prepared gingiva like this, the patient will have phonetical problems, problems to maintain the restorations, and it doesn’t look nice because, most of that, you will have a retraction of the gingiva. And I know, in the past, we tried to cover this with a little bit a root imitation, which doesn’t look nice at all. So this is the next case I want to present. And you’ll see this is a tremendous gummy smile. And she was wearing old, opaque, porcelain fused to metal crowns. So this was the treatment plan, a few extractions and inserting a few implants in upper and lower jaw. So the first steps of the clinical treatment was to do a crown lengthening because she had the tremendous gummy smile. And then the second step was an orthodontic treatment, an intrusion. So here, you can clearly see the beginning of the treatment on your left-hand side. The old crowns were a little bit squared, and that doesn’t look nice. Triangle is better. It’s more feminine. It looks nicer, and it was a purpose. On your right-hand side, you can see the provisionals. These are the master casts. As told before, we like to work with silver-plated dies. And you will see, we have produced here a few zirconium dioxide abutments on top of the implants. This is more or less the ideal shape we are dealing with. One should come out of the implants like a wine glass– very thin, no much pressure on top on the gingiva. This is what our clinicians are asking. But Dr. Gamborena made our life a little bit easier. The main problem of a dental technician is, when the impression is taken with a regular, standard impression coping, then we have to carve a little bit to have a better aesthetic outcome. But the question is, how much do we reshape the gingiva? Too much pressure will result in an apical shift. So I think this is the best option we can have, that a clinician fills the sulcus with a composite, as you can see here. Then we pour the impression. And then, of course, we have the ideal outcome– so no doubt about this. Once again, sometimes we have to polish. There’s a lot of controversy about the shape underneath the abutments. What are we going to do with the zirconium dioxide? Do we polish, or do we leave it untouched? There are so many options. In this case, we polished. Zirconium dioxide is a material which can be polished in a very easy way. It’s much softer compared to aluminum. So we don’t have to invent something. A natural tooth get lost, so the implant will replace the root. And on top of it, we make a crown. It’s not more than this . You will see, in this case, it was not an easy case. We need the right information from the clinician. It means we need the midline in these kinds of cases and the horizontal plane. When we don’t have this, we have a serious chance that, afterwards, the crowns will be not in the right position in the patient’s mouth. As you can clearly see here, the gingival line goes a little bit down to the left side. So when you put it in articulator without this information, we definitely will have some problems afterwards. Then, of course, this is the protocol we have in the lab. You will see here this is the labial or buccal index to design the copings, to ensure the stability, to ensure that the ceramics will be supported enough by the zirconium dioxide copings. And this is a little bit the language Dr. Gamborena is using on the left-hand side with this mark that he marked there. And it means that we have to push up a little bit the gingiva. It means, as a ceramist, that we have to build up a little bit thicker in this area to push the tissue a little bit higher. On the center of the screen, you can see, when you close the articulator, you can immediately see where the restoration has to be after glaze firing. This is having a protocol. It’s like an architect. You don’t construct a building without the plan of an architect. So this is the plan of the architect. Here, this is the way how we deliver the work. In a bisque situation, it goes to the dentist for a try-in to control the, for instance, the horizontal plane, the occlusion, articulation. Then you we stain a little bit. And this is then the work after glaze firing. I was talking about contact surfaces. I don’t talk about contact points. You have two contact points when you put two tennis balls next to each other. You can’t do this in restorations because it will result in a big black triangle ideal for food impacting. So we love contact surfaces. Here you see on top of the implants that the abutments are screwed. And this is the restoration after placement, after cementation. From the palatal sides– even from the palatal sides, you can see that we have to deal with a very healthy gingiva. Homogeneous ceramics– which is very important because they’re cemented in a patient’s mouth, and they are supposed to be there for a very long time. So a homogeneous surface is very important. The close-up– you can see the final restorations. And the final x-ray fitting is always very good. It fits perfect. CAD/CAM is a wonderful instrument to work with. So the atlas of aesthetic implantology, the atlas means that we have to deal with big implant cases here. So now we go over to a full arch implant support. It’s a zirconium bridge. Often, colleagues are asking, how do you do this? It’s simple. The first step is to understand the material. This is it. So we also have noble clinicians in our lab. It means when the clinician has made his scannings, he sends the file into the lab, and we can see what his plans are, what his intention is to put the implants. And sometimes, we say, can you put the implant a little bit more to the palatal side or buccal side if possible? Here you can clearly see the scanning of an old prosthesis. And of course, when you have this, it’s very easy as periodontist or an oral surgeon to make your planning of the implants. Here can see this is the man we are talking about. He has seven implants in his upper jaw. And this was his old prosthesis. And a prosthodontist, he rebased or fine tuned a little bit the prosthesis, and he has worn this as a provisional. The midline was not OK. The horizontal plane was not OK. So we have to re-do a little bit the work in the correct way. So this is the road map for an edentulous patient. It means we start from zero. First of all, we do a set-up with acrylic teeth. Why do we do this? Because we want to have the right criteria before we start. It means the midline, the horizontal plane, the good occlusion. And when this is OK in the patient’s mouth, we take silicone indexes. And this silicone index is the reference for the rest of our technical steps in the dental laboratory. Once again– the cross-mounting. Again, this is the indexes, the buccal one, the incisal one. And then, of course, the preparation for scanning– we do this in resin because of the stability. You can do it in wax as well, but wax is more or less fragile. So we take pattern in resin. And here you can clearly see the scanning procedure. It’s a procedure. It’s very easily done. It’s, in fact, a scanner who does the work. We do the preparation, and the scanner does the work and delivers us a one to one copy of what has been scanned. So we have a consistent quality in the laboratory and for the clinicians and for the patients. When you have to cast those bulky restorations in metal, sometimes you have a good cast, and the next day you have a very bad cast. So consistent quality and precision are very important items also for the longevity of the implants and the longevity of the restorations in the patient’s mouth. So we go back now on the model, what we can see here. So we have to deal here with whether we have white or it can go into beige. But when you have to play with ceramics on top of it, it’s not so easy, especially when you don’t have a lot of space. Here, on your left-hand side, you can clearly see that we don’t have a lot of space for the pink porcelain, so we have to cover this. Once again, we close the articulator, and we have sufficient space for the veneering material. So we have a special powder here to cover a little. It’s not opaque material. It seems to be a little bit opaque, but it isn’t, so to have a better pink color of the ceramic gingiva. What we see here is the bisque bake, and here, we can judge, of course the lip support, the occlusion, horizontal plane, the midline. I was with the try-in in the practice, and I was not so satisfied. And this was a wonderful patient. He said, give me some teeth that nobody can see that we are dealing with false teeth. So you can see the discoloration of his lower teeth. This man was a smoker, and his intention was not to stop smoking. So this is then afterwards. So I stained a little bit to come closer to the lower jaw. This was the wish of the patient. You can see I duplicated the final restoration to see how the shape and the position of the teeth is. And you can clearly also see the texture, which is also very important. The texture is something that is from patient to patient. Young patients, they have more texture compared to elderly people. When you use gold power or silver powder, one can clearly see the texture of the restoration. So we try to copy a restoration as good as we can in all its little details. Here in the patient’s mouth, of course, this is the most important moment of our work. I mean our work– the work of the whole team, the periodontist or the oral surgeon, periodontist, prosthodontist, the dental lab. And of course, in the center of our efforts, is the patient. Now one can ask, why is the one incisor a little bit longer compared to the other one? OK, when you analyze the lower jaw, you can see that little bit twisted. And I think that they are more in harmony when we build up in this way. There is this facial harmony. When the patient smiles, no one can see. It was his wish that we have to deal with an implant-supported restoration. And this is the implant-supported restoration done, a total view of it, and I think it’s perfectly in harmony– the color, the discolorations, and the shape and position of crowns. So what are now the conclusions of this session or of this lecture? So the most important thing when we have to deal with implant restoration is a treatment planning. It’s very important. We have seen a few complex cases. And of course, when the situation is healthy, we can start. The occlusion is very important when we have to deal with zirconium dioxide restorations, the harmonious restoration– this is what we have seen the last case– and then the treatment team. Communication is so important. And then, of course, last but not least– the understanding of the dental technician of the beautiful material, zirconium dioxide. Thank you very much for your attention.