Running Time: 67 min
The Influence of Modern Clinical Strategies on the Integration and Reliability of the Prosthetic Outcome
Release Date: January 23, 2016Subtitle:
Hello to everyone. My name is Giacomo Fabbri, from Italy, and this lecture that I prepare for gIDE at [ the ] location is aiming to describe the influence of the [ motor ] clinical strategies on the integration and on the reliability of the prosthetic outcome. We will start speaking about the materials. In effect, today the condition have at disposal lots of materials that really has revolutionized the traditional prosthetic approaches. We can see that all the new material, new old and new metal-free material can be divided into two big family. The first one is the silica-based ceramics. These materials are characterized by main features, like the etchability, like the translucency, like the low flexural strength, and like the possibility to use the bonding technique with this approach, and so the possibility to cement this restoration with an adhesive approach. The other family is the high strength ceramics. High strength ceramics are characterized by a nice flexural strength, a high opacity, and no etchability. And they represent, really, two completely different worlds that must be treated, also, really different from the clinical and the technical point of view. To give you some examples, for example, the silica-based ceramics are really useful in cases of the treatment of the anterior segments. Like, for example in this case, when we treat the central incisor with the silica-based ceramics we’re creating a perfect integration, a perfect natural appearance, and obtaining a wonderful aesthetic outcome thanks to the translucency and thanks to, of course also, the ability of the dental technician. The silica-based ceramics are absolutely the best choice also for veneers, for example. We can see this case where we perform a multi-disciplinary approach with an orthodontic therapy– a minimal orthodontic therapy with Invisalign– that’s allowed me to move the teeth in the right position in order to minimize my preparation. These are the preparation of this case, where really I preserve lots of enamel to all the teeth that I prep. And these are the final outcome of that I achieved with these materials. Thanks to the high translucency, attaches to the possibility to etch this material. And it means that I don’t need retentive preparation on my element, thanks to the adhesion, thanks to the bonding approach. And here we can compare the result in the end of the treatment, and now we have result before our treatment. So the silica-based ceramics also are really useful when we want to work with really minimal thickness, like in this case where we treat the K9 with the veneer with a small thickness in order to manage this problem over an abrasion on the vestibular portion of the tooth, maintaining enamel as much as possible. And this is the result after the cementation, and after several years after the delivery. So these are the silica-based ceramics. What about the high strength ceramics High strength ceramics are really, really important to use when we need support– when we need the framework support for [ our oral ] [ addition. ] Like in this case, where we treat, for example, the anterial segment in the lower jaw with bridges from K9 to K9. And I love this image, because I want that you pay attention on the arrow. Look where I position my prosthetic margin. Really [ quarterly, ] really so far from the soft issues, and this represent really important advantages of this material. Because remember that many clinicians think that metal-free approaches are useful only for aesthetic reasons, but metal-free approach is a really useful because allow to us to preserve the tooth structure, and the same time it allow to me and to us to respect the soft tissues. Look at this case after 10 years of follow up, for example. We can see how the work is perfectly in function without any complications. And pay attention on the same recession that we observed before the treatment. We can see how we have the same recession. It means that we inspect the soft issues. If we place, for example, the prosthetic margin inside the [ sulcus ] or juxta-gingival, probably after 10 years we observe today as likely most recession, and more recession. So it’s really important to understand that the metal-free approach is something that allow to us to [ idolized ] aesthetics, but at the same time allow to us to preserve the tooth structure, and respect the biology– to respect the soft tissues. Look, for example, in this small video, the perfect integration of this bridge in anterior. We can see how the border between the natural root– between the crown is completing invisible, is completely [ mimetic. ] It’s impossible to see the difference between the natural root and my crown. I think that today it’s really crazy to think to prep a root in order to recreate an artificial root. We can absolutely maintain the prosthetic margin so far from the soft tissues. The high strength ceramics are really useful, also, when we have to treat dice chromic abutment. When we have, for example, a tooth that are treated by an orthodontic treatment, of course, and where we have an important discoloration. Because in this case it’s important to avoid to use really translucent material. Because with the really translucent material we can have the problem that the gray was transmitted through the copying, and so it can compromise the aesthetic outcome. Finally, the high strength ceramics are really important when we have to manage situations like this. So full rehabilitations, full arches, with big distal cantilever or big pontic areas. And of course, I think that the best option where we can use the high strength ceramics is the implant supported prosthesis, where we need the abutments– we need frameworks with their important strength in order to subordinate their rehabilitations. And this is possible not all in case of single crown, but in case, of course, of partial or in case of complete rehabilitations. Now, I want to stress this aspect– the aspect of the flexural strength. Because I’m sure that all of you– all of us– know perfectly that all the materials that the company shows us are classified by the flexural strength. Like if this aspect is the most important, and the only one to consider in order to select the right material for each clinical situation. But remember that the flexural strength is an evaluation made in the lab, where we’re taking a situation– the option to some feature with an evaluation that take [ prime ] [ newton ] on millimeter squared. So what does it mean It means that in relation to evaluate preferably the flexural strength, it’s really important also to understand the thickness of the material. So sometimes, using a stronger material in a minimal thickness, it doesn’t mean to have absolutely the strongest solution because, of course, the thickness that I can use with this material is absolutely important in order to evaluate the material to use. So, this flexural strength is absolutely really important. It’s really mandatory when we treat patient with this type of solution, like for large framework in case of implant, distal cantilever, big pontic areas in the posterior segments. But absolutely, the flexural strength is not so important when we have to treat the anterior segment. When we have to treat the single crown, for example. Because in this case, it’s important also to evaluate how I can manage the space for the restorations. And in fact, today, how I will show you after the topic– an important topic nowadays is the monolithic approach. The first experience with the metal-free material, in my opinion it was completely wrong, because we know how, in the past– 10 years ago– the companies tried to produce the copy with the smallest thickness. We start from 0.8 and arrived also to 0.25. And this approach means to use, of course, a layered materials– a layered approach. So we had the copy, and we add feldspathic porcelain to put on the top of the copy in order to recreate the aesthetics– in order to recreate, of course, the function. But this approach, in particular in the posterior segment, or in particular in all the clinical situation where we have an important risk– an important risk profile from a biomechanical point of view– like [ bruxism ], like bio-functional habit, a patient with bio-functional habits. This approach creates the risk of chipping, because remember that the feldspathic porcelain that we have on the top of the core is really brittle material. We speak simply about 100 megapascal, and in fact the chipping is a clinical reality that happens in all clinical practice. And the problem– what is the problem The problem is that in the past, typically we used really thing thickness of the copying, and we put on the top of this thickness one kilo of feldspathic porcelain. Look at this case, for example, and look which thickness we use for the copy. OK, we can use also the zirconia, of course, that is really a strong material. But if we use this material with a thickness of 0.3, is not correct– is not the right thing to do. Because with this minimal thickness, of course, my restoration, my crown cannot be so strong– cannot withstand two important forces in occlusion and during the bite. Look this case, for example. Another [ my ] complication after six years, and we can see how I observe an important fracture, but look how I manage the thickness. 0.4 for the core 1.4 millimeter for the feldspathic porcelain. This is the reason why I observe this fracture. This is the reason why today is to really fashion– to speak about monolithic approach. Because in this way, we avoid to have the combination between two materials and we have only one, single material. There right material, the best material to use with a monolithic approach, should have particular features. First of all the translucence, because it’s the only way to achieve a good aesthetic, simply with the color or a painting approach. The third aspect is the strength, because it’s important to have a correct strength of the material in order to avoid to have important fracture, or to have bio-mechanical complication. And in the end, the third aspect is the etchability. And really, I’m really a fan of this aspect because it allow to us to be really minimal invisible on our patients. So the two options that today we have are the monolithic lithium silicate that we can work with press technology or cadcam technology, and the second option is the zirconia that also today can be used with the monolithic approach. So now we are going deeper to each element. What about the translucency We know how the lithium disilicate is a silica-based ceramic, and so absolutely it has a superior translucency. Even if today, also the zirconia– thanks to a new modification application on this product– also the zirconia really can have a good translucency, but not comparable to the translucency of lithium disilicate. Look at this case, for example. The same patient– in this case I realized two works, two bridges. One in monolithic lithium disilicate, and the second one monolithic zirconia. And I want to show you, for example, the difference between the two materials, and we can see clearly here how the lithium disilicate is absolutely more translucent respect the zirconia that is too opaque. And also, if we see the result in the mouth during a [ training ] we can see how the natural appearance of the lithium disilicate is absolutely better than the natural appearance of the zirconia. And remember that today we have high translucency zirconia like these that are shown in this slide, but remember that this type of zirconia has a flexural strength of about 600 or 700 megapascal, not 1,200 like the traditional zirconia that we use, for example, for abutment or for the framework. So remember that, yes, we have a better result in terms of aesthetics, but we go to compromise this flexural strength. And remember that lithium disilicate has 400 megapascal, and this type of zirconia has 650 megapascal. So there is a difference, but it’s not too much, like in the past where we have 400 versus 1,200. So what about the strength The strength is really important. Look at this complication. This is a monolithic crown in empress one with 200 megapascal, and is not so reliable because the flexural strength is not enough. And we know how the flexural strength of lithium disilicate ranged 380 and 420, while the flexural strength of zirconia ranged from 650 and 1,200 in relation to the material that I select and in relation to the translucency that they want. Because remember that with the 1,200 zirconia, of course I have more opacity respect the 600 and 500 zirconia, of course. And what about the etchability This is, for me, really the most important aspect to consider when I select a material in my clinical rehabilitations. Of course, for the lithium disilicate it works, because it’s an etchable material, while in the case of zirconia it doesn’t work, because it’s impossible to etch the zirconia. And so with the zirconia, the adhesion– the bonding– is not reliable, like in case of silica-based [ ranks. ] And what does it mean It means that with lithium disilicate I can use the bonding and can do minimal invasive preparations without a real retentive preparation, like crown for example. But they can produce also veneers, tabletop, in-lay, on-lay, while with zirconia I’m forced to use this material simply for crowns or bridges. And, in my opinion today that I love to work on enamel, the idea to prep all teeth like a crown is something that doesn’t make sense. This is the reason why, in my opinion, the lithium disilicate, like all the etchable materials, are absolutely the go to solution in terms of modern restorative dentistry. The enamel. The enamel is something [ that’s ] really important in order to preserve our teeth, in order to achieve predictable, reliable restorations. I want to show you this case. Look here, an old case. Look these two metal crown with 45 years of follow up, and look what I observe when I remove this crown. I observe untouched teeth. No cavities, nor any type of problem. Why For the material For the cement No, simply because the colleague in the past preserved the enamel, because enamel is really important in order to preserve the integrity of the tooth, and in order also to protect the tooth from the biological complication like the [ carrier, ] for example. So the first target, the first thing to respect when we prep a tooth is to preserve the enamel. And if we preserve the enamel, the second aspect is of course to use adhesion– to use the bonding– because we have the possibility to create a perfect gel, a perfect combination between the enamel and the restorations. Restoration that, of course, it must be a product by an etched porcelain, like silica-based ceramics. In this way, I etch the enamel, I etch the material, and I can obtain a perfect combination between the two components, and I can achieve a reliable solution and reliable restorations. I want to show you really a crazy case, just to demonstrate to you how really we have to believe in adhesion. Look at this patient. A really young patient with the problem of cross bite on the K9– or the lateral K9. She asked me to treat this case for many years, but I refuse this treatment because the ideal solution, of course, is the orthodontic therapy. But she refused orthodontic therapy. And I don’t remember exactly when, in terms of years, back at one time I decide to treat this patient in order to satisfy, completely, her requests. And so which is my treatment plan, in order to be minimally [ invasive, ] in order to respect the tissues– the soft tissue and also the tooth, also the hard tissues. My idea was to do something thanks to the adhesion. Look here, first of all we have case of altered passive eruption. So it means that we have to remove these soft tissues, these gingival on the K9 because we have enamel that is under the soft tissues. Should I plan also a periodontal therapy, a periodontal surgery. But first of all, like in all my treatment, from the limited treatment to the really extensive rehabilitation I do the mock up. Because the mock up is something [ of ] priceless value, because allow to me to give to the patient the opportunity to see the final result before to start with the treatment. And in this case, of course, I’m sure that the result– that it works for the patient. But my topic, it was to evaluate how the patient feels with this tooth in the mouth that is really big. Because before to do definitive result– definitive restorations– in this case, really, I want to check if the patient really is good with this solution. And of course, she felt good. And so I decided to start with my treatment. And so periodontal surgery in order to expose the enamel, and after the complete healing we decide to do the restorative treatment. And which kind of restorative treatment Look here, I decide to do really minimal [ invasive ] preparation, a partial preparation of the buckle aspect just to create an area where to cement my veneer. Look here, the preparation. We can from the white line how I maintain my margin on the top, respect the inferior lower teeth. We can see also in these image how is the preparation, and we can see how the inches a portion of the tooth is completely attached– is completely preserved. And this is my restoration in lithium disilicate. This is the cementation using the rubber dam. Really important in order to control perfectly the cementation, the excess of cement, to control the feet of the restoration and also the feet of the margin on the tooth, in order to be able to be sure about the integrity of restoration and to avoid to have infiltration in the future, of course. And this is the situation before the treatment. This is the restorations, looking at which important thickness, and this is the outcome. So it’s a crazy case, a really small one, but just to give you an idea that with adhesion, really, we can work. And after seven years the restoration is still in the mouth, perfectly in function, without any type of complication or without any sign of potential complication. And so, of course, the adhesion is absolutely reliable. And absolutely we have to work with it in order to idealize our treatment and preserve the structure of the tooth that we are going to treat. So the topic is that we work with the veneers from 20 years, and from the clinical data we know that veneers are a reliable solution, because we know how, after 20 years of follow up, we have a survival rate of 83% percent, and it’s absolutely a good value. So the idea is that we have to try to transfer the approach of the veneer to the crown. So we have to transfer the approach from veneer to crown, because today it’s possible. It’s possible because we have the possibility to work with restorations with really a minimal thickness, and it allows to us to preserve enamel on the buckle portion of the tooth, on the palatal portion, and we’re not also in the interproximal portion. I want to show you this case, for example. I love this slide because in these slide we have two [ hipoc, ] two times of the restorative dentistry. On the first molar we have a monolithic lithium disilicate crown. On the second molar we have a fused gold crown. This two restorations are really distant in terms of years, in terms of times, but are really similar in terms of concept. Because they maintain enamel, and they take into consideration only one material, a monolithic approach. This patient had a gold crown also in the first molar that I removed for biological complication, and so I decided to treat these patient with this new normative approach. Because this is what I found when I removed old crown. And look, it’s an untouched tooth with a good portion of enamel. A vital tool, of course. And so why I have to prep a lot Why I have to prep again this element My approach was simply to refine the preparation in order to define perfectly a margin, a slight margin, and I produced a monolithic restoration lithium disilicate with the same thickness of the gold– the same thickness of the gold. So, 0.6 millimeter on the axial [ wall ], and 1 millimeter, or one millimeter and two, [ occulsaly ]. And I cement the crown with an adhesive approach, obtaining this type of result. And my follow up is five years– simply five years– while the other the result, the other crown– the gold crown– had a follow up that is [ superior ] to 13 years. But I preserve the vitality of the tooth, I reserved the enamel, and so I’m able really to treat perfectly with a minimally invasive approach this kind of tooth. Thanks to the new material, and thanks to a right selection of the material in relation to the case that I have to confront. So I want to show you, also, this evaluation. This is my treatment. One 2004, the second one in 2008, and the last one in 2012. And I want to show you really quickly how the management of these kinds of patients is changing during these years. Look, for example, here– the preparation in the upper jaw– in 2014, in ’08, and ’12. And look today we are really minimally invasive respect to 2004 and also respect to 2008. Because today, we know how it’s possible to reduce a lot the invasivity of our preparation. And also, concerning the selection of the restorative material, it’s completely different. Because in 2004 I used layered lithium disilicate in the anterior, layered zirconia in the posterior– a big mistake. In 2008 I used a layered approach anteriorly and a monolithic approach posteriorly, with this thickness. So posteriorly I maintain 1.5 millimeter in occlusion, and anteriorly I maintain 1.2 millimeters. In the last case in 2012, the situation changes again, because I maintain a posterior monolithic approach with minor thickness. Minor thickness, because if I have enamel I can also work with the restoration with a thickness of 0.5, 0.6 millimeter in occlusion. It works if I have enamel, and if I perform their right cementation with the correct adhesive approach, with the adhesion, of course. While in the anterior segment, always a layered approach– in particular, when we have a patient with an important expectation– but with minimal thickness. We can see how the thickness is 0.8 millimeter. So really, during these years we can see how we changed the materials. We changed, also, how to use these materials, and we changed, also, how we prep the natural dentition– how we prep the teeth. And really, we are in the [ hipoc ] of the minimal invasive approaches in order to respect the soft tissues, to respect the teeth, maintaining the enamel, obtaining really reliable, reliable solutions. The idea to use monolithic approach with silica-based ceramics started with [ Petroguess ] from this in vitro study where she assessed how monolithic lithium disilicate crown in full volume, in a full contour, [ resist ] until 900 newton without any fraction. While in the case of layered and layered zirconia crown– so treated with feldspathic procelain– simply after 200 newton they manifested fracture. Why Simply because I know that zironica is the strongest– is stronger than the lithium disilicate. It’s the strongest solution that we can use. But I have to put on the top feldspathic porcelain this is really brittle. It’s brittle in terms of material, but it’s brittle also in terms of combination that we can obtain from the material and from the feldspathic and the zirconia. So, with the framework. I want to show you this case. A young patient that asked me an aesthetic treatment. And look at the x-ray, the situation of the mouth is perfect. It’s really in excellent condition. The majority of the teeth maintain the vitality. We have two teeth with endodontic treatment. But anyway, if I want to treat this patient with an aesthetic treatment, it’s important for me to take into consideration that it’s a young patient. So I have to create a reliable solution in order to don’t compromise the integrity of the teeth, and to give to the patient, really, a predictable result with a good endurance in time. This is the [ interoral ] situation, and we can see how we have problem with the length of the teeth, with the proportion, and of course we have to create– we have to plan a multidisciplinary approach in order to create the space for my new restorations. In fact, we can see how, in this case, we plan to change the proportion– to change the length– do 2 millimeters apically, 2 millimeters and 0.5 incisorly in order to create the right proportion. And of course, in this case it’s mandatory to perform a mock up, and it’s mandatory, of course, to perform a multi-disciplinary approach in order to move all teeth in the buckle direction, in order to create [ justima, ] and to have, finally, this space for our restorations. This is the image– this is the pic after this orthodontic therapy after, more or less, one year. So now, I can continue my treatment with, of course, the periodontal surgery in order to expose the enamel that I have under the soft tissues because also in this case where we have an altered passive eruption. And this is the phase of the surgery where we go to design the new profile of the soft tissues. We can see in dark line the old position of the soft tissues, and we can see in the white line, exactly the position of the cement [ animal ] junction. So where I will replace the soft tissues after my surgery. And this is the result after the surgery. So now, I’m ready for the prosthetic therapy. And so in this case I have to [ idealize ] the occlusion, I have to [ idealize ] the aesthetics, and so the only treatment that we had planned, it was to preform a full mouth rehabilitation in the upper and the lower jaw. And in these case, when we work on at least one arch, it’s really important always to take into consideration the option to increase the vertical dimension. Because if we increase the vertical dimension, we have the possibility to create the space for our restoration, and so we have the possibility to reduce the impassivity of our restorations or our preparation. In fact, I know– in my experience, I realized that when I would treat, for example, both the arches– both the jaws– if we increase the vertical dimension of 4 millimeters anteriorly, we have the possibility to create a space on the second molar of 2 millimeters. It means that, in this case, we have one millimeter material for the restoration in the upper jaw, and one millimeter for the restoration in the lower jaw. Of course, we know that when we have to increase the vertical dimension, it’s important before to evaluate several aspects in terms of TMJ, muscles– but anyway, it’s an option that is absolutely useful in this case, in order to obtain a perfect minimal invasive approaches and to respect the structure of the teeth. So I want to show you the preparation of this case. Look here, these are the preparation that I perform. And in all this case, always I don’t do the anesthesia, because it doesn’t matter. Because I don’t arrive in dentine. I don’t touch the dentine, because my preparation is limited in enamel. And I want to show you the– in want to compare the upper jaw after and before the preparation. It’s really similar. We can see, OK, the cord inside the sulcus. But stop, we [ open ] likely the interproximal area, but we can see how we don’t touch, for example, the palatal aspect of the anterior teeth. We maintain the enamel. We maintain the enamel also on the buckle aspect. And so to maintain the enamel it means to preserve the integrity of the teeth. This is the final restorations by Gioncarlo Barducci, and of course the posterior monolithic approach, in order to beef up our restoration posteriorly. In order to reduce the invasivity of the preparation, and in order to have the reliable solution as much as possible. About the cementation, I’m a fan of adhesion, and so I like to use the rubber dam in order to control perfectly the feet over each crown, of each veneers, or each bridges. And in this way, I can really refine perfectly the margin. I can check exactly if I remove completely the excess of cement. And so it’s a good thing for the patient. In particular, it’s a good thing also for these soft tissues, because in this way it is impossible to have excessive cement that can irritate the soft tissues. Someone think that it’s really difficult to put the rubber dam in [ process ]. It’s difficult if we prep the teeth we a really deep preparation inside the sulcus. But if we maintain our preparation juxta-gingival– or why not, also extra-gingival, because we have any reason to place the prosthetic margin, for example, intra-gingival on the palatal aspect or on the lingual aspect No, in fact today, really often, we do tabletop that stay really distant from the soft tissues. In particular, in the lingual and the palatal aspects. And look here, in the high magnification, at how really we can control perfectly the matching– the gel between the restorations and the teeth, the root. So these are the restorations on the model, and this is the result that I achieved after the cementation in the upper and in the lower jaw. And look here, also, which kind of material. Monolithic, lithium disilicate posteriorly and layered anteriorly. Because this a young patient with high expectation, from an aesthetic point of view. This is the frontal evaluation of the upper, and here we have the evaluation in the lower. This is, for example, the [ face ] of the [ train ], where we control, for example, the color, where we control the occlusion. And then here we have the final result after the cementation of the lower restorations. Important, also, the function. So anterior and lateral guidance. And we can see here how we preserve– from the x-ray evaluation we can see how we preserve, perfectly, the vitality of all the teeth, because we maintained enamel. We don’t do anesthesia with the preparation. This is the aesthetic integration in the face of the patient. So really, we are able to manage, perfectly, this complex tissue situation, where we had, also, a gummy smile. So we are able to reduce the gummy smile to change the aesthetics of this patient, maintaining the integrity of all the teeth, and so, obtaining, absolutely, a reliable solution. Remember the case that I show before, with 45 years of follow up, of metal crown cemented with a normal cement, back that after 45 years they allowed me to get a perfect intact teeth, thanks to the enamel. So this is the baseline, this is the result after one year, and this is the result after two years. And here we have the evaluation also in an x-ray before and after the treatment. Actually, in the last year– in the last two years or three years– usually when I treat patient we deny risk of fracture, of chipping– biomechanical complication– due to, for example, the muscle. Like, for example, [ brachiofisopation ], or due to, for example, para-functional habits, like bruxism or like clenching patient. Also, due to the occlusion. Because remember that the occlusion is like the contest– it’s like the [ place ] where our restoration must be survived for many, many years. So if the occlusion is good– is perfect– probably the restoration can work many, many years. Is the occlusion is not perfect, our restoration will be more stressed during the function. So in all these clinical situations, I think that the idea to beef up our rehabilitation is a really good point– it’s really the go to solution. And this is the reason why today, in many clinical situations, I use a monolithic approach also anteriorly, in order to avoid, absolutely, the risk of chipping. Because today, with the right technique and with a good experience, it’s possible really obtain good result also with the monolithic approach in aesthetic area. For example, this kind of preparation, really minimal invasive, and these are four crowns in monolithic lithium disilicate, with a follow up after five years. Absolutely, the result– it works. It’s not an excellent result, but absolutely it is a good result that is enough to satisfy the expectation of the patient. And as always, I like to do like this– to cement my restoration on enamel. You can see how, in this case, I have enamel also in the margin. So completely, my restoration is bonded on enamel. And here we have evaluation during the smiling and intraorally– completely monolithic. Another case, for example. A bad occlusion. Patient that breaks, continuously, the incisal margin. This is the occlusion. We don’t have contact with anterior segment. So I decided to do a crown, but without a preparation on the palatal aspect because I have just the space for the crown, thanks to the open bite that I have anteriorly because the teeth– the upper and the lower teeth– aren’t in touch– doesn’t touch. And this is the preparation in the buckle aspect, maintaining the enamel. This is the preparation in the palatal aspect, and we can see how I design at the margin, and stop– that’s it. I removed the undercuts and I maintain, of course, the enamel. Look here the thickness that I use. In some area the restorations had a thickness of 0.2 millmeters– really thin. And look also in these case, the cementation with rubber dam maintaining enamel, and with the prosthetic margin on enamel. The best option that we can achieve during restorative dentistry. And this is the final outcome simply with the monolithic approach. Another case of monolithic approach similar to the case that I have just shown you. Minimal invasive preparations in the vestibular portion, and also in this case this is the result after cementation, and after five years of follow up. So I think that, in this way, it’s possible, really, to idealize our rehabilitation. In particular, from a functional and from the point of view of the reliability. I think that for many clinical situation it represents, really, the main target to get. I want to show you another case. A complex rehabilitation with a bad occlusion parafunctional habit. We can see, in fact, the important deep bite that we have. We can see, also, the situation on the lower teeth with important abrasion, erosion. We don’t have too much enamel, but in a way we can proceed with the same approach. Look here, the occlusial evaluation in the upper and in the lower. We can see the important erosion in the upper jaw. In particular, on the anterior teeth, from premolar to the central incisors. And the approach, it was the same. Increase the vertical dimension, and to rehabilitate both the arches– both the arches. And this is the preparation. Look here, minimally invasive. Of course, without anesthesia also in this case. And this is the result before and after the treatment, trying to idealize the occlusion and, of course, also the aesthetics. But remember, with an important strength in occlusion. So the main topic here is to have, really, a reliable, a strong rehabilitation. The other side. The function, anterior guidance. I want to compare now the lower jaw before and after the preparation, and we can see how, really, it’s minimal invasive. And this is the final outcome after the cementation. The same thick in the upper, before and after the preparation, and this is after the cementation. And this is my result after my treatment with the monolithic approach. In this case, monolithic anteriorly and posteriorly lithium disilicate. In this way, I’m sure that for this patient I used the best solution that I could. Another case. This patient came to my care because she want to treat, simply, the lower teeth because she didn’t like the appearance that are really were, and so she asked me my idea, my treatment. Look here, we have an important extrusion of the lower teeth thanks to the erosion, thanks to the abrasion. And this patient stayed also to another colleague, and the colleague proposed to do endo on these anterior teeth with the periodontal surgery in order to recreate a perfect to aesthetics, a perfect appearance. But it’s not the right solution. First of all because, in my opinion, if we endo this [ treat– ] so we treat this element with an endodontic therapy– and then we do periodontal surgery with the epical reposition of [ flat, ] it means, in my opinion, that this element, probably in the next year– and who know if after three, four, five, or eight years– but probably will fail because I really compromised it. And secondly, about occlusion, a really not an ideal situation. Because we have also in this case a deep bite, we have a cross bite posteriorly. And theoretically, in this case the best option would be to treat both the arches. But the patient was really rigid, and she want to treat simply the lower jaw, because she did the full crown in the upper just three years ago. So my treatment, my idea was to do restorative, of course, but not in this way. So not to obtain the space for the restorations epically with the periodontal surgery and with the endodontic treatment. My approach, it was a restorative thinking to move the teeth in the cardinal position. Because remember that the patient request was to treat the anterior for aesthetic reason. And for aesthetic reason, these teeth required to move the incisal edge cardinally, in order to have a good exposure of these teeth at rest, and doing the smiling, and during the phonetics. And so, to do this approach it’s mandatory to proceed with an increase of the vertical dimension. The same thing that we did in the first case. In this case, it’s simply one arch, and so I increased 2 millimeters anteriorly from K9 to K9, and automatically I have 1 millimeter in the posterior segments. The increase of the vertical dimension in all these cases where we have also a minimal over jet, it’s something really important, because allow to me not only to obtain the space for the restorations posteriorly, but also allow to me to increase the over jet, and such to idealize the anterior and lateral guidance. Because we know that the first movement is basically a rotation, and so it means that if we open– if we increase the vertical dimension, automatically we move the incisal edge, the buckle surface of the lower teeth in the back direction and in the epical direction. So move down and back. And this is really important to idealize the occlusion, and also the function. OK, so also in this case we increase the vertical dimension of two millimeters anteriorly from K9 to K9, and automatically in this way we obtain the space for the restoration in the anterior segment. Because remember that 2 millimeters anteriorly, it means 1 millimeter posteriorly. This is something that I observe in the 95% percent of my rehabilitations. So this is the wax up that the dental technician produced thanks to my indication that always I give to the lab in order to produce the perfect the wax up. And now, I want to show you another thing that, for me, is really mandatory in our prosthetic approach. That is, the mock up. Look at this video, for example. We can see how always, in this clinical situation where I perform an increase of a vertical dimension, always I do the mock up, because the wax up is in addition. And so I can create the volume of the wax up– I can create the volume of what the dental technician did in the lab in the mouth of the patient. And in this way, I have the possibility to test the aesthetics but also the function. So we use these trays– this transparent tray and this transparency silicone using to stamp the new volume in the mouth. The reason the we use the Luxatemp is it’s really an excellent material for this approach, because we can use it in several color, and so it’s possible to obtain, also, good aesthetics. In this case, for example, I performed the approach in three different steps. First of all the anterior and then the posterior segment. This is a normal video that I do during my practice in my office, so it’s normal sometimes to find some bubbles. But it doesn’t matter, because with some flow composite we can really correct– we can manage this defect in order to create the new anatomy, the new shape. And it’s really important after this kind of work to be sure that the patient is able to use the micro brush in interproximal area in order to maintain their oral hygiene, because I love to leave this mock up in the mouth of the patient for at least one month. Because in this way, when in the mouth we can test not only the aesthetics, but we can test the phonetics, we can test the function, We can test the vertical dimension, we can test to don’t have any type of problem at the TMJ or at the muscles. Really important thing to do. So, this is the result after the second steps, and this is the result after the third one. So now I have exactly the wax up in the mouth of the patient, and so I can test everything. How you have seen, in this case, when you want to maintain the wax up in the mouth for a period superior to one month, it’s important to etch the surface of the enamel in order to create a perfect bonding between the composite and between the surface. And this is the result of the mock up after 40 days. So the patient has tested, perfectly, the new occlusion, the new situations. And now I can start with my treatment with the preparation of the teeth. And look how I prep the teeth. Really minimally invasive. I maintain the enamel. The occlusal portion is attached because I obtain the space for the restoration simply thanks to the increase of the vertical dimension. Look at the evaluation on the occlusal aspect. In the mesial aspect on the second premolar, I remove probably a carrier. I don’t remember exactly on the reason why I create this important hole, but we can see how the occlusal surface is absolutely attached. And remember that the cementation is an adhesive cementation, so if we have the possibility to use a rubber band, it’s absolutely the best option– the best solution. In this case, we produce veneers, crown, tabletop, and this is the result after cementation. A monolithic restoration. So I know that if I use a layered approach, I can obtain and better result. I know. But in this case, I want a good result from an aesthetic point of view, but particularly I want, really, a reliable solution. I want a strong solution for my patient that he has a bad occlusion, not ideal occlusion, and in the same time he has, also, parafunctional habit. And in fact, always to my patient that I treat with this approach, I deliver also a night guard– an appliance to wear during the night in order to preserve the restoration. And here, we can see the result before and after the treatment. Look here, location of the prosthetic margin is absolutely extra-gingival. But we can see how it’s really difficult to find it, because the blending between the surface of the root, the surface of the tooth, as the surface of my restoration is really perfect. This is the occlusal evaluation, and we can see how in this area that I marked with the circle, I produced tabletop. And we can see how the marginal is really cardinal– is not a crown, is not an overlay. And I know how to call it, because it’s a restoration that works in the occlusal portion and the vestibular portion. And this is the x-ray evaluation, just to see how I maintain, perfectly, the vitality of all the teeth, maintaining the integrity from the structural point of view, and so with maintaining and obtaining, of course, a good reliability. And this is this outcome before– this is the pics before and after the treatment, and we can see how also with a simple, monolithic approach we can obtain a good integration of our restorations. All these my experience– I have collected all my experience with this approach, and I have published this article in 2014. This article takes into consideration 860 restorations in lithium disilicate placed in the anterior and the posterior segment with this approach. So with a minimally invasive approach, with minimal thickness. And 32% over the patients that I treat were patients with severe parafunctional habits. And my result was that success rate– not the survival, but the success rate ranged 95% to 100%. With patient that the 33% has severe parafunctional habits. So it’s absolutely a good result. These are absolutely reliable solution to use when we have the possibility to maintain the enamel, and whenever the possibility to restore– to manage their rehabilitation with a single crown. What about bridges What about bridges In particular, what about in anterior bridges So today, when we have to treat bridges in the anterior, it’s normal that we have to assess several parameters. Like, the span of bridge– how much is it– the aesthetic demands of the patient, and of course the biomechanical risk of the patient. Remember, the muscle, the bruxism, the parafunctional habits. And in relation to these aspects, we can select these types of solution. Now I want to show you a solution with monolithic lithium disilicate versus a solution in monolithic zirconia, just to show you the difference in terms of translucency. In terms of, of course, translucency, remember that this zirconia that I show you is the zirconia with the highest translucency that today we have at disposal in the market. An HD zirconia from Japan. And look, also, the difference in weight. The zirconia is a really dense material. This is the reason why the weight is like double of the lithium disilicate, 1 gram versus 2.3. And this is the result with the lithium and the zirconia. The natural appearance is absolutely superior in the case of lithium disilicate. What about the posterior bridges We have to do the same evaluation, the same considerations, so we have to assess the span of bridge, the aesthetic demands, and the biomechanical risk for the patient. And in the case of posterior, we have more options. But honestly, I think that the best ones are these ones that I marked with a green V. Remember that when we work with the layered zirconia, we know how really often we can have the problem with the chipping of the porcelain on the top. Because remember that I spoke in the first part of the lecture– the feldspathic porcelain is really brittle. And really often, also, the bonding between the ceramics and the framework is not so reliable. And so this is the reason why we can have cohesive or adhesive chipping. Look at this article. 10 years follow up with the zirconia restorations. Specifically, with the unlayered zirconia restoration. And we can see how the incidents of chipping is at 32%. And also it’s really important to assess how the chipping is more present in cases of bridges with more than four or five units bridged. So absolutely, if we use the monolithic approach anteriorly, why not to use monolithic approaches posteriorly in case of bridges Because it’s absolutely something that can work from aesthetical and functional point of view. The easiest option is the monolithic zirconia, because today we can manage the translucency of the zirconia obtaining a satisfactory result. This is, for example, a bridge in the posterior, in the upper jaw, simply colored, without any layered material. This is a bridge of zirconia of 650 megapascal, and here we can see exactly the translucency that we can achieve. Remember that monolithic zirconia is something that today is yet experimental, because we don’t have important clinical data about this solution. We know how the anatomic [ court ] of zirconia produce less antagonists to wear than the feldspathic veneers– porcelain. The important thing is that this zirconia must be really polished, and the best way to polish the zirconia is using the mechanical instruments. But the topic is that from in vitro study we know that after the evaluation in vitro, all the restoration in the antagonist dentition with enamel showed crack after this evaluation. What does it mean It means that if we have a monolithic zirconia, and as antagonist we have a natural dentition, from this in vitro study, this in vitro study showed how old the antagonist that was opposite to monolithic zirconia manifest crack. And so it means it depends on, absolutely, the rigidity of the zirconia that is really, really high. And it is an element that we have to consider in our clinical practice, in order to select the right material. But remember, that is an in vitro study, add about the clinical relevance of these aspects it’s impossible to have some imperfect evaluation. So we don’t have a clinical relevance. We have simply a data from the lab. So it means that it is not something that is absolutely real. Other option could be the combination between zirconia and monolithic lithium disilicate. Like in this case, where I have a patient with a high expectation from an aesthetic point of view, even if we speak about the posterior segment. In these case, we use the framework in zirconia to give a good support to the bridge, and then we produce a second framework in monolithic lithium disilicate to cement on the framework on zirconia. So to cement on the first framework in order to create recreate the occlusion and to recreate the normal shape, the function of these bridges. And in this case, we have [ 1,200 ] megapascal like framework material– for the framework material– and we have 400 megapascal for the lithium disilicate, and so we have a strength in occlusion of 400 megapascal. The combination between the two materials can work with an adhesive combination, so with an adhesive cement, and we can see here the restoration after the pairing approach, after the combination between them. Zirconia inside, and lithium disilicate in superficial. And here we can see the border between the zirconia and the lithium disilicate. And absolutely, the match between these two materials is perfect. This is– for an example, this is what we can achieve with this kind of result. On the second molar, I want the prosthetic margin juxta-gingival because from an aesthetic point of view, in this area it doesn’t matter. But I want to check, perfectly, the feet of my bridge. And other option is the combination between zirconia lithium disilicate, but lithium disilicate obtaining by the cadcam technology. So it’s made a silicate that is combined with the zirconia thanks to a crystallization process in the [ oven ], and it is weighed. Thanks to a ceramics called crystal connect it’s possible to combine perfectly these two materials. Another option could be to combine the monolithic lithium disilicate to metal framework, because sometimes– really rare situation, fortunately– we don’t have the possibility to produce a zirconia framework. Like in this case, where we have abutment on the implant– old implant that the patient had– and this abutment had a really sharp design. So with a sharp design it’s better to don’t use– it’s better to avoid to use zirconia. And if I go to prep again this abutment, I have the risk to reduce the vertical height, and so don’t have enough retention for my bridge. So in this case, I produce the restoration in this way. Metal framework, and then monolithic lithium disilicate cemented on the top, thanks to the adhesion– thanks to adhesive cementation. So an adhesive combination, of course, also in this case. Metal and monolithic lithium disilicate, press of course. I use 99% press lithium disilicate, because it’s more easy to manage, it’s more precise. We can obtain better anatomic surface, better design respect the cadcam one. And this is the result of my treatment. This is a before, of course, and this is after my treatment. And here we have an x-ray evaluation of this case. So in this, my lecture, I wanted to expose– I wanted to introduce this topic. It’s really an important topic that it could need days to speak about this topic– speaking about crowns, bridges, and all kinds of rehabilitations. But remember that our topic must be the integration from an aesthetics, and functional, and biological point of view, remember that I have a motto. And my motto is, first of all, respect the biology, thinking minimally invasive and working with adhesion. In this way, really, we can have the possibility to preserve the structure of the teeth, to respect the biology, to respect the soft tissues, and obtain prosthetic outcome with good aesthetics– with excellent aesthetics and excellent function and, in particular, with a good reliability. Thank you for your kind attention.