Running Time: 43 min
The use of zirconia is an esthetic alternative to metal for implant supported frameworks and it is considered primarily for its high biocompatibility, low bacterial surface adhesion, high flexural strength, and high mechanical features due to the transformation toughening mechanism. The zirconia frameworks in fixed prosthetic restorations supported by implants is commonly covered with hand-layered overlay porcelain. This technical procedure is highly esthetic but it causes some complications such as fracture of the porcelain layers. The purpose of this lecture is to introduce an innovative approach for creating an esthetic fixed ceramic implant restoration to minimize and facilitate the repairing of these mechanical complications. This approach provides the combination of zirconia frameworks with lithium disilicate restorations cemented on the top with an adhesive cement in order to have final screw retained rehabilitations. This technique can be used both in cases of partial or complete rehabilitation and the topics that we will discuss are concerning the framework design that is a prosthetic design not anatomical design like in the case of a layered framework where it is important to maintain a uniform thickness of layered ceramic on the top. The manufacturing of monolithic lithium disilicate restorations both anteriorly and posteriorly, lithium disilicate is a material that doesn
Release Date: November 11, 2014Subtitle:
Hello to everyone. I am Dr. Giacomo Fabbri from Italy. And in this lecture that I prepared for guided notation is aiming to describe an innovative prosthetic approach on implant support rehabilitations. This technique is finalized to reduce the incidence of chip or fracture, and at the same time to simplify the management of biomechanical complication. This approach is based on the ideas of combination of zirconia framework with monolithic lithium disilicate restoration. We start speaking about zirconia. Zirconia is the material that has really revolutionized the traditional prosthetic approaches in the last 10 years. In fact, we can take advantage from these material from several points of view, like in biocompatability, low plaque adhesion, flexural strengths, and esthetics. In this case, for example, we can see critical clinical situations, when we have continuous teeth on the right side, and adjacent implants on the left side. So we know this is one of the most critical situations that we can have in our clinical practice. But anyway, with this zirconia abutment it’s possible to contain a perfect soft tissues integration. And in fact, it’s really difficult to find difference between the soft tissues integrations around the teeth and the around implants. And it’s very difficult to find difference from half point of view, color point of view, and also textural point of view. With these option we can really analyze the soft tissues integration, and at the same time we can also simplify subclinical procedure. Like for example, the cementation where we know how it represents really critical a aspect. Because in particular, in implant support rehabilitation it’s really important to be sure to remove completely the excessive cement. And if we have a prosthetic margin more coronally, like a juxagingival or extra gingival, it’s possible to be sure to remove perfected or the excessive cement. I want to show you the finalization of this case after one year from the delivery. We can see the perfect soft tissues integration, good dental composition. And also, after seven years, we can see how we have a stable result. Probably we have a slight recession on the implants, on the buccal aspects. But it doesn’t represent any type of complication. Because with the white color of the zirconia, it’s impossible to compromise the esthetic outcome. From the clinical data point of view, we know how today we don’t have a long-term clinical study. We know how at five years the success rate of the zirconia abutment and titanium abutment can be considered similar. And in the same time, from in vitro study, we know how it’s really important to consider the type of the connection. Because in case of the zirconia abutment, we can have zirconia abutment in the internal connection with metal component. We can have external connection. Or we can have internal connection in the full zirconia. And from this point of view, the last option– so the full zirconia, internal connection abutment– are absolutely the weakest, from the biomechanical point of view. I want to show you, this is my experience– that has not been published, but probably it will be published in the next year– where I assess 541 zirconia abutments. And I analyze the survival rate in relation to the type of the connection. And I placed 233 zirconia abutments with internal connection and metal components, 198 external connections zirconia abutment, and 110 zirconia abutments with internal connection and full zirconia. And I observed this fracture– zero in the case of internal abutment with metal component, one for external connection, and six in the case of full zirconia connection. And it means that these results are absolutely linear. It’s clear like the in vitro study that we have. Because in the case of full zirconia connection, the critical aspect is about the thickness of the internal walls inside the implants. And so it means that in case of a critical situation, from a biomechanical point of view– like patient with a severe parafunctional habit, or like periodontal patient– it’s better to choose for an implant with internal connection and metal component, in order to avoid complication with the abutment, with the stability of that abutment. The second option that we can have with zirconia and implant support or rehabilitation, it’s about the framework, the zirconia framework. To treat full arch or partial for rehabilitation. And from the clinical we know how it’s really difficult to find the fracture of the framework. The problem with this approach is directly correlated to the layering approach. So in fact, the most common biomechanical complication is the chipping of the prosthetic material that is a layered on the top. And from this point of view, from the clinical data we know how the incidence of chipping ranges from 6% to 36% with a follow up period that ranges from three to 10 years. So it’s a really important variability. And the reason is that to in order to avoid the risk of chipping, it’s really important to take into consideration many parameters, many elements, like the framework design, like the layered porcelain thickness, like the properties of the prosthetic material, and at the same time the cooling down thermal cycles. Like all the steps in the lab from the technical point of view. Today in fact, we know how, in order to reduce the incidence of chip and fracture, it’s really important to perform the framework with an anatomical design, in order to have a good support, in order to have protrusion that can support a uniform thickness in ceramics on the top. Like in this case, how we can see from the peaks where we maintain a really important protrusion on the axial walls in order to maintain a uniform thickness. And this option is absolutely important, not only in case of teeth support rehabilitation, but also in case of implant support rehabilitation. So we know how we don’t have any type of mechanoreceptor from the periodontal ligament. And so this system, from a biomechanical point of view, is more critical. In fact, we know from the clinical data how– also in cases of traditional approaches, like porcelain-fused to metal– the incidence of chipping is absolutely higher in case of implant support rehabilitation than in case of teeth support rehabilitation. And in particular, this topic becomes really important in this type of treatment, where we have full mouth rehabilitation, and where we don’t have any type of mechanoreceptor. I want to show you this, my case which in 2006, one of my first cases with this approach with layered zirconia framework in a full mouth rehabilitation. And this is the pics after the delivery. And this is the image after seven years. It seems to be good. But if I show you in high magnification, it’s clear to observe the number of fractures that are observed. Lots of fabrics. And they try to manage these fractions with composites, with direct restoration, but without predictable results. Because on to zirconia, it’s impossible to have adhesion. It’s impossible to have a good bonding with the composite. And so it’s normal– it’s impossible to not have a predictable result. So it’s impossible to manage with reliability these types of complications. So in order to reduce the incidence of chip or fracture, and at the same time, in order to simplify the treatment, the management of a biomechanical complication, we need a new solution. And this is new solution can be represented by a new approach based on the adhesive combination of the zirconia framework with monolithic lithium disilicate restorations. And this technique– it will be described in the International Journal of Esthetic Dentistry, in the December 2014 issue. This approach can be used in case of single crowns, where we can combine a zirconia abutment with a monolithic single crown. Can be used in case of partial rehabilitation, like in this case where we have a framework in the upper jaw, in the upper maxilla, from lateral incisor that has been created by monolithic crowns. But absolutely can be used in case of full arch, where really, when we have biomechanical complication, is really dramatic. It’s really difficult to manage it from a clinical and also technical point of view. This approach is based on three topics. The first one is the framework design. The second one is the monolithic lithium disilicate manufacturing. And the third one is the pairing technique. About the framework design, it’s really important to have a prosthetic design of the framework, in order to have a vertical path, in order to cement vertically the restoration on the top of the framework. Because the lithium disilicate is a strong material. 400 megapascals of flexural strength. And it means that the he doesn’t need a strong support by the framework. So prosthetic design. Note in an anatomical design, like in case of a traditional layered approach, in case of zirconia or metal framework. In fact, it is for example, the typical framework design that we have in case of layered approach. And anatomical design with protrusions, in order to maintain a uniform thickness of ceramics on the top. While with this new innovative approach, the design is completely different. We have a prosthetic design. And we can see from the slide how we don’t have the protrusion. It doesn’t matter to obtain a uniform thickness on the top. And it’s really clear if we observe this slide, where we assess the same framework from another point of view. We can see in fact, in the case of layered approach, we have an anatomical design. And we maintain a uniform thickness of ceramic on the top. While in the case of lithium disilicate approach, we have a prosthetic design, no protrusion, no undercuts, in order to have a perfect vertical path of the restoration. That it will be cemented by an adhesic combination. Another topic is about the thickness. Because in the case of the layered approach, we have to maintain a uniform thickness of about two millimeters. While in the case of the lithium disilicate approach, we can maintain an also bigger thickness, like a three millimeter occlusion. It’s important to maintain at least 1.5 millimeters in occlusion, and least 0.8 millimeters on the axial walls. But an important topic is to consider the difference in flexural strength between the prosthetic porcelain that we use in the case of the layered approach, and the monolithic lithium disilicate that we use in case of the new approach. In fact, in case of prosthetic porcelain, we have simply 110 megapascal. While in the case of the lithium disilicate, we have 400 megapascals. And absolutely it is a stronger material with respect to the prothetic porcelain. And this is an important thing to consider in order to reduce the incidence of chipping. And now I want just to introduce a topic that we will discuss in the last part of the lecture. In fact, we mentioned to have a chipping on this type of framework. It’s clear that if we have a chipping in the case of the layered approach, normally we have a chipping with a zirconia exposure. It means that we don’t have a big area to watch. And where, to create a good bonding for a composite, order to have a predictable direct restoration for the fracture management. While if we have a chipping, in the case of the monolithic lithium disilicate approach, usually we have a cohesive chipping. So we don’t have [INAUDIBLE] exposure. And it means that we have a big area to watch, a big area where we are to create a good bonding between the composites that we generally use to treat and to manage the biomechanical complications. But we will discuss deeper on this topic in the last part of my lecture. The second topic is about the lithium disilicate manufacturing. We know how the lithium disilicate can be produced with two technologies– press technologies or CAD/CAM technologies. Both techniques are reliable. To be honest, I prefer the press technology. Because with this approach we can fabricate crowns. We can obtain bridge fixes, splinted crowns, three-unit bridges, four-unit bridges, and also six-unit bridges. While in case of CAD/CAM technology, we can simply obtain single crowns or simply three-unit bridges. And it is an important consideration to do, when we have a big treatment, like for example, a full arch. In this case in fact, it’s a more effective approach to use the press technology in order to have the possibility to manage the framework with single crowns, and also three-, four-, or six-unit bridges. The use of lithium disilicate material was introduced by in vitro study in 2010 by Petra Guess, where she assessed the difference between monolithic lithium disilicate crown, versus a hand-layered zirconia crown. And this in vitro study shows how monolithic lithium disilicate material exists until 900 Newtons. While the zirconia crowns have the 200 Newtons, manifested complications, fracture. And these results were also evaluated– it was also described in many clinical studies, like mine– that I published it the only international journal of Peri Restorative Dentistry in 2014– where I assessed 860 lithium disilicate restorations, placed in both the anterior and the posterior segments. And my success rate that I observed ranges from 95% to 100%. And it’s important to consider that in my study population, 33% of the patients had parafunctional habits, severe parafunctional habits. This is an important element to consider in order to speak about reliability of this approach. So it is the reason why we think we decide to use these materials– so the lithium disilicate– also in the case of implant support rehabilitation. So in order to recreate the occlusion on the framework, on the zirconia framework. In the first my experience with this approach, I usually treated the zirconia framework with single crowns. But today in order to do simply technical and clinical procedures, I prefer to treat the framework with bridges, usually four two-unit bridges. In this way we can really simplify all the clinical and technical procedures. It’s really important to design, to fabricate, the crowns or another type of monolithic lithium disilicate restorations with a screw-hole access. In this way, we have the possibility to reach the screw during the application of the rehabilitation in the mouth, in order to have perfectly a screw-retained rehabilitation. And in order to maintain all the advantages that we have in the case of screw-retained based approach. Now I will show you our first case– a full moth rehabilitation with this new and innovative prosthetic approach on the upper and the lower jaw. And I want to show you how we managed the lower framework with a zirconia framework, and a monolithic lithium the disilicate obtained by press technology. And in particular, we have a six-unit bridge in the anterior segment, and two three-unit bridges in the posterior segments. And finally, we obtained a screw-retained rehabilitation. Because we can see how really we can easily reach the screw on the implant in order to have a perfectly screw-retained rehabilitation, maintaining all the advantages we have with this approach. Like for example, the possibility to remove it easily in case of biological complication. Now we can see the esthetic outcome that we can achieve with this approach. Simply, with a staining technique we can see how really it’s possible to obtain good characterization, both in the interior portion, then in the occlusal portion. And from the videos, it’s possible to see the type of occlusion that I obtain in my rehabilitation, anterior and lateral guidance. And it’s also important to assess the natural appearance of this type of result. In particular, if we look at the face of the patient during the smiling and during the phonetics– going natural appearance that is not easy to understand that it’s simply obtained by a staining approach without any type layered material. A second option could be to create this type of approach, but cement with an intra-oral cementation. So to design the lithium disilicate restoration without this screw-hole access, and cement them intra-orally. To be honest, I do not recommend this approach. Because I think that the advantage of the screw-retained rehabilitation is an important feature to maintain in our rehabilitations. And so I recommend this option only in cases where we have an advanced implant angulation. For example, where we have the screw-hole access in the buccal aspect of the anterior teeth, where it’s unacceptable to maintain the screw-hole anteriorly. Because it can really compromise the esthetic outcome. About the framework design– the framework fabrication– it’s important to consider three aspects. The first one is the connector. So the height of the connector, in order to give good strength, a good support to the framework. Secondly, it’s important to consider the height of the abutment, in order to have the possibility to give to the crown or to the restoration a good retention to the framework, through an adhesive cementation. And thirdly is the space for the occlusal reconstruction. That must be at least 1.5 millimeters in occlusion. These parameters are very important to consider, in particular in the case of regular dentures, where we don’t have important vertical height to consider. This is for example a framework that, in the posterior segment, that I treat with one three-unit bridge. And we can see that also with a small space, a poor vertical space, it’s possible to obtain a good result, obtain a good esthetics with 1.5 millimeter in occlusion. In order to have a good natural appearance, it’s absolutely important to use HT ingots. So high-translucent ingots. Because it’s the only material that we can use with this approach. Because if we use more opaque material, it’s impossible to obtain a good natural appearance, from a prosthetic and esthetic point of view. In the case of hybrid prosthesia, the situation is different. Because in this case we have important vertical height. And so in this way we can manage the space from the connectors, from the abutment height, from the occlusal reconstruction differently. In this case for example, I maintain a thickness in an occlusion that is about three or four millimeters. So really bigger than in the case of a traditional approach. And these represent a really important element, a strategic element to consider, in order to manage the biomechanical complication. But we will discuss about this in the part of my lecture. The third option that we have to consider in this treatment with this innovative approach is correlated to the pairing technique, between the framework– so the zirconia– and between the lithium disilicate. And we have two options. The first one is an adhesive approach, an adhesive cementation, so through a resin cement. The second is the CAD-ON technology through crystallization process. So I think that the adhesive approach is absolutely more flexible in this clinical and treatment. Because it’s possible to use in all clinical situations, from the single crown to the full arch. Why? CAD-ON technology can be useful only in case of partial rehabilitation, for example for single crown, or for bridge– three-unit bridge, for example. Because it’s really not recommended when we have to combine one framework with more lithium disilicate restoration. Like for example, one framework with two or three single crowns or bridges. So it’s really recommended for partial rehabilitation, and not for full arch, for example. In the case of adhesive cementation approach, it’s really important to treat the internal surface of lithium disilicate restoration, like in the case of traditional procedures. So in the case of natural teeth, support rehabilitation. So we have to clean the internal surface with alcohol, to etch the internal surface, to clean again, and then to finalize the treatment with the resin cement. It’s really important to consider that we have an important distinction between the cementation of bridges and the cementation all single crowns. Because the topic is that single crowns can have a slight rotation of the framework. So it’s not so easy to cement them in the perfect position, maintaining the occlusion. So this is the reason why I love to perform bridges in the posterior segments. Because in this case, with bridges– like we can see in the video– it’s possible to have a perfect cementation. Because the bridge cannot rotate on the framework. And so in this way, we can cement perfectly the bridge in the posterior segments. We clean the surface of the framework with a heart phosphoric acid simply to clean, without any etching approach. Because we know that on the zirconia it is not possible to etch the surface. We etch with the hydrfluoric acid the internal surface of lithium disilicate. And then we cement with the dual-cements the cementation on the top of the framework, without any risk to do a mistake about the position of the restoration on the framework. We do it because with bridges, it’s impossible to have a rotation. It’s important then to clean the excessive cements with scalar or with microblade in order to remove perfectly the cement from the edentulous area. While, in the case of single units, the situation is different. Because crowns can rotate on the framework, for a reason concerning the feet of this crown, the framework. So it’s really important to have the possibility to recreate the position during a cementation. And so we can use other oscillator or we can use silicone index. We can see from the video, I cement the anterior piece. And then I put the model on the oscillator, in order to verify exactly the position of the crown. And only after this procedure, I go with light-curing in order to start the polymerization of the cement. In this way I’m sure about the perfect position of the crown on the framework. In fact in my first experience with his approach– like we can see in this case, where I performed 14 single crowns on zirconia framework– the cementation was really difficult. Because it’s really difficult to cement 14 crowns on the framework. And in fact in this case, I used silicone index, a rigid index, in order to be sure to recreate perfectly the position of the crowns on the framework. This is the final outcome after the lutein procedure. And this is the final result in the mouth of the patient five years after delivery. And we can see how we have achieved really a good result, from an esthetic point of view. And we can see the good characterization that we obtained simply with a staining approach, both in the interior portion, then in the cervical portion. And remember that, for obtaining this type of result, it’s possible only with HT ingots. So high-translucency ingots are the only material that’s allowed to us to obtain a good natural appearance, only would the staining approach. And pay attention on this slide. Because in this slide, I have summarized about the topic of this technique. And in particular I compare exactly the layered approach with the monolithic approach. So first of all, we have just seen how important this difference is correlated to the flexural strength in occlusion. And we have 100 megapascal for the prosthetic material, and 400 megapascal for the monolithic lithium disilicate. And it means that, in this way, we can really reduce the incidence of cohesive chipping. Secondly, another important topic is correlating to the union that we can achieve between the porcelain and which in the zirconia. Because in fact, we know how in the case of layered zirconia, the bone strength that we can have with the porcelain in the framework is about 10 megapascals. And remember that in case of PFM restoration, this value is superior to 27 megapascals. So we have an important difference between these two approaches, between layered zirconia, and layering metal. So PFM restorations. While in the case of the lithium disilicate approach, we can achieve a union with the framework of at least 25 megapascals in relation to the cement that we use. And so in this way, we can really beef up our rehabilitation. We can really reduce also the incidence of adhesive chipping. So of the chipping with the zirconia exposure, because we can really beef up the strength between the zirconia and between the lithium disilicate. Actually, we don’t have important clinical data about this approach. The only one that we have is by Alessandro Pozzi, a clinical study with a follow up period range from three to five year, where he assessed 18 rehabilitations, with a total number 236 single units. And he observed only one chipping. So he had a success rate of 100%. So absolutely is a good result. But I know that in order to have a good support from the clinical data we need more clinical studies with longer follow up periods, and a big number of clinical cases. So in conclusion, about the advantages of this approach. We have just seen about the biobiomechanical advantages, in terms of flexural strength, in terms of flexural of strength in occlusion. But then the second topic that’s really important with this approach is correlated to the possibility to manage perfectly the biomechanical complications. In fact, which type of biomechanical complication we can observe with this approach? We can observe minor chipping without zirconia exposure, or a major chipping with the zirconia exposure. And how we can treat them? In case of minor chipping, we can use the bonding. And so we can do direct restoration in composites in order to repair the fracture. So I want to show you at this time my complication that I observed, and my experience that has taken into consideration about 41 rehabilitations. I want to show this case, for example. This is a fracture that I observed simply one week after the delivery. Probably is my mistake during the occlusal calibration. And the patient came to my care with a fragment. And so I decided to treat this problem simply through the bonding. So I etched the surface in the mouth of the fractured crown. I etched the internal surface of the fragment, and then I bonded the two components together with the resin cement. And this is the result that I obtained after six years. Still in the mouth, and function, without any type of discoloration or complication. It means that the bonding is absolutely reliable with these two materials. It is the same material– lithium disilicate. Another fracture in the upper, a premolar– a minor chipping only in the premolar. And I treated perfectly in the same way. So with a direct restoration, I etched the surface, I used a sealant, adhesive, and then composite. And this is the result after the procedure, and finally the result after three years. Also, in this case, the restoration is still in the mouth and in function. And to convince you about the reliability of this approach, I want to show you this case. In my clinical case treated in 2005, two Procera crowns on these anterior teeth, dyschromic abutment. I love to use Procera crowns in the anterior segment in case of dyschromic abutment. Because it’s a good material. And it allows us to mask the discoloration, and at the same time, to maintain a good natural appearance. But this was a patient with a severe parafunctional habit. And in fact after two years the patient came to my care with this problem– a minor chipping on the interior edge. So I had to replace again the restoration. And in order to give the patient the possibility to have something more reliable, I decided to use a monolithic lithium disilicate. But in this case, the problem is the dyschromy, the discoloration of the root. And so I’m forced to use a more opaque ingot. And in this case, simply with this staining approach it’s impossible to obtain a satisfactory result. And in fact, the prosthetic outcome that I achieved, it wasn’t satisfactory for me and for the patient also. So I had to remake the restoration again. And in the first time, I thought to remove completely the crown, and to rebuild again a new crown. But I thought that this was a crown that was completely etchable, like the enamel. So I decided to prep the monolithic lithium disilicate crown, like in the case of a tooth. And so I prepared the crown to a similar veneers, a veneer in more translucent material. And I cemented the veneers on the top of the crown, like in the case of restorational procedures in cases of a esthetic treatment. And the cementation also is really similar. The only difference is concerning the acid. Because in this case, I used hydrofluoric acid, and not orthophosphoric acid. But the approach is the same. And this is the result that I obtained after five years. It’s good result and function without any type of complication from a biological point of view. We can see how also in the palatal aspect, we don’t have any type of discoloration or infiltration. And it means that the bonding that we achieved between the lithium disilicate through an adhesive cementation is absolutely reliable. In fact, we can see how after etch, this is how lithium disilicate appears– the same image that we have when we etch the enamel. And also, if we look, the lithium disilicate after etch– in a high magnification with a microscope– we can see this type of image that is really very similar to the image that we have when we etch the enamel. In fact in this light, we have the enamel after etch, and the lithium disilicate after etch. And we can see how from a micro-mechanical point of view, the surface is really seem. So if adhesion is so reliable in case of enamel, of course, probably also with the lithium disilicate this approach is absolutely predictable in lots of clinical situations. And what about major chipping? To be honest in my experience– 41 rehabilitations with this approach– never I observe a major chipping. Because always in this case I observed cohesive chipping without zirconia exposure. And it’s a really strategic point. Because in this way, I have always a big area to watch, and where to create the bonding. But anyway. If I will have a major chipping, I will have the opportunity to remove completely the fractured crown and to replace a new crown. Because I have the possibility to cement on the top with the vertical path the new crown on the framework. And it is an important advantage, in my opinion. I want to show you this case– a fracture or a road accident. Because remember that fracture can happen also for external trauma. And this is what they do. The patient was really worried about this. Because she thought that she’d have to replace, to redo completely the rehabilitation. But I treated in 10 minutes the situation, with composite, with a direct restoration. Because with lithium disilicate we have the possibility to create a good bonding. And then after five months, this is the situation. Still in the mouth, with a good condition. And now we decide to remake completely the new crowns. So we removed the lithium disilicate crown, like in the case of a traditional approach. So we create sulcus. We removed the lithium disilicate. We exposed perfectly the zirconia. We take an impression. We give the impression to the dental technician in order to obtain two new crowns in the monolithic material, lithium disilicate with the HT ingots. And then this is the final outcome. So we have the possibility to repair perfectly the situation. And it’s a really important topic to consider in our clinical practice, both for us, and for the patient. And this is the final outcome after the cementation of the two new crowns. I want also to show you a small video about the technique. So like in case of a traditional prosthesis, we remove the old crown, creating sulcus on the vestibular and palatal aspects. We remove completely the lithium disilicate material, and we expose perfectly the zirconia. Remember that this is a screw-retained rehabilitation. So we have also the possibility to remove the rehabilitation, to arch from the mouth, and to do all this procedure in the lab. But I prefer to do this approach in the mouth. Because I simply need two appointments of one hour for each. So it’s really easy, for a dentist, this type of approach. So after, to remove the lithium disilicate we take an impression. And it’s really easy to take this type of impression. It’s very important to avoid to overheat the framework, for the risk to create a fracture, to create complication inside the framework. And so it’s important to work with lots of water from the instrument. And the impression can be taken simply with silicone, or with polyether. And remember, I repeat– it’s really easy, like impression. Because we don’t have any problem with the soft tissues. In this way, the technician can produce the two new crowns. And in this way, I have the possibility to cement the two new crowns in the mouth of the patient. In this part of the video, we can see the tray in. And I cemented the two new crowns simultaneously, in order to be sure about the position of the two new crowns. So I cemented contemporally the two crowns. I have to evaluate the shape, the color. I want to be sure about the position. And then after that, I check again the position with the occlusion. And finally, I start with the light-curing in order to start with the polymerization of the cement. Then we remove the excessive cement with the scalar, with the microblade, in order to remove perfectly the excessive cement also in the area and border between the lithium disilicate and the prosthetic porcelain, inside the sulcus. And then finally, we have the possibility to replace, to repair, perfectly the rehabilitation. In this phase, for example, we can see the excessive cement from the palatal. And this is the phase of the microblade, where remove perfectly the excessive cement from the sulcus. And then we can see exactly the final outcome after the polishing. And we can see how really it’s possible to achieve good result, good prosthetic integration of these two new crowns. And now I want to invite you to imagine to solve these types of complication in case of the traditional approach, so in cases of porcelain fused to metal, or to zirconia, where additional baking is not recommended, and where bonding procedures aren’t reliable for the minimal ceramic thickness that we have on the top, for the metal that the can compromise the compromise the esthetic outcome. And so, I want really that you pay attention to these aspects of this approach that in my opinion is really important. Because remember that to find the strongest solution in order to give to the patient a reliable result, it’s good. But it’s not really convenient. Because we need strong solution. But in the same time, we need the possibility, the opportunity, to manage perfectly and with reliability the biomechanical complications, if they will happen. Unfortunately we don’t have the possibility to use this approach in all clinical situations. Because from biomechanical reasons, sometimes we are forced to use titanium framework. In particular, like in this case, where we have a [INAUDIBLE] approach, and where we have an important distal cantilever on the right side. But anyway, we can treat this patient with the same approach, with a prosthetic design of the framework– with titanium, and not zirconia– and with monolithic lithium disilicate restoration cement on the top. We can see in fact in this case how we have a zirconia framework in the upper jaw, and a titanium framework in the lower jaw. The only difference is correlated to the framework, in relation to the necessity to put an opaque material on the top of the abutment in order to mask the discoloration. And in this case, I prefer to use an opaque material for composite. And the second difference is correlated to the necessity to recreate the soft tissues, the pink tissues, with composite, and not with layered ceramics, with prosthetic ceramics. And it means that we have the risk to have pigmentation after many years, after delivery, in particular in patients that are big smokers. But anyway in this case, the patient isn’t a smoker. And in fact after one year, we have a perfect stability of the prosthetic, and of the esthetic outcome. This is integration of my rehabilitation in the face of the patient, and in the smile of the patient. And we can see how really it’s possible to achieve a good esthetic integration simply with a staining approach, without any layered approach and any type of prosthetic material. I want to show you a small video about this patient concerning the delivery of their rehabilitation. We can see now the esthetic integration, the good natural appearance of the this type of prosthetic treatment. And it really is difficult to find that we don’t have any type of prosthetic material layered on the top of the framework. But really, we can see how– thanks to the HT ingots and the good staining approach– it’s possible to achieve a good integration. And we have seen in fact, in the video, the good natural of the prosthetic outcome. So in conclusion, I want that you pay attention on the typical question that our patient had before to start with a new treatment. And the question is, Dr., for how many years can you assure me this treatment? And really, it’s a difficult answer for us. Because we know how it’s really difficult to find a good answer. It’s difficult for us to give a number. Because all the patients are different from biomechanical and biological point of view. But in this case, in implant support rehabilitations, for me, we have a solution. Because my answer is, that for me it’s difficult to give to the patient a number. But anyway, don’t worry. Don’t worry, because we have really the possibility to manage perfectly the complications. And these represent really an important advantage, both for us and for the patient. Actually, the lithium zirconia– it seems to be the “go to” solution in the future. Yes it’s absolutely the strongest option that we can have in our dental practice. But with the monolithic zirconia, we don’t have the possibility to manage it, in case of biomechanical complication. Because we don’t have the adhesion. We don’t have the bonding. And we don’t have the possibility to manage easily in the mouth. Because it’s really a hard material. So remember, strong material, but in the same time the possibility to manage it perfectly in the mouth in case of biomechanical application. Thank you very much for your kind attention.