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Dental Tribune Middle East & Africa Edition No.2, 2016

Dental Tribune Middle East & Africa Edition | 2/2016 18 restorative Fig. 14: Two weeks after the restorations had been seated: optimal situation withsuccessfulpinkandwhiteesthetics Figs15 to17:All-ceramicrestorations:integratedharmoniouslyandunobtrusivelyinto thedentitionandfacialappearanceof thepatient MarkoJakovac,DMD,MSc,PhD Assistant Professor Department ofFixedProsthodontics SchoolofDentalMedicine UniversityofZagreb Gunduliceva5 1000Zagreb,Croatia MicheleTemperani,CDT LaboratorioOdontotecnicaTemperani ViaLivorno54\2 50142Florence,Italy ◊Page17 Fig.8:Anterior teethpreparedfor thefinalrestoration Fig. 11: Restorations after having been milled from pre- shadedZenostarT1zirconiamaterial(WielandDental) Fig. 12: Molars were created in full contour and the vestibular aspects of the premolarswerelayeredover. Fig.13:Frontalviewof thecompletedrestorationson themodel Fig.9:Themastermodelsweredigi- tizedtocreatethefinalrestorations. Fig. 10: Virtual construction based on the situation created by the long-term temporaries Fig. 6: Long-term temporaries were instrumental in stabilizing the vertical di- mensionofocclusion. Fig.7:Afterlong-termtemporization:abiterecordwastakentodocumentthe occlusalpositioncreatedin thecourseoflong-term temporization. Creatingthefinalrestorations We used the Zenotec CAD/CAM system and Zenostar® zirconia ma- terials (Wieland Dental) to fabricate full-contour crowns and bridges for the premolar and molar region. The plan was to customize the premolar restorations with IPS e.max® Ceram veneering ceramic using the layer- ing technique. The anterior restora- tions were manufactured using the press technique with IPS e.max Press lithium disilicate glass-ceramics. These restorations were also custom- ized using IPS e.max Ceram. On the one hand, the final restorations had to be manufactured in such a way that they were faithful to the param- eters established in the simulation models. On the other hand, the final restorations should reproduce the shape and occlusal dimension of the temporaries, which had been con- sistently optimized during the long- termtemporizationstage.Toachieve an ideal outcome, the laboratory was provided with a range of useful data to allow the technician to mount the models on the articulator and to in- terchangethemwithoneanother: -Impressionsformastermodels - Impressions of the temporaries after functional and occlusal adjust- ments -Occlusalrecord -Facebow The master models and the models of the most recently modi- fied temporaries were scanned and uploaded to the 3Shape software program using the “cross-mount- ing” method (Figs 9 and 10). Given the level of complexity involved in this case, we preferred to mill the components first from wax to be able to assess the quality of the virtual construction in a conven- tionalfashion.Withthisinexpensive method, we were able to assess the shape and function of the structures in“reallife”. In the present case, we noticed that a few areas had not been prop- erly contoured in the wax. These ar- easwerecorrectedaccordingly. The corrected STL data were pro- cessed in the CAM module and the data required for the milling pro- cess imported into the program of the Zenotec mini milling unit. The restoration was then milled from a pre-shaded Zenostar zirconia disc (shade T1) (Fig. 11). It is an advantage of this material that it is supplied in discs that are pre-shaded. Nor- mally, framework shading requires a separate working step to apply metal-oxide based colouring liquids either by an immersion or brush-on technique prior to sintering. In pre- shaded discs, the shades are added to the zirconia powder and homog- enised during the industrial produc- tion process. The result is a material thatdemonstratesahighlyhomoge- neousshade.Astheneedformanual shading is eliminated, time savings can be gained in the fabrication of restorations, providing an additional advantage. Colour consistency is an- other advantage that should not be underestimated. A consistent colour is achieved, irrespective of the skills andexperienceofthetechnician. To ensure an optimum integra- tion of the posterior restorations made of zirconia and the anterior restorations made of lithium dis- ilicate, the vestibular areas of the premolars were layered over with a veneering ceramic (IPS e.max Cer- am) (Fig. 12). We used a conventional press technique in conjunction with IPS e.max Press ingots (shade LT A1) tofabricatetheanteriorlithiumdisil- icate restorations and then complet- ed the pressed crowns individually usingthecut-backtechnique(Fig.13). Seatingtherestorations CAD/CAM technology was used to fabricate the posterior crowns and bridges from monolithic zirconia. The occlusal conditions established in the long-term temporaries were accurately taken into account. Prior to seating the final restorations, we checked their accuracy of fit and shade match intraorally using glycerine-based try-in pastes (Vari- olink® Esthetic Try-In). The crowns and bridges were permanently ce- mented using the dual-curing luting composite Variolink Esthetic DC. In themandible,theveneerswereluted using the light-curing variant of the same luting composite (Variolink Esthetic LC) in a neutral colour. This lutingcompositeiseasytoapplyand excess material can be effortlessly removed during the cementation process. Two weeks after the restorations had been placed, the patient came for another visit to our practice. Pink and white esthetics was harmoni- ously balanced (Figs 14 to 17). This outcome was possible due to the careful adaptation of the treatment to the needs of the patient and the smooth communication between practiceandlab. Conclusion Successful treatment of young pa- tientswithcomplextreatmentneeds requires a high degree of accuracy and minimally invasive prepara- tion methods. Full-contour zirconia restorations milled using CAD/CAM strategies provide a straightforward method to achieve accurate restora- tions, particularly for the posterior region. The success of anterior resto- rations continues to depend largely on the skills of the technician and on the use of materials with optimum properties, such as the IPS e.max lithiumdisilicateglass-ceramics.

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