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ePaper created 2016-06-17, 10:57:49 | version 1.38.0
aesthetic restorations case report | 23CAD/CAM 2 2016 the disc. In the next step, the unsintered bridge was customised with colouring liquids using the infil- tration technique. The range of Zenostar Color Zr liquids is perfectly suited for this purpose, as they are supplied in the standard shades of the A–D shade guide. Five Effect shades are available for further customisations. We used Zenostar Color Zr in shades A2 and A3 as well as the grey-violet Effect shade. In order to render the infiltration of the individual liquids visible, the virtually colourless liquids were mixed with a visualizer (Zenostar VisualiZr). First, the interior surfaces of the crowns and the basal surface were infiltrated; followed by approx. 1 mm of the cervical margin, the fissures and the central areas of the palatal surfaces. Infiltration of all these aspects was achieved with Zenostar Color Zr A3 mixed with yellow Zenostar VisualiZr (Fig. 6). After that,thedentinareauptotheincisalthirdwasinfil- tratedwithshadeA2mixedwithredVisualiZrliquid. The incisal area of the anterior teeth and the cusps of the posteriors were customized with a diluted version of grey-violet Effect shade and Zenotec Color Optimizer mixed with blue VisualiZr liquid (Fig. 7). It is essential to use a separate brush for each shade. After having been allowed to dry for two hours, the framework was sintered in the Programat S1. After the sintering process, the restoration exhib- ited an excellent accuracy of fit, without the need for any adjustments by grinding, e.g. on the insides of the crowns. The advantages of the translucent zirconium oxide became obvious at this stage. Owingtothecolouringliquids,thecervicalandden- tin areas were beautifully accentuated. The incisal areas exhibited a slight greyish-translucent sheen, which should facilitate the subsequent layering procedure(Figure8showsthesmoothtransitionof the shades). The simulation in Figure 9 demonstrates how diffi- cultitwouldhavebeenforustoachievethedesired toothshadeifwehadusedopaquewhitezirconium oxide for the framework. Despite the high translu- cency of the zirconium oxide, the titanium abut- ments did not show through the framework. Individual framework refinements An optimum aesthetic outcome is only achieved if the restoration exhibits ideal optical properties. A controlled brightness value, adequate saturation andtranslucencyandminimisedlightreflectionare essential to achieve a pleasing aesthetic outcome. Iftheseparametersarenotmet,theresultwillnever be satisfactory, even if the restoration is veneered with ceramics. The result would simply be a resto- rationthatlooksgoodonthemodelbutappearstoo bright in the mouth. Staining the zirconium oxide prior to sintering is the first measure to control the light reflection ef- fects. Application of a liner is the second measure. The bridge was veneered with IPS e.max Ceram. Astheframeworkalreadyexhibitedapleasingbasic shade, we applied a mixture of IPS e.max Ceram ZirLiner Clear and Incisal (70:30). ZirLiner Incisal reduces the light reflection of zirconium oxide; alternativelyLiner4maybeused.Inordertomixthe liners, IPS e.max ZirLiner BuildUp Liquid was added. Theresultwasamixturewithapleasingconsistency that would ensure an even coating. After the firing process, the restoration exhibited a homogeneous surface and an adequate level of fluorescence. For the foundation firing of large restorations, we prefer the layering technique rather than the sprinkletechnique.Thelayeringtechniqueprovides Fig. 11: ...the vestibular anterior surfaces were veneered individually. Fig. 12: After final firing: the monolithic crowns did not appear brighter than the veneered crowns. Fig. 13: Finished bridge: harmonious shade effects and homogeneous surface texture. Fig. 14: The cemented bridge pleases with its beautiful natural appearances... Fig. 11 Fig. 12 Fig. 13 Fig. 14 22016