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ePaper created 2015-09-09, 12:07:54 | version 1.38.0
industry report _ composite restorations I millingmachinefromTizian Blank zirconium dioxide (Fig. 9b). Trying on the plas- ter model showed a perfect fit (Fig. 10). Thus, try-in in the patient’s mouth was not necessary, and the abutments were perma- nently attached (Figs. 11a & b). _The way to definitive crowns In order to prepare for fabrication of the definitive crowns, the plaster models were scanned with the mounted titanium adhe- sive bases and abutments (Figs. 12a & b). The software again generated the design suggestion for the three crowns (Figs. 13a & b). These were viewed and measured from every angle. This applied partic- ularly to the occlusal relief and the basal side (Fig. 14). For later finishing with veneer com- posite, the crown constructions were slightly reduced cervically and occlusally. After this ad- justmentandapproval,thenext,fullyautomated, step was the creation of the STL datasets and the nesting of the crowns (Fig. 15). The milling procedure was then performed using a Tizian Zirconia Reinforced Composite blank in the A3 shade (Fig. 16). It was dry milled, without water- cooling. The blank received a code for patient identifi- cation. This means that several jobs can be per- formed at the same time without confusion. As the data for nesting are archived, it is possible to use the same blank again later. The fit of the milled crown fully satisfied ex- pectations. Finally, a razor-thin layer of dialog Occlusal was applied in order to give the restora- tion the bionic function (Figs. 17 & 18). Cervical, dentine and incisal masses were used to give the restoration a certain vivacity. This should be discrete, and the obtained shade was to mirror the colour of the natural teeth. The patient did not want the fissures to be coloured (Figs. 19a & b). Integration in the patient’s mouth took place to the satisfaction of everyone in- volved; the implant restoration was harmo- niously incorporated into the remaining denti- tion (Fig. 20). _Discussion Thebionicrestorationmaterialsystem,madeof Tizian Zirconia Reinforced Composite framework material and dialog Occlusal veneering composite, counters in particular the chipping problem of ve- neered zirconium dioxide. This especially becomes a factor for implants, as the masticatory forces are particularlyhighandtherestorationisaccordingly placed under high strain. Furthermore, the ques- tions of increased wear of natural antagonists and of the effect on the jawbone and the temporo- mandibular joint remain. In this case, it appears to be appropriate to select implant restorations from materials that can create a buffer effect; this is the case for Tizian Zirconia Reinforced Composite in combination with dialog Occlusal. In comparison with zirconium dioxide, the modulus of elasticity of Tizian Zirconia Reinforced Composite is low at 3,050 MPa, meaning the material iscomparativelyelastic,and the Vickers hardness is 196 MPa.Ittakesonthefunction of natural dentine in the re- storation. In contrast, the veneer composite is harder —just like natural enamel. The system of bionic re- storation achieves a Vickers hardnessof560MPa,where- as the Vickers hardness of natural enamel is around Figs. 17 & 18_Crowns milled from Tizian Zirconia Reinforced Composite with a thin coat of dialog Occlusal. Figs. 19a & b_The shape and colour of the finished crowns. Fig. 20_Appearance in the patient’s mouth. Figs. 21 & 22_Maxillae fully rehabilitated with a bionic restoration made from Tizian Zirconia Reinforced Composite with thinly applied dialog Occlusal. The patient really appreciated the buffer effect. I 45CAD/CAM 3_2015 Fig. 19b Fig. 18 Fig. 20 Fig. 17 Fig. 19a