Marginal Adaptation and Internal Fit of Posterior 3-Unit Zirconia FPDs Fabricated with Different CAD/CAM Systems

Purpose: the aim of this study was to investigate the effect of shading on translucency and mean grain size of three Zirconia systems (Lava Frame, Ice Zirkon Translucent and Prettau Zirkon). Materials and Methods: specimens pigmented in A1, A4 and a non-pigmented specimen was evaluated with Scanning Electron Microscopy and spectrophotometery. Results: the transmittance ranged between 0.18 and 0.52, in Ice Zirkon Translucent A4 and Prettau Zircon non-pigmented, respectively. The pigmentation A1 and A4 significantly reduced the light transmission in all the systems evaluated (p<0.05), with the exception of Lava A1. The light transmittance of each ceramic system is different from each other in the three pigmentations, except for the Prettau Zirkon A1, which did not show a significant difference compared with Lava A1 (p>0.05). The mean grain size increased with pigmentation. The mean grain size ranged between 0.43 μm, for Prettau Zirkon non-pigmented, and 0.82 μm for Prettau Zirkon A4. Conclusion: Light transmission and mean grain size was affected by pigmentation of dental zirconia ceramics.