Monolithic Zirconia in the Anterior Region, the Palatal Layering Technique: An In Vitro Study

Description :

The ND4 shade of the Natural Die Shade Material shade guide will be scanned in order to design an overlapping layer of IPS e.maxZirCAD Prime. 30 layers of thicknesses 0.5 (ND0.5) , 1 (ND1) and 1.5mm (ND1.5) will be milled and positioned on the die ND4. the pontic will then be milled using the same monolithic zirconia material. The pontics and restored abutments from each group will be placed on a black then a white background. three measurements L*a*b* will be made using a spectrophotometer. The TP will be calculated and compared to threshold values. ΔE will also be calculated in order to determine the color difference between the restored abutment shade or between the different thicknesses.ΔE will then be compared to acceptability and perceptibility thresholds. The comparison that will be done between the different TP values will indicate which thickness of the restored ND abutments, and of the pontics (whether layered or control) represents the highest translucency. Afterwards, the ΔE calculations will permit us to evaluate if a possible color difference is detectable by the naked eye between the pontic (with and without palatal layering) and the restored abutment, as well as between the different thicknesses, and finally compared to the chosen end-shade.