Effect of thickness on color and translucency of a multi-color polymer-infiltrated ceramic-network material

Objectives To evaluate the effect of thickness on color and translucency of a multi-color polymer-infiltrated ceramic-network (PICN) material. Methods Specimens of 0.5, 1.0, 1.5 mm thicknesses were obtained by sectioning VITA ENAMIC (R) multiColor (E-MC) High Translucent CAD-CAM blocks (1M1-HT, 1M2-HT, 2M2-HT, 3M2-HT, and 4M2-HT). Spectral reflectance and color coordinates were measured on white and black backgrounds using a spectroradiometer, CIE D65 illuminant and CIE 45 degrees/0 degrees geometry. CIEDE2000 color and translucency differences (Delta E-00 and Delta TP00) between thicknesses and adjacent layers were evaluated using their respective 50:50% perceptibility and acceptability thresholds (PT00 and AT(00)). Results In general, Delta E-00 between thicknesses for all shades and layers were above AT(00) in general. Chroma decreased from cervical to incisal layers with statistically significant differences (p < 0.05), and Delta E-00 between sequential layers were above PT00, for all shades and thicknesses. TP00 decreased from 0.5 to 1.5 mm and increased from cervical to incisal layers for all shades with statically significant translucency differences (p < 0.05). In general, for all thicknesses, TPT00 < Delta TP00 < TAT(00) for sequential layers. Conclusions The gradient in color and translucency of E-MC PICN material was influenced by the thickness of the CAD-CAM block. In addition, color and TP transition values between the layers depends on the thickness and shade. Clinical significance The effect of thickness must be taken into account by dental technicians and dentists when CAD-CAM multicolor PICN materials are used.