Evaluation of the effect of different color resin cements and different abutment types on the final optical properties of monolithic zirconia

The aim of the study; to evaluate the optical properties of new generation 3Y-TZP monolithic zirconia's (MZ), with different abutment types and different resin cement colors. A1/LT MZ blocks (IPS e.max ZirCAD, Ivoclar Vivadent) were used in our study. Samples (N=30) of 1mm thickness were obtained from blocks with a cutting device (Microcut 125 Low Speed Precision Cutter, Metkon). Cement groups; transparent (T), yellow (S) and opaque (O); abutment groups were determined as Group Z (zirconia), Group H (hybrid), Group T (titanium) and Group AT (anodized titanium-yellow). L0*, a0*, b0* values of veneers; L1*, a1*, b1* values of veneers with abutments and L2*, a2*, b2* values of cemented veneers with abutments were recorded with a colorimeter device. Color differences; (∆E00*)1 (veneer with abutment+veneer), (∆E00*)2 (veneer with abutment+cemented veneer) and (∆E00*)3 (abutment+veneer with abutment+cemented veneer) were calculated according to the CIEDE2000 formula. Statistics were made with 2- way ANOVA and Paired Sample T-Test (p˂0.05). Significant differences were found between L*, a*, b* and ∆E00* values (p<0.001). Only b* values didn't show significantly differences according to cement*abutment factor (p>0.05). L1* values; showed significant differences between all abutment groups (p<0.001). The highest L1*, L2*, b1* and b2* values were detected in Group H. The lowest ∆E00* values were detected in; (∆E00*)1=0.49 (Grup Z-Tr), (∆E00*)2=0.68 (Grup Z-S), (∆E00*)3=0.64 (Grup Z-S). The highest ∆E00* values were detected in; (∆E00*)1=5.50 (Grup AT-S), (∆E00*)2=4.26 (Grup T-Tr), (∆E00*)3=5.24 (Grup AT-O). Color changes according to the abutment; Group Z-Tr and Group Z-O was 'perceptible'; Group Z-S and Group H was below the clinically 'acceptable threshold'. Color changes according to the cement; 'perceptible' color differences were seen in Group Z-S; Group Z-Tr, Group H-S, Group T-O ve Group AT-O showed below the 'acceptable threshold'. In cases where it is desired to modify the color aesthetically, it should be taken into account that the cement color factor will be also effective with different abutment types together.