Future Dental Journal


Aim of the study: This study was carried out to evaluate the effect of various sintering protocols on the translucency of highly translucent cubic zirconia. Materials and methods: A total of forty discs of two types of zirconia ceramics were used in this study. The specimens were divided into two main groups according to the type of zirconia; Group 1 (n=20): Cubic zirconia (DD Cube X2 98color) and Group 2 (n=20): Tetragonal zirconia (BioZX2color). Each group was subdivided into two subgroups, where 10 discs were per subgroup according to the sintering protocol. Cubic and tetragonal zirconia blanks of dimensions (98 mm diameter × 25 mm thickness) were CAD/CAM milled into cylindrical-shaped blocks of dimensions (15 mm diameter × 25 mm thickness). Cylinders of both materials were cut with a diamond cutting saw into discs with larger dimensions (15 mm diameter × 1.2 mm thickness) to compensate for the approximately 23% shrinkage of the material during sintering, so as the final dimensions would be (12 mm diameter × 1 mm thickness). Discs were dried under a heating lamp and then conventionally and speed sintered according to the manufacturer's instructions. The translucency of each subgroup was evaluated by measuring contrast ratio (CR) and translucency parameter (TP). Results: For both cubic or tetragonal zirconia, conventional sintering showed statistically significantly lower mean CR and higher mean TP than speed sintering (P-value <0.001). Conclusion: Different sintering protocols showed a significant effect on the translucency of cubic and tetragonal zirconia.