evaluation of translucency and biaxial flexural strength of different ceramic materials.

Objective: To evaluate Translucency and Flexural strength of four ceramic materials Lithium disilicate (Emax), translucent zirconia (Bruxizir), Ultra translucent zirconia (Katana ST) and Zirconia reinforced lithium silicate (Suprinity), using two thickness, 0.5 mm and 1mm. Materials and Methods: Blocks of four CAD/CAM esthetic restorative materials (emax, suprinity, bruxzir and katana) were used to prepare 80 samples (disks) with the following dimensions: 10mm x 0.5mm and 10mm x 1mm for suprinity and emax ceramic material & 12mm x 0.6mm and 12mm x 1.2mm for Bruxzir and katana ceramic material. Using IsoMet 4000 micro saw by a diamond disk 0.6 mm thickness with cutting speed 2500 rpm. Then all the disks were crystallized and sintered. One Ceramic disc of each material were examined under a Reflective spectrophotometer (Model RM200QC, X-Rite, Neu-Isenburg, Germany) to determine the translucency for each disk. After that each disk was subjected to a biaxial flexural strength test. Results: For translucency test, at 0.5mm the highest value was found with Vita Suprinity (21.71±1.59), followed by Emax (17.89±3.47), then Bruxzir (13.27±1.86) while the lowest value was found with Katana ST (11.57±2.45). while at 1mm the highest value was found with Emax (14.78±1.63), followed by Vita Suprinity (14.65±1.58), then Katana ST (10.59±2.16) while the lowest value was found with Bruxzir (10.42±1.56). Otherwise for biaxial flexural strength, at 0.5 mm the highest value was found with bruxzir (194.04±59.50), followed by Katana ST (191.66±63.71), then suprinity (163.96±28.86), while the lowest value was found with Emax (113.70±26.76). while at 1mm the highest value was found with Katana ST (605.47±115.98), followed by Bruxzir (588.40±111.39), then Emax (474.62±68.36) while the lowest value was found with Vita Suprinity (419.50±76.96). Conclusion: Increasing thickness affect the flexural strength of ceramic material positively, while it affects the translucency negatively except for katana. Different ceramic material exhibited variable translucency and flexural strength values depending on their composition. Lithium disilicate materials show more translucency and lower flexural strength than zirconia materials.