Effect of speed sintering process on the microstructure, flexural strength and translucency of zirconia

Objectives: To determine the impact of the speed sintering program on the microstructure, flexural strength and translucency of zirconia in comparison with those of the conventional sintering program. Materials and methods: rectangular shape specimens (12.5 x 15.5 x 1.2 mm) were prepared from four commercial pre-sintered zirconia ceramics (KATANA HTML, KATANA STML, InCoris TZI and InCoris ZI) that were sintered with conventional and speed sintering programs according to the manufacturer's instructions. The phase composition of the sintered specimens was determined by X-ray diffraction (XRD). The grain size was evaluated using scanning electron microscopy (SEM), while the three-point flexural strength was assessed based on the ISO 6872: 2015 standard. Translucency was assessed using a spectrophotometer. The data were analyzed using independent t tests (alpha = 0.05) and one-way ANOVA. Results: The XRD patterns were similar for all the groups, indicating that there was no phase transformation. SEM revealed that the average grain size was lower than 1 mu m. The grain size, flexural strength and translucency results showed increasing trends when speed sintering is compared with the conventional one but the differences were not significant (P > 0.05). Conclusions: The results of this research indicate that the speed sintering program had no significant impact on the microstructure, flexural strength and translucency of the examined zirconia, a speed-sintering program can process the ceramic material within a short time with slightly increase their flexural strength and translucency Therefore, a speed-sintering program is appropriate for zirconia (Y-TZP).