Future Dental Journal of Egypt


Purpose: The objective of the study was to investigate the effect of different immersion times, in coloring liquid, and sintering temperatures on translucency of monolithic nanocrystalline zirconia. Materials and methods: Forty five specimens of nanocrystalline zirconia were obtained by cutting InCoris TZI blocks into slices using a stainless steel disc mounted on a custom made milling machine. The slices were divide into three groups (n ¼ 15) according to immersion times (3,5 and 7 min) then each group was further subdivided into 3 subgroups (n ¼ 5) according to the sintering temperatures (1400 c, 1500 c and 1600c). CIE-Lab coordinates were measured for each slice against black and white backgrounds using Vita easy shade spectrophotometer and translucency parameter (TP) was calculated. One way analysis of variance combined with a Tukey-post hoc test were used to analyze the data obtained (P ¼ 0.05). Results: Results of the present study showed that at temperature 1400 c there was statistically significant decrease in TP between 7 min immersion time and the other two groups, while there was no statistically significant difference in TP using different immersion times at temperatures 1500c and 1600c. Conclusion: Our results showed that the best translucency was obtained by the combination between lower dipping times and higher sintering holding temperatures.