AIM: This study aimed to evaluate the efficiency of the CIELAB and CIEDE2000 formulas for measurements color change of lithium disilicate (LD) and zirconia reinforced lithium silicate (ZL) ceramics after immersion in different mouthwashes.
MATERIALS AND METHODS: Fifty disc shaped samples (5X2mm) were prepared, 25 samples for each group, LD (Group A): E-max and ZL (Group B): Suprinity. The samples were subdivided into 5 subgroups (n=5) according to the immersion type; distilled water, chlorhexidine, iodopovidone, green tea and whitening mouthwashes, for subgroups I-V respectively. Samples were stored separately in their corresponding immersion solution. The samples were evaluated by clinical spectrophotometer before and after immersion. Changes in color (ΔE) were calculated using CIELAB and CIEDE2000 1:1:1 and 2:1:1 formulas. Then, comparisons between ΔE values versus corresponding acceptable threshold (AT) and correlation between them were calculated.
RESULTS
The comparisons by one sample t-test for the values of ΔElab, ΔE2000 and ΔE20002 versus their corresponding AT displayed significance between ΔElab values and AT in subgroups III-V in group A and III and V in group B. A significance difference between ΔE2000 values and AT displayed in subgroups III and V for both groups. The ΔElab, ΔE2000 and ΔE20002 values showed significantly strong positive correlation between each other.
CONCLUSION
The ΔE20002 was more efficient than ΔElab and ΔE2000. Using iodopovidone and pyrophosphate based mouthwashes could cause more dramatic changes in color of LD higher than ZL. Despite the strong correlation between ΔE values, ΔElab cannot always be used to estimate ΔE2000 and ΔE20002 findings.