Influence of Different Thicknesses of Advanced Lithium Disilicate Ceramic on The Color Changes Over a Dark Substrate (An in-vitro study)

Saleh, Areej Zakareya; El Mahallawi, Omaima; Awadallah, Karim

doi:10.21608/acdj.2025.390007.1037

Influence of Different Thicknesses of Advanced Lithium Disilicate Ceramic on The Color Changes Over a Dark Substrate (An in-vitro study)

Document Type : Original Article

Authors

¹ Fixed department, faculty of dentistry, Cairo university, Cairo, Egypt

² Fixed department, faculty of dentistry, Cairo University, Cairo, Egypt

10.21608/acdj.2025.390007.1037

Abstract

Objective:This study aimed to evaluate the effect of varying thicknesses of Two lithium disilicate ceramics on the final color outcome when placed over a dark background.
Materials and Methods:30 rectangular-shaped 12x14mm samples of advanced lithium disilicate (Cerec Tessera) and lithium disilicate ceramic (e.max).Samples were prepared using a CAD/CAM milling machine and categorized into two groups;(LiSi E&LiSi T)and into three subgroups according to different thicknesses 0.5 mm,1mm,and1.5mm with (n=5/subgroup).A Complete image spectrophotometer(UltraScan PRO, HunterLab)was used to measure the color difference(ΔE)when the specimens were placed over a dark composite substrate(shadeA3.5) compared to a standard shadeA2.Intergroup differences were analyzed using independent t-tests, while intragroup comparisons were conducted with repeated measures ANOVA and Bonferroni-adjusted pairwise tests.Variable interactions were evaluated by two-way ANOVA, and overall group comparisons, irrespective of variables,were performed using one-way ANOVA followed by Tukey’s post hoc test.
Results:Lisi T consistently exhibited significantly lowerΔE values than Lisi E at all thicknesses (P< 0.05),indicating superior masking ability.Within each material, increasing thickness resulted in a significantly reduced color difference (P< 0.001).Two-way ANOVA confirmed significant effects of material and thickness on color difference, but no significant interaction effect. Overall,LiSi T at1.5mm showed the least perceptible color change,supporting its use in esthetically demanding restorations.
Conclusion:Within the limitations of this study,LiSi T demonstrated better color outcome than LiSi E,particularly at greater thicknesses.The material and thickness both played a role in determining the color difference,with thicker materials showing more consistency in color.Overall,material choice and thickness are key factors to consider when aiming for optimal aesthetic outcomes in dental restorations.

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