Evaluation of colour reproduction of CAD/CAM Lithuim-disilicate Evaluation of colour reproduction of CAD/CAM Lithuim-disilicate veneers of different thicknesses and translucency

Background: With the increasing patients’ demand for a perfect smile, the call for highly aesthetic and yet minimally invasive veneers has surmounted. Objective: The aim of this study was to evaluate the colour of CAD/CAM lithium disilicate veneers fabricated in different thicknesses and different translucencies of the lithium disilicate blocks. Materials and Methods: Forty discs of lithium disilicate glass-ceramic (IPS e.max CAD) of shade A1 of both high and low translucency (HT, LT) were tested for their colour reproduction. HT and low LT blocks were cut in the form of plates of dimensions (12 x 14 mm) and of different thicknesses (0.3 mm, 0.5 mm, 0.7 mm, and 0.9 mm). Twenty specimens of each translucency were classified into three sub-groups according to thickness (n=5). Colour reproduction (∆E) was determined using VITA Easyshade Advance against a foundation block and compared with A1 shade tab. Data was collected for statistical analysis. Analysis of Variance (ANOVA), and pair-wise comparison tests were used. Significance level was set to PResults: Two-way ANOVA test showed that the change in both thickness and translucency a well as the interaction between them had a significant effect over (∆E) values. One-way ANOVA and Bonferroni’s tests showed that the low translucency samples showed a statistically significant difference in (∆E) values between all thickness groups except between the 0.3 mm and 0.7 mm as well as between the 0.5 mm and 0.9 mm thickness specimens. High translucency specimens showed a significant difference between all thicknesses. Conclusions: The final colour of laminate veneers could be highly affected by both the thickness and translucency of the ceramic material used. LT specimens produced much better color reproduction with better masking ability than the HT specimens.