Evaluation of aesthetic, mechanical and physical effects of food-like solutions on ceramic materials with different contents used in CAD/CAM systems

Objective: To evaluate the changes in the aesthetic, mechanical, physical and viscoelastic properties of engravable blocks with different contents used in CAD/CAM systems, which are frequently preferred in fixed prosthetic applications due to both aesthetic and functional deficiencies, after soaking in food-like solutions. Method: One indirect composite (Gradia Plus) and six different CAD/CAM blocks (Brilliant Crios, Shofu Block HC, Cerasmart 270, IPS Empress CAD, VITA Mark II, IPS e.max CAD) were used to prepare 224 specimens of 1.2 mm thickness and randomly divided into 28 subgroups to be soaked in 4 different food-like solutions (distilled water, ethanol-water, citric acid and heptane). At 3 different time periods (T0, T12 and T60), the aesthetic, mechanical, physical and viscoelastic properties of the samples were evaluated. Data were analyzed using SPSS 25.0 (IBM SPSS Statistics 25 software (Armonk, NY: IBM Corp.)) package program. Kruskal Wallis Analysis of Variance (post hoc: Mann Whitney U test with Bonferroni correction) was used to examine differences between groups, Friedman Test (post hoc: Wilcoxon paired two-sample test with Bonferroni correction) was used for dependent group examinations, and Spearman correlation coefficient was used to examine the relationships between numerical variables. In all examinations, p<0.05 was considered statistically significant. Results: There was a statistically significant difference between the roughness, color, gloss and microhardness changes at time intervals between one indirect composite and six different CAD/CAM ceramic materials soaked in four different food-like solutions in our study (p<0.05). After examination of viscoelastic properties by dynamic mechanical analysis, the highest damping capacity was observed in resin-containing materials, while glass matrix ceramics showed significantly lower values. It was found that the damping capacity decreased with time in all materials. Conclusion: Food-like solutions had negative effects on all materials used in the study, causing increased roughness and coloration, decreased gloss, microhardness and damping capacity. Key words: cad/cam restorative material, roughness, color stability, gloss, microhardness, dynamic mechanical analysis