Evaluation of shade matching in the repair of indirect restorative materials with universal shade composites
Purpose To evaluate color differences in repair of indirect ceramic and resin nanoceramic CAD/CAM blocks with two universal shade composites after different surface preparations. Materials and Methods 120 samples were prepared from IPS Empress and GC Cerasmart270 CAD/ CAM blocks and thermocycled (5000 cycles, 5°C–55°C). Initial colors of sample surfaces were measured using a spectrophotometer. Rectangular prism-shaped cavities were prepared and repaired with Tokuyama Universal Bond/Omnichroma and G-Multiprimer/G-Premio/Essentia Universal following surface preparation with aluminum oxide, Cojet, and bioactive glass (Sylc). Repaired samples were thermocycled (5000 cycles) and color measurement was performed. Color coordinates L*a*b* were recorded, and color differences were calculated using the CIELab formula. Color differences between pre-and post-repair (∆E1) and between post-repair and post-aging (∆E2) were determined. Data were analyzed using Three-way ANOVA with a significance level set at p<0.05. Results ∆E1 values in all subgroups exceeded the threshold of 3.3. No significant difference was found between the surface preparation processes regarding ∆E1 values. There was no significant difference between the composites and bonding agents in ∆E1 values, except for Cerasmart/Sylc and Empress/Sylc groups. No statistically significant difference was detected in ∆E2 values between the surface preparation treatments in all groups. (p>0.05). Conclusion Color match of the universal shade composites, which are preferred to increase the esthetic satisfaction and to simplify repair procedures, were found above the acceptable threshold. Post-aging color stability of universal shade composites was below the acceptable threshold.
