Effect of External Bleaching on Color Change of Single Shade Resin Composite Versus Nano-Filled Resin Composite in Class V: In Vitro Study

Aim: This study investigated the effect of bleaching on color change of the single shade universal composite (Omnichroma) versus nano-filled resin composite (Z350 XT). Materials and Methods: Twenty premolars of shade A3 were used for the study. Standardized class V cavities were prepared on the cervical third of the buccal surface of all teeth. After that, teeth were randomly divided into two groups of 10 teeth each according to the type of resin composite used. After composite application, all teeth were stored individually in distilled water for 24 hours. Evaluation of the restoration color was done using VITA Easyshade. The teeth were bleached and stored again for another 24 hours. Re-evaluation of the restoration color was done at 24 hours, one week and one month after bleaching. Results: There was no statistically significant difference between the two restorative materials at 24 hours and after one week. While there was a statistically significant difference between the two restorative materials after one month. Conclusion: Omnichroma single shade universal restorative material demonstrates structural color change post-bleaching procedure