Effects of 0.2% Chlorhexidine and Re-polishing on the Color Stability of Nanofilled Composite Resins

  The growing demand for esthetic dental procedures has resulted in the increased development of new restorative composite resins. The success of composite resin restorations depends on their color stability over time. The present study aimed to evaluate the effects of 0.2% chlorhexidine (CHX) and
re-polishing on the color stability of nanofilled composite resins. This interventional, in-vitro study was conducted on 48 disk-shaped samples (diameters: 8×2 mm), which were prepared using Z350 (3M ESPE, USA) and Grandio (VOCO, Germany) A2 shade composite resins. The samples were divided into four groups of 12 and immersed in CHX and distilled water for 14 days. Colorimetry of the samples was performed before and after immersion in the solutions and after re-polishing using a spectrophotometer. Data analysis was performed using the analysis of variance (ANOVA) and Tukey’s test at the significance level of α=0.05. All the composite resin samples exhibited discoloration (ΔE1<3.3), and a significant difference was observed in discoloration with CHX between the two composite resins (P<0.05), with greater discoloration in the Grandio composite resin (ΔE1=2.041). In addition, the color changes of the samples were considered significant between water
and CHX (P<0.05), and a distinct color change was denoted in the samples after re-polishing. According to the results, the color changes in the composite resins were a function of the type of the composite resin and solution used for immersion