Future Dental Journal of Egypt


Objective: To investigate effect of 15% carbamide peroxide bleaching gel on color of Class V resin composite restoration. Materials and methods: 60 class V cavities were made in maxillary premolars Teeth were randomly divided into four groups of 15 specimens each (2 control and 2 experimental or bleached groups). Group A to be restored with light nanocomposite resin (Filtek Z350 XT) with no post-restoration bleaching procedure (control). Group B to be restored with light nanocomposite resin (Filtek Z350 XT, with post-restoration bleaching procedure (Experimental). Group C to be restored with microhybrid resin (Filtek 250 XT) with no post-restoration bleaching procedure (control). Group D to be restored with microhybrid resin (Filtek 250 XT), with post-restoration bleaching procedure (Experimental). The bleaching was made with 15% at home bleaching agent (Opalescence PF). Color, opacity and fluorescence were analyzed by taking digital photos for the specimens at baseline and 24 h after completion of the bleaching procedure. The color pattern was evaluated according to the CIE - L*, a* and b* color system. Bleaching according to the following equation (25) ΔE=[(ΔL) 2+(Δa) 2+(Δb) 2] 1/2 For optical analysis, the specimens were subjected to the color measurements on white and black patterns, considering only the L* coordinate, which was calculated according to the formula: Opacity = L*b/L*w, where L*b corresponds to the reading of the L* coordinate against a black background and L*w against a white background. This procedure was performed before after bleaching, and the difference in opacity between the two periods was calculated in percentage. While for fluorescence comparison, the Fluorescence parameter (FL) was calculated, at baseline and post bleaching procedure, as the difference in color (ΔE) depending on the inclusion or exclusion of the UV component according to the equation: FL = [(CIE L*100 – CIE L*0) 2 + (CIE a*100 – CIE a*0) 2 + (CIE b*100 – CIE b*0) 2] 1/2, where subscripts 100 and 0 denote the 100% UV-included and the UV-excluded conditions respectively. The recorded data for the tested materials' color, opacity and fluorescence were collected and statically analyzed with IBM® SPSS® statistical version 20 with the significance level set at P≤0.05. Results: There was no statistically significantly different between the two materials before as well as after bleaching. Conclusion: the color change of the nanofilled and microhybride light activated composite after bleaching (home-bleaching) was not perceptible or significant.