Effect of Home Bleaching on the Color Matching of Composite Resin Restorations

Objective: To investigate the effect of home bleaching on color matching between the dental restoration and the adjacent tooth structure after the staining process. Material and Methods: Ten intact maxillary central incisors were used. After preparation (semimesial restoration of the specimens), the specimens were immersed in a colored solution for 14 days and then were washed and the bleaching process was there after performed. A spectrophotometer apparatus was used to determine the color of the specimens in the part of the tooth filled with restorative material three times, including before the staining process, fourteen days after the staining process and immediately after the bleaching process. Paired t-test was employed to compare the color of the intact tooth and the dental restoration before and after the staining and bleaching processes. The level of significance was set at 5%. Results: Pre-bleaching E color of the teeth was 68.1, which increased to 78.8% after bleaching, and this increase was also statistically significant (p<0.001). Pre and Post-bleaching E color of composite restorations was 65% and 77.6%, respectively. This increase was also statistically significant (p<0.001). Postbleaching E color of the tooth and composite material was 78.8% and 77.6%, respectively. This difference was not statistically significant (p=0.342). Conclusion: The staining and bleaching processes had a significant effect on the discoloration of the dental restoration and the tooth; however, the application of bleaching on the teeth and composite improved the tooth composite color-match.

Evaluation of the Color Matching of Composite Resin Restoration used for Repair with Initial Composite Resin Restoration

Objective: To investigate the color matching of the composite resin used for repaired with initial composite resin restoration after the aging process. Material and Methods: After preparation of 30 composite resin samples, their color were determined using the spectrophotometer four times and the average was recorded. After the initial aging, the color of the samples was measured again. Then, the repair process was performed with an appropriate composite resin color for each sample and the aging process was performed again. After the second aging, the color of the initial and the repaired composite resins were measured. Then, the data were analyzed by paired T-test. The level of significance was set at 5%. Results: The color difference of the initial composite resin between before and after initial aging, as well as the color difference of repaired composite resins between before and after second aging, were significant (p<0.001). Also, after the second aging, the color difference between initial and repaired composite resin restoration were significant (p<0.001). Conclusion: The color matching of the repaired composite resin with the initial one is not acceptable. In this way, replacement of initial composite suggested instead of repaired.