Effect of Two Bleaching Agent Products on Mercury and Silver Ion Release from Dental Amalgam

Objective: Bleaching of the teeth is considered as a safe, effective, and conservative procedure to treat discolored teeth. The aim of the present study was to compare the amount of mercury and silver released from amalgam after applying two brands of carbamide peroxide 16% bleaching gel. Materials and Methods: For this experimental study, 384 amalgam tablets were prepared. The samples were kept in distilled water for a month and then were randomly classified into three groups (two experimental and one control groups). The experimental groups were placed in two different Carbamid Peroxide 16% gels (Kimia, Iran, and Nite White, USA) and the control group was placed in Phosphate Buffer with pH=6.5. Then the amount of the released mercury and silver ion was determined using AVA-440 analyzer system based on cold-vapor atomic absorption method after 14 and 28 hours. ANOVA and Tukey HSD tests served for statistical analysis. Results: Carbamid proxide 16% gels caused a significant increase in the amount of mercury and silver released from amalgams in experimental groups (P<0.001). The amount of Mercury and silver released from amalgams in Kimia gel was significantly more than Nite White 16% (P<0.001). The mercury release was not time-dependent (P>0.05) but the silver release was (P<0.05). Conclusion: Carbamide peroxide bleaching gels increase mercury and silver release from dental amalgams. The gel brand seems to have a significant influence on the amount of ion released from the dental amalgam.