Mercury release of amalgams with various silver contents after exposure to 15% carbamide peroxide

Background and aim(s): Since it is possible for carbamide peroxide (CP) bleaching agent to contact with amalgam restorations in the oral cavity, the present in vitro study evaluated the amount of dissolved mercury released from amalgam restorations with various percentages of silver content subsequent to the use of 15% CP. Materials and methods: Thirty ANA 2000 amalgam disks with 43.1% silver content and thirty ANA 70 amalgam disks with 69.3% silver content were prepared. In each group, 15 samples were randomly placed in glass tubes containing 15% CP and the remaining 15 samples were placed in buffered phosphate solution (the controls) with the same 3-mL volume of the solution for 48 hours. Subsequently, the amount of mercury dissolved in each test tube was measured using Mercury Analyzing System (Cold Vapor Atomic Absorption, MASLO, Shimadzu, Japan). Data was analyzed with two-way ANOVA and a post hoc Tukey test. (I±=0.05) Results: The amount of mercury released under the influence of CP was significantly higher than that released under the influence of buffered phosphate (P<0.001). In addition, the amount of mercury released from dental amalgam with a silver content of 43% was significantly higher than that released from dental amalgam with a silver content of 69% (P<0.001). Conclusion(s): The amount of mercury release is inversely proportional to the silver content of dental amalgam.