CLINICAL-EVALUATION OF HIGH-COPPER AMALGAMS

Purpose: To compare the clinical performance of two high-copper amalga m alloys with different compositions by evaluating marginal fracture o f each restoration over a 2-year period. Materials and Methods: Restor ations of Valiant PhD and Zenith Premium alloy were placed in Class I and II cavity preparations in patients and evaluated at baseline, 1 an d 2 years to determine their degree of marginal breakdown. Results: Af ter 2 years, the Zenith Premium alloy exhibited significantly less mar ginal breakdown than the Valiant PhD alloy with no significant additio nal deterioration of the Zenith restorations between the 1st and 2nd y ear. The data indicate that the Zenith Premium alloy exhibits less mar ginal deterioration than Valiant PhD so it may be predicted that it wi ll perform better long term. A possible explanation for this better pe rformance may be that the Zenith Premium contains zinc while the Valia nt PhD includes palladium but no zinc in its formulation.