RESUMEN
Element release from dental casting alloys into the oral environment is of clinical concern and is considered to be a potential health problem to all patients. The aim of this study was to investigate the metallic ion release of four base metal alloys. Two Ni-Cr [Minalux and Supercast] and two Co-Cr alloys [Minalia and Wironit] were examined. Nine specimens of each type were prepared in 13×11×1.4 mm dimensions and each of the four alloys [3 specimens per group] were conditioned in artificial saliva at 37 c for one, three and seven days. The conditioning media were analyzed for element-release using Inductive Coupled Plasma Atomic Emission Spectrophotometer [ICPAES]. Collected data were statistically analyzed using ANOVA and Duncan multiple range test [P< 0.05]. The greatest amount of element release was seen after seven days [134.9 ppb Supercast, 159.2 ppb Minalux, 197.2 ppb Minalia, and 230.2 ppb Wironit]. There was a significant difference between the released elements from the alloys after the three conditioning times [p<0.001]. Element release from the studied alloys is proportional to the conditioning time. The Ni-Cr alloys tested in this investigation were more resistant to corrosion as compared to the Co-Cr alloys in artificial saliva. Supercast had the highest corrosion resistance
RESUMEN
One of the greatest problems in metal -ceramic restorations is debonding of porcelain from dental alloys. Production of dental alloys by Iranian companies necessitates the evaluation of physical and handling properties of these products. In this study the bond strength between porcelain and two types of base metal alloys, Supercast [with beryllium] and Minalux [without beryllium] was investigated. In this experimental study 10 cylindric bars from each base metal alloy were prepared. The bars were degassed and porcelain was applied around them in a disc form [8 mm diameter and 2 mm thickness]. The bond strength of porcelain to metal bars was tested with the shear strength test by Instron. Data were analyzed with student t-test and P<0.05 was considered as the limit of significance. The mean failure load was 71.58 +/- 6.4 KgF for Supercast and 67.34 +/- 5.48 for Minalux alloy. The bond strength of Supercast and Minalux were 55.85 +/- 4.99 MPa and 52.54 +/- 4.27 MPa respectively. The difference was statistically significant [P<0.001]. This study showed that nickel-chromium-beryllium alloy [Supercast] produced significantly better ceramometal bonding than nickel chromium alloy without beryllium [Minalux]