Cytotoxicity of precious and nonprecious alloys—experimental comparison of in vitro data from two laboratories

Abstract

The aim of this investigation was to evaluate and compare the reproducibility of cytotoxicity data generated in two different laboratories using the same testing protocols. A series of dental alloys that are widely used in both countries were chosen. These alloys (five precious, two nonprecious) were wet ground up to 1200 grit SiC, sterilized in 70% ethanol, and extracted in sterile culture medium for 7 days. Pure copper was used as a positive control and Teflonreg and media only were used as negative controls. Test and control samples were randomized and blinded to each laboratory. Cells, primary human gingival fibroblasts, and immortalized 3T3 fibroblasts, were exposed to the extracts for 24 h. Extract cytotoxicity was evaluated spectrophotometrically with the use of a mitochondrial enzyme activity assay. Data were collected from both laboratories, combined, and subjected to a mixed-model analysis of variance. No statistical difference was obtained for the immortalized 3T3 cells, except for two extracts in which differences between the two labs were significant but were still not cytotoxic. Furthermore, no statistical differences were found for the primary cells. These data strongly suggest that cytotoxicity tests performed in different laboratories with the use of the same test materials may lead to comparable results if sample preparation, cells, test procedures, and data analyses are carefully considered.

The effect of recasting on biological properties of Ni-Cr dental alloy

“…In this research, the cytotoxicity of a Ni-Cr dental alloy was tested. Reference data indicate the disagreement in attitudes among different authors concerning the issue of possible repeated casting of these alloys [12][13][14][15][16][17]. Knowing the procedure of fabrication of dental restorations, the question which arises is whether the use of previous casting residues is harmful.…”

Synergistic cytotoxic effects of ions released by zinc–aluminum bronze and the metallic salts on osteoblastic cells

“…Cellular interactions with metal ions show differences in rates of uptake,7 in concentrations levels which affect cell response, and in the cellular functions affected 8–12. Different sources of ions have been used in cytotoxic studies: (a) the extracts obtained from the dissolution of a metallic sample ex situ and then added to the cell culture;13–15 (b) the dissolution of metal samples in situ ;16–21 and (c) the metal salts added to the cell culture 22–28. Data of the amount of metal ions released by several dental casting alloys were obtained in different assays 13.…”

Mechanical Properties of Co-Cr Alloys for Metal Base Framework

“…Anticorrosive depends on surface chrome oxide passive film. [9][10][11][12][13] The occlusal load can get as high as 900 N in molar region. Prostheses undergo to the cyclic dynamic and static loading, which results in stress concentration.…”