CONICET | Buscador de Institutos y Recursos Humanos

For over 25 years copper-based alloys have been used in different countries to make fixed prostheses. Currently, its use is not recommended but is still employed in certain geographic regions for different reasons. These alloys, when in contact with saliva, corrode and release metal ions responsible for the adverse effects reported in the tissue close to the biomaterial. Surface treatments and protective covers are among the most important methods employed for corrosion protection. In this regard, only few studies of the effect of corrosion inhibitors for dental alloys in the presence of mammalian cells have been reported. Objectives: a) to assess the possible inhibitory effect of oral antiseptic on the corrosion of a copper base alloy, b) to compare the cytotoxic effect of the alloy with and without pretreatment with the inhibitor. Materials and Methods: the inhibitory capacity of the chlorhexidine- xylitol-based mouthwash (Periodent) on Orcast PLUS alloy (Cu: 81.5%, Al: 7%, Ni: 4.5%, Fe: 3%, Mn: 2% y Zn: 2%) was evaluated electrochemically by cyclic voltammetry. The pretreatment time of the alloy with the potential inhibitor was 2 h. The effect of the presence of the alloy on the osteoblastic cell line UMR-106 was analyzed using the viability assay based in acridine orange dye. Results: the electrochemical technique showed that pretreatment with antiseptic markedly decreases the corrosion of the alloy with respect to the control for applied potentials more anodic than - 230 mV, reaching an efficiency close to 80%. The assays with the metal in situ revealed a higher percentage of dead cells in the vicinity (closer than 4mm) of the untreated alloy than the percentage obtained with the pretreated alloy (p<0.001). Conclusion: the mouthwash under study is potentially useful as a corrosion inhibitor for the copper base alloy tested.