Özlem Korkut

Potentiodynamic polarisation technique for corrosion testing of Cr–Co and Cr–Ni alloys in artificial saliva and soft drinks

Abstract The corrosion of alloys used in dentistry affects the biological, functional and esthetic properties of the material. This study compares the corrosion behaviour of Cr–Co and Cr–Ni alloys used in restorative dentistry in four different types of solution (distilled water, orange nectar, cola and artificial saliva). Electrochemical polarisation experiments were performed using a potentiostat and carried out in a corrosion cell containing a solution of 500 mL at body temperature (37°C). It can be seen from experimental results that Cr–Co alloy has lower corrosion current densities than Cr–Ni alloy. When the media effect is observed, corrosion current densities are higher for cola and orange juice, which have lower pH. As a result, Cr–Co alloys seem to be, from the biocompatibility point of view, more convenient in the intraoral use as dental alloys. In conclusion, corrosive potential of Cr–Ni alloy is statistically higher in cola drinks compared with juices.

Comparison of dosimetry gels prepared by agar and bovine gelatine

Gel dosimeters are unique materials capable of showing three dimensional (3D) dose distributions of therapeutic or diagnostic exposures. Fricke gel dosimeters can be considered as chemical dosimeters that rely on a radiation-induced chemical reaction. Dose distribution of Fricke solutions containing Fe+2 ions determines the transformation of acidic, oxygen saturated Fe+2 ions to Fe+3 ions by the ionizing radiation in aqueous solutions. In this study we produced two different types of gel dosimeters using agar and bovine gelatin with similar fabrication methods. We compared the magnetic resonance (MR) T1 imaging responses of these two gel dosimeters to acquire a dose dependency of MR intensities. In conclusion agar gel dosimeters found to be produced easily and more consistent.