Effects of chemical composition on the corrosion of dental alloys

Abstract

The aim of this study was to determine the effect of the oral environment on the corrosion of dental alloys with different compositions, using electrochemical methods. The corrosion rates were obtained from the current-potential curves and electrochemical impedance spectroscopy (EIS). The effect of artificial saliva on the corrosion of dental alloys was dependent on alloy composition. Dissolution of the ions occurred in all tested dental alloys and the results were strongly dependent on the general alloy composition. Regarding the alloys containing nickel, the Ni-Cr and Ni-Cr-Ti alloys released 0.62 mg/L of Ni on average, while the Co-Cr dental alloy released ions between 0.01 and 0.03 mg/L of Co and Cr, respectively.The open-circuit potential stabilized at a higher level with lower deviation (standard deviation: Ni-Cr-6Ti = 32 mV/SCE and Co-Cr = 54 mV/SCE). The potenciodynamic curves of the dental alloys showed that the Ni-based dental alloy with >70 wt% of Ni had a similar curve and the Co-Cr dental alloy showed a low current density and hence a high resistance to corrosion compared with the Ni-based dental alloys. Some changes in microstructure were observed and this fact influenced the corrosion behavior for the alloys. The lower corrosion resistance also led to greater release of nickel ions to the medium. The quantity of Co ions released from the Co-Cr-Mo alloy was relatively small in the solutions. In addition, the quantity of Cr ions released into the artificial saliva from the Co-Cr alloy was lower than Cr release from the Ni-based dental alloys.

Corrosion resistance assessment of Co-Cr alloy frameworks fabricated by CAD/CAM milling, laser sintering, and casting methods

“…Several studies have previously investigated corrosion and electrochemical characteristics of cast Co-Cr alloys. 8,26,[28][29][30][31][32][33][34][35] However, only a few studies evaluating corrosion resistance and electrochemical properties of the alloys produced by conventional casting, milling, and laser sintering methods have been reported. 36,37 The purpose of the present study was to evaluate electrochemical corrosion resistance of Co-Cr specimens produced by casting, CAD/CAM milling, and DMLS methods in a medium simulating the oral environment.…”

Effect of fluoride sodium mouthwash solutions on cpTI: evaluation of physicochemical properties

“…The edge of the sample area was defined by pressing a sample against an o'ring and exposing an area of 3.64 cm 2 . Potentials were measured against a standard calomel electrode-SCE (B20B110; Radiometer Analytical) and a platinum plate served as the counter electrode, with an exposure area of 1 cm 2 (wire B35M110; Radiometer Analytical) (17). Before testing, the specimens were ultrasonically cleaned (Ultrasound 1440 D Medical; Dental Equipment Trade Ltda, Ribeirão Preto, SP, Brazil) in ethanol for 10 min and in distilled water for 10 min.…”

“…Afterwards, the potentiodynamic polarization curves were drawn from -500 mV to +2,000 mV vs SCE with a scanning rate of 2 mV/s; all the tests were carried out at 37 ± 1°C. The test was repeated at least 5 times per condition (17).…”

Investigations on Dental Alloys Using Metallographic Observation, Scanning Electron Microscopy, and Energy- Dispersive X-Ray Spectroscopy

“…Alloy-related internal factors include composition, structure, impurities, and surface condition, and the external factors being electrolyte related (composition, concentration, temperature, oxygen content, pH, heterogeneity, etc.) [8]. Parameters related to topography (surface ratio of the two materials, geometric distribution, etc.)…”