Corrosion kinetics and topography analysis of Ti–6Al–4V alloy subjected to different mouthwash solutions

This study evaluated the corrosion kinetics and surface topography of Ti–6Al–4V alloy exposed to mouthwash solutions (0.12% chlorhexidine digluconate, 0.053% cetylpyridinium chloride and 3% hydrogen peroxide) compared to artificial saliva (pH 6.5) (control). Twenty Ti–6Al–4V alloy disks were used and divided into 4 groups (n = 5). For the electrochemical assay, standard tests as open circuit potential and electrochemical impedance spectroscopy (EIS) were applied at baseline, 7 and 14 days after immersion in the solutions. Scanning electron microscopy, atomic force microscopy and profilometry (average roughness — Ra) were used for surface characterization. Total weight loss of disks was calculated. Data were analyzed by ANOVA and Bonferroniʹs test (α = 0.05). Hydrogen peroxide generated the lowest polarization resistance (Rp) values for all periods (P < 0.05). For the capacitance (Cdl), similar results were observed among groups at baseline (P = 0.098). For the 7 and 14-day periods, hydrogen peroxide promoted the highest Cdl values (P < 0.0001). Hydrogen peroxide promoted expressive superficial changes and greater Ra values than the others (P < 0.0001). It could be concluded that solutions containing cetylpyridinium chloride and chlorhexidine digluconate might be the mouthwashes of choice during the post-operatory period of dental implants. However, hydrogen peroxide is counter-indicated in these situations. Further studies evaluating the dynamics of these solutions (tribocorrosion) and immersing the disks in daily cycles (two or three times a day) to mimic a clinical situation closest to the application of mouthwashes in the oral cavity are warranted to prove our results.