Influence of various class cleaning agents for prosthesis on Co–Cr alloy surface

Abstract

Abstract Introduction Denture cleaners should not be harmful to dental prostheses elements, but immersions in cleaner solutions during a long time of using prosthesis may cause changes on Co–Cr alloy surfaces. There are five classes of denture cleaners: alkaline hypochlorites, alkaline peroxides, disinfectants, diluted acids, and enzymes. The aim of this work was to evaluate the influence of denture cleaners solutions on the surface properties of Co–Cr alloy. Materials and method Specimens cast from cobalt–chromium alloy were divided into eight groups: 1 – dry; 2 – ultrapure water; 3 – 20% wt/wt sodium; 4 – 20% chlorhexidine digluconate; 5 – Correga Tabs BioFormula; 6 – 20% wt/wt citric acid; 7 – 0.5% NaOCl; and 8 – 5.0% NaOCl. After immersion in 200 mL of cleaning agent solution at 45°C in 3 years, simulation of use, surface roughness, contact angle, surface free energy (SFE), and microscopic observation was performed. Results For citric acid and NaOCl, roughness (R a) raised clearly. These cleaning agents also caused R q, R v, R p, and R Sm to increase the most. The observed water contact angle after using denture cleaners, especially citric acid, and NaOCl decreases, and the values of SFE increase. Under a digital microscope, the harmful effect of citric acid and solutions of NaOCl was visible. Conclusions Diluted acids and alkaline hypochlorites in presented concentrations influence Co–Cr surface parameters like roughness and wettability. Other classes of denture cleaning agents do not affect surface roughness parameters which make them safer for the metallic components of removable partial dentures.