Efeito de soluções higienizadoras em ligas metálicas de cobalto-cromo para próteses dentárias: uma revisão sistemática de estudos in vitro

Abstract

The use of sanitizing chemical solutions represents an important alternative to complement the mechanical cleaning of dental prostheses, contributing to the maintenance of patient's health and longevity of prosthetic devices. However, these products can generate deleterious effects on prosthetic materials (acrylic resin for denture base and artificial teeth, metallic alloys) such as changes in surface roughness and color, ion release, corrosion, toxicity, among others. There is no consensus in the literature regarding the most adequate chemical products for the cleaning of dental prostheses containing metallic alloys. Objective: This systematic review of the literature evaluated the effects of chemical solutions commonly used in the control of denture biofilm on the properties of cobalt- chromium (Co-Cr) metallic alloys. Methods: A bibliographic research was conducted in August 2020 in Medline/Pubmed, Scopus, Web of Science, Virtual Health Library (BVS), Embase and Open Grey databases. In vitro studies were included, without language and period restrictions, which tested the effect of sanitizing solutions in Co-Cr metal alloys. Data regarding the type of alloy, sample size, tested sanitizing solutions, control groups, use regimes, simulated time of the analyses, types and periods of the evaluations performed, and main results were extracted. Results: Initially 2137 articles were identified, from which after removal of duplicates and excluded studies based on eligibility criteria, 9 articles were selected and included in this review. The sanitizing solutions evaluated were peroxides and alkaline hypochlorites, diluted acids, disinfecting agents and enzymes. Variations in mass, surface roughness, bending strength, color and chemical composition parameters, as well as presence of staining, ion release and corrosion were evaluated in periods ranging from 7 days of immersion to 5 simulated years. In general, the effects of alkaline peroxides on the properties of alloys show greater variation depending on the brand and type of alloy. Hypochlorites and citric acid solutions were responsible for the major changes in relation to corrosion, ion release, weight loss, reduced reflectance, and flexural properties. Enzymes and mouthrinses containing chlorhexidine digluconate and cetylpyridinium chloride conferred few changes in Co-Cr alloys. Conclusions: Given the methodological variability between the studies, oral rinses containing chlorhexidine and cetylpyridinium chloride, enzymes, as well as solutions containing acetic and peracetic acids, may be indicated in the sanitization of dental prostheses containing metal parts of Co-Cr. Some brands of alkaline peroxides may also be used, however, the indication, frequency and regimen of use of these products should be carried out with caution, based on accurate information from professionals to patients. Alkaline hypochlorite and citric acid solutions should be avoided due to their higher corrosion power.