Physicochemical properties of gutta-percha cones before and after a rapid disinfection protocol and its clinical relevance

This study aimed to evaluate the chemical composition, radiopacity, and antimicrobial activity of five standardized (#25) commercially available gutta-percha points (ProTaper Gold, Zarc, Cerkamed, Autofit, and Reciproc R25), before and after a rapid disinfection protocol. The cones were divided into three groups: untreated (control), treated with sodium hypochlorite, and treated with sodium hypochlorite followed by ethanol rinsing. Significant compositional differences, as assessed by a solvent extraction method, were observed among brands, with gutta-percha content ranging from 11.6 to 17.5%, wax and/or resin from 1.2 to 4%, and inorganic fraction between 74.0 and 83.0%, with ZnO as the predominant component. Radiopacity determined via digital radiography varied among brands and showed a stronger correlation with ZnO content than with BaSO₄, challenging the common assumption that barium is the principal radiopacifying agent; Zarc exhibited the highest radiopacity, whereas Cerkamed showed the lowest. None of the gutta-percha points exhibited antimicrobial activity against Enterococcus faecalis and Staphylococcus aureus under standard clinical conditions, underscoring the necessity of proper disinfection procedures in clinical practice. The disinfection protocols produced minor changes in the wax/resin content of Cerkamed, Reciproc, Autofit, and ProTaper, with the effect being more pronounced in the latter two. In contrast, the metal oxide composition analyzis with wavelength dispersive X-ray fluorescence (WDXRF), showed that only Zark exhibits slight variations in ZnO, BaSO₄, SiO₂, and CuO. However, these changes remain insufficient to be considered clinically relevant. Importantly, no effect on the radiographic integrity of the gutta-percha cones was observed, confirming the safety and adequacy of the NaOCl-based disinfection protocols for clinical purposes.