Analysis of physicochemical properties of endodontic sealers containing rhodamine B

The use of fluorescent dyes in microscopy studies is frequent. Therefore, it is important to investigate whether these compounds may alter the physicochemical properties of materials in which they are incorporated to avoid methodological biases. This study evaluated the physicochemical properties of two endodontic sealers containing dry or diluted rhodamine B. Six groups were evaluated: AH Plus and MTA Fillapex in their original composition and mixed with 0.1% dry or diluted rhodamine. Push-out test was applied to assess the bond strength to root dentin. ANSI-ADA No. 57 and ISO No. 6876:2012 specifications were followed to evaluate flowability, setting time, and solubility of the sealers. pH changes were assessed after 24 h, 7, and 30 days. Intergroup comparisons were analyzed by ANOVA complemented by Tukey's post-hoc test; comparisons among periods were analyzed by Wilcoxon and Friedman tests. The incorporation of dry rhodamine decreased the bond strength and prolonged the setting time of AH Plus. The incorporation of diluted rhodamine decreased the setting time and increased the flowability of MTA Fillapex. Diluted rhodamine promoted pH reduction of AH Plus after 24 h and dry rhodamine after 7 days. Rhodamine incorporation promoted pH reduction after 30 days for MTA Fillapex. Solubility was not affected. In conclusion, the incorporation of diluted rhodamine changed the properties of MTA Fillapex, and the incorporation of dry rhodamine changed the properties of AH Plus. Previous dilution of rhodamine did not severely compromise the physicochemical properties of AH Plus and may be suggested to assess its penetrability.