Evaluation of color stability of different repairing materials

Evaluate the potential for dental color alteration of high-plasticity cements, MTA HP and MTA Flow, in comparison with MTA Angelus with calcium tungstate as radiopacifier; and alternative the formulations proposed, MTA Flow + 5% zinc oxide (ZnO) and an Experimental cement (powder of tricalcium silicate, bismuth oxide, ZnO and liquid of distilled water and water-soluble polymer). Thirty-five bovine teeth were prepared and filled with the cements (n=5). Triple antibiotic paste and unfilled samples were the positive and negative controls, respectively. The specimens were immersed in water and the color assessed with a spectrophotometer: before filling (B), 24 hours (24h), 28 days (28d) and 90 days after filling. The color change (ΔE) and the luminosity (*L) were calculated. The statistical analysis was performed using nonparametric Kruskal-Wallis and Dunn test (p < 0.05). The analysis of delta E values showed that all the materials presented color alteration after the evaluated periods. High *L values were found for MTA HP and Experimental, with statistical difference in relation to MTA Flow at 90d (p > 0.05). The addition of ZnO inhibited dental staining of MTA Flow after 90d of contact with dentine. The MTA Flow presented potential for dental discoloration, which is inhibited by the addition of zinc oxide. The experimental cement presented similar luminosity values than that presented by MTA and MTA HP.