Tooth discoloration induced by calcium-silicate-based pulp-capping materials

Objectives: The aim of this study was to evaluate tooth discoloration induced by contact with various calcium silicate-based pulp capping materials in the presence or absence of blood in vitro. Materials and Methods: Eighty bovine samples were divided into six experimental groups and two control groups according to the type of material used (ProRoot [PR], Endocem [EC], or EndocemZr [ECZ]) and the presence or absence of contamination with blood. A spectrophotometer was used to calculate the color difference (ΔE) between the baseline measurement (after placement of materials) and measurements taken 1, 2, 4, and 8 weeks. The results were analyzed with repeated measures analysis of variance, Tukey's post-hoc tests and independent t-tests (P = 0.05). Results: The PR group and EC group showed significantly higher mean values of ΔE than the negative control group after 2 weeks (P < 0.05), whereas ECZ did not. There were larger ΔE values when there was contact with blood, especially in PR and EC group (P < 0.05). Conclusions: ECZ which contains zirconium oxide as a radiopacifier showed less discoloration irrespective of blood contamination compared to PR and EC.