Tooth discolouration analysis induced by two Calcium Silicate-based Materials: in vitro study

Abstract

Aim: to evaluate the over time chromatic alterations/discolouration in tooth crowns induced by two Calcium silicate based-materials (CSMs) - White mineral trioxide aggregate (WMTA- ProRoot® MTA) and BiodentineTM - used to fill pulp chambers. Materials and Methods: Twenty-eight premolar human teeth were sectioned 2 mm below cemento-enamel junction (CEJ). Pulp tissues were extirpated through the cervical cut, and occlusal standardized cavities were prepared. The specimens were split according to a stratified random sampling by value into four groups: Group 1- Negative control (filled with dry sterile cotton pellets) (n=4); Group 2- Positive control (filled with blood moistened sterile cotton pellets) (n=4); Group 3- WMTA (ProRoot® MTA) (n=10); Group 4- Biodentine™ (n=10). Colour measurements were recorded with Colorimeter (PR®-650 SpectraScan® Colorimeter, Topanga Canyon Place Chatsworth, CA) at 3 time points: T0, baseline; T1, immediately after material placement, and T2, 6 weeks after. The measurements were taken under standardized conditions: dark room and a white cardboard box illuminated with a LED light of 5500k and 6 watts. Data were transformed into values of the CIE L*a*b* colour system, and the corresponding colour differences (ΔE) values were calculated. Between the measurements the specimens were stored in tap water, in the dark, in a 100% humidity environment at 37°C, with normal atmospheric gas levels. The results were analysed using repeated ANOVA measurements, unilateral t-Student test considering a cut point of 2.3, mixed ANOVA procedures, Kruskal-Wallis test, Mann- Whitney test, and one-way ANOVA with Tukey post-hoc tests. The significance level was set at α<0.05. Results: There were not found statistically significant differences in colour alteration (ΔE) between the two CMSs (group 3-WMTA and 4-Biodentine™), for all time intervals. Relative to L* parameter, it is possible to observe statistically significant differences, between WMTA and Biodentine™. Conclusion: Concerning global colour variation (ΔE), there was no significant difference between the two CMSs (WMTA and Biodentine™), for all time intervals, over time. However, relative to L* parameter, it was possible to observe statistically significant differences, between WMTA and Biodentine™, being the L* variation for WMTA higher, indicating a greater tooth discolouration in terms of value.