Spectrophotometric analysis of coronal discolouration induced by grey and white MTA

Aim To evaluate the specific alterations in tooth colour with white and grey MTA when used to fill pulp chambers. Methodology Forty-five fully developed, intact, mandibular third molars were sectioned 1 mm below their cemento-enamel junction (CEJ). Their pulp chambers were chemo-mechanically debrided, and the specimens were randomly assigned into three groups: Group 1–white MTA (Angelus™), Group 2–grey MTA (Angelus™) and Group 3–negative control (unfilled). During the experimental period, specimens were immersed in vials containing distilled water up to the CEJ (37±1 °C). Spectral reflectance lines were recorded by utilizing a UV–vis spectrophotometer equipped with an integration sphere in the visual spectrum, at baseline, 1 week and 1, 2 and 3 months after placement of the materials. Data were transformed into values of the CIE L*a*b* colour system, and the corresponding ΔE values were calculated. The results were analysed using two-way mixed anova models, whilst pairwise comparisons were conducted with Bonferroni's method at P