Spectrophotometric analysis of coronal discoloration in-vitro induced by various bioceramic cement

Abstract

Introduction: Vital pulp therapy procedures (for example, direct or indirect pulp capping and pulpotomy), and even other procedures like perforation repair and regenerative endodontics involve the placement of various types of materials. which could lead to coronal discoloration [1–3]. The main goals in endodontics, besides good clinical practice, is also to provide a better aesthetic result [4]. Therefore, the aim of this study was to evaluate and quantify, in-vitro, coronal discoloration induced by bioceramic materials and their influence during the determinant “time”.

Materials and methods: This work was approved by the IUEM Ethics Committee (Protocol). A total of 44 human monoradicular teeth were divided into four groups (n = 11): G1 - negative control; G2 - filled with MTA ProRoot, G3 - filled with Biodentine and G4 - filled with TotalFill BC RRM Fast Set Putty. After the placement of the bioceramic cement, they were immersed in saline solution during 30 days at 37° C. Color evaluation was obtained with a spectrophotometer (Spectroshade Micro Optic - MHT S.p.A., Arbizzano di Negar, Italia) according to manufacturer’s instructions at 5 incubation periods defined as follows: t0 – before material application and incubation; t1 – just after material application but still before incubation; t24h – after 24h of incubation; t7d – after 7 days of incubation and t30d – after 30 days of incubation. Descriptive and inferential statistical analyses were performed. Cochran’s Q test evaluated coronal discoloration in the different groups, Kruskal Wallis test verified differences in discoloration of experimental groups and finally Friedman test verified variation of discoloration between groups over time. A significance level of 5% was set.

Results: All experimental groups revealed coronal discoloration over time (G1 - (p = 0.001), G2 - (p <0.001), G3 - (p = 0.001) and G4 - (p = 0.006)) which wasn’t statistically significant between groups (p> 0.05). The MTA group in the intervals [t0-t1] and [t24h-t7d] varied most (p = 0.037) comparing to the remaining experimental groups, although all groups presented an identical final discoloration. In the final time interval [t7d-t30d], the TotalFill group presented the highest discoloration (ΔE = 7,29), followed by MTA (ΔE = 6,64), Control (ΔE = 6,40) and Biodentine (ΔE = 5,49). However, this discoloration was not statistically significant (p = 0.779) between groups.

Discussion and conclusions: All materials induced discoloration over time without significant differences compared to the control group. This discoloration was induced by either the presence of blood and the presence of the bioceramic cement [5]. It is therefore important to inform the patient that tooth discoloration may occur as a side-effect compromising the aesthetic outcome.