Biocompatibility analysis in subcutaneous tissue and physico-chemical analysis of pre-mixed calcium silicate–based sealers

Abstract

To evaluate the biocompatibility, physical and chemical properties of three pre-mixed calcium silicate-based sealers and an epoxy resin-based material were assessed. Pre-mixed sealers supposedly obtain water from the root canal moist to hydrate and set. Polyethylene tubes were filled with the materials Bio-C Sealer Ion+, Bio-C Sealer, EndoSequence BC Sealer and AH Plus Jet, or left empty and surgically implanted in the subcutaneous tissue of Wistar rats. The animals were euthanised and the tubes and tissue were removed for histological analysis and scanning electron microscopy (SEM) coupled with energy-dispersive spectrometry (EDS). Materials' surface chemical characterisation was assessed using Raman spectroscopy and SEM/EDS. Flow, setting time (in two conditions), solubility, radiopacity and pH were also analysed. ANOVA and Bonferroni correction were performed for comparisons (P < 0.05). Inflammatory response observed in the tissues subsided from 7 to 30 days. Tungsten migration could be detected in the surrounding tissue following AH Plus Jet implantation. All calcium silicate-based sealers exhibited zirconium oxide (radiopacifier) and tricalcium silicate peaks before and after implantation. All materials exhibited flow values above 17 mm. An approximately tenfold difference was observed between the plaster- and metal-mould setting times of the calcium silicate cements indicating its sensitivity to moist variations and solubility above 8% was also observed for these materials. Pre-mixed materials exhibited variable setting time and solubility with a decreasing inflammatory response. The variable moist-dependant setting time with high solubility poses a concern for the clinical use of these pre-mixed sealers.