(PR010) Dissimilarities in Currently Marketed Calcium Silicate-Based Sealers

Objective: This study investigated the physicochemical properties of calcium silicate-based sealers—BioRoot Flow, NeoSEALER Flo, TotalFill BC Sealer, and BC Universal Sealer—focusing on their reactivity over time (pH and calcium ion release), and elemental composition.

Methods: Triplicate samples were immersed in 10 ml phosphate-buffered saline (PBS) for 1 hour, 1- , 7-, and 28 days, then transferred to 5 ml of Millipore water for 30 min. Release of H⁺ and Ca²⁺ were thus quantified using a calibrated pH meter and atomic absorption spectroscopy (AAS), respectively. Scanning electron microscopy (SEM) was used to identify apparent CaP precipitates on samples immersed in PBS for 28 days, and elemental analysis was conducted using energy-dispersive X-ray spectroscopy (EDS).

Results: All sealers maintained an alkaline pH with minor fluctuations. Their peak calcium release occurred after 1 h of PBS immersion, with a gradual decrease over time. BioRoot Flow and TotalFill BC Sealer demonstrated the highest pH values and calcium release. EDS analysis revealed that, next to Ca, Si, and O, BioRoot RCS contained Zr; NeoSEALER Flo Ta and Al; TotalFill BC Zr and P, and BC Universal Sealer Zr, Al, and Ti. SEM images revealed calcium phosphate precipitation on the surface of all sealers. The sealers based on pure calcium silicate (absence of Al) showed a more consistent Ca release than their Portland cement-based counterparts.

Conclusions: The study highlights differences in the reactivity of currently marketed calcium silicate-based sealers, which appear to be rooted in their differing elemental compositions. These differences can be explained by their cement as well as their radiopacifier components.