OR08 - Mechanical Agitation Effects on Physical Properties of Calcium-Silicate-Cement Sealers

Abstract: Endodontic sealers are crucial to achieving a fluid-tight seal within the intricacies of root canal systems. While these sealers have been available in hand-mixed or syringe-mixed formulations, there is now a surge in pre-mixed calcium-silicate-cement (bioceramic) sealers. Requirements for sealers are listed in ISO-6876:2012. This study investigated real-time setting reactions and the effects of mechanical agitation on flow, film thickness, and setting time of a calcium-silicate-cement sealer (EndoSequence Bioceramic sealer). A single-paste bioceramic sealer (Brasseler, USA) was agitated for 10 seconds using a vortex mixer to assess flow, film thickness, and setting time (n=10) before and after agitation in accordance with ISO 6876:2012 methodology. All samples were stored in a 37°C and 100% humidity incubator. A Gilmore indenter was used to establish the initial and final setting times. For real-time setting reaction assessment, a ReactIR FTIR (Mettler Toledo) spectrometer probe was employed to collect data for a 24-hour period. Data analysis was performed using the Student’s t-Test. For the experimental-agitation and control groups, respectively, the mean flow was 18 (±3) mm and 19 (±2) mm, film thicknesses were 42 (±7) µm and 55 (±14) µm, and initial/final setting times were 136 (±39)/653 (±12) and 570 (±41)/930 (±32) minutes. FTIR data showed stabilization of the hydration reaction after 2 hours. Mechanical agitation has an influence on the flow, film thickness, and setting time of bioceramic sealers and should be considered prior to clinical use as it results in less tendency for phase separation and tackiness. More studies are needed to evaluate the complex hydration reaction promoting gelation in pre-mixed single-paste calcium-silicate-cement sealers.