Clinical Implications for Setting Time Variations in Calcium Silicate Cement Sealers

Objectives: The setting reaction of root canal sealers based on calcium-silicate cement (CSC) starts with hydration which leads to gelation and hardening/strengthening. Setting of CSC sealers range from minutes to several hours depending on the test method and material used. This research compared variations between two test sites for setting time of EndoSequence Bioceramic Sealer (ES-BCS), CeraSeal Bio-Ceramic (CSBC), AH-Plus Bioceramic (AH-BCS) and AH-Plus (control).
Methods: Sealer materials were dispensed into disc-shaped moulds (internal diam. 10mm, height 1mm). Setting times were measured according to the method of ISO 6876:2012 Dentistry-Root canal sealing materials. Using a Gillmore-needle apparatus indenter (Humboldt Mfg Co), initial and final setting were recorded as the times at which no indentation was observed using the two indenters. All testing was performed in an incubator at 37°C and 100% humidity. Elapsed time was measured using a digital timer (Fisher Scientific) at two sites; values were analyzed by descriptive statistics and Student’s t-tests (P<0.05) with Bonferroni adjustment.
Results: All sealers had an initial and final set. The final set required as much as 2 days. However, the variation was as large as 40% between the CSCs (P<.001) while similar variations (10 %) were noted for the control, an epoxy resin sealer.
Conclusions: Variability in data between two test centers could be attributed to agreement on the absence of the indentation, although frequency of checking, differences in the incubators contribute Additionally, sample dispensing method along with dimensions and type moulds used could attribute to the variations. Real-time setting reaction measurement along with cyclic mechanical testing with micro-compression machine could provide more insights about various stages of gelation and strengthening/hardening during setting of CSC sealers. A predictive setting time will allow the flow and timely of the material improving the overall apical seal.