Setting time of calcium silicate-based sealers at different acidic pHs

Aim: To evaluate the effect of root canal sealer type (calcium silicate- or epoxy amine resin-based sealer) and solution/pH (acidified or buffered at pH 7.4, 6.4, 5.4, and 4.4) on their setting time. Materials and Method: Samples of BIO- C Sealer (Angelus), EndoSequence BC Sealer (Brasseler), BioRoot RCS (Septodont), and AH Plus Jet (Dentsply) were manufactured into 10-mm internal diameter rings and exposed to gauzes soaked with different solutions (n=6): PBS at pH 7.4 (control), acidified PBS at 6.4, 5.4, and 4.4, as well as butyric acid buffer at pH 6.4, 5.4, and 4.4. The setting time of the sealers was determined when the indentation of a 100-g- weight Gilmore needle was no longer visible on the top surface of the samples (ISO 6876:2012 guidelines). The data were analyzed by a repeated measures analysis of variance (Mixed ANOVA) (alpha= 0.05). Results: All sealers were set within 24 hours. EndoSequence BC Sealer and BioRoot RCS respectively exhibited the longest and the shortest setting times among all sealers and there was a significant difference between them at all solutions/pH (p<0.05); however, their setting time did not significantly vary regardless of solution/pH (p>0.05). The setting time of the BIO-C Sealer significantly increased when exposed to acidified PBS at pH 4.4 (p<0.01), and butyric acid buffer solutions at pH 6.4, 5.4, and 4.4 (p<0.01). The longest setting times observed for BIO-C Sealer were not significantly different from those observed for EndoSequence BC Sealer (p>0.05). The setting time of AH Plus Jet significantly decreased only when exposed to acidified PBS at pH 4.4 (p<0.05). Conclusions: The setting time of only one calcium silicate-based sealer (BIO-C Sealer) was significantly increased when exposed to some acidic pH conditions. Both the shortest (BioRoot RCS) and the longest (EndoSequence BC Sealer) setting times were observed for calcium silicate-based sealers. BioRoot RCS demonstrated the shortest setting time regardless of solutions/pH and seems the most suitable for root canal treatment in acidic environments.