An ultrasonic-based experimental model to evaluate the setting time of endodontic sealers

To evaluate an ultrasonic-based experimental model (US), to assess the setting time of AH Plus^® , Bio-C Sealer^® and MTA Fillapex^® , and compare the results obtained with ANSI/ADA specifications (2012).

To determine the setting time according to the ANSI/ADA specification, moulds measuring 10 mm (diameter) × 2 mm (thickness) were used, and for the US tests a transducer (1 MHz) and an oscilloscope were used. Fourier-transform infrared spectroscopy (FTIR) was used to evaluate the changes on chemical structure at the different setting times found by the US and ANSI/ADA methods. After checking the normal distribution, setting time data were analysed using unilateral analysis of variance with Tukey-HSD post-test to compare the methods.

AH Plus^® and Bio-C Sealer^® had longer mean setting time values for the US method than for the ANSI/ADA (p < .05), whilst for MTA Fillapex^® no significant difference was found between the methods (p < .05). FTIR spectra demonstrated that at the setting time determined by the US method, AH Plus^® and Bio-C Sealer^® were in a more advanced stage of polymerization than at the ANSI/ADA, whilst there was no significant difference for MTA Fillapex^® .

The use of US was effective for setting time determination and measured longer values than ANSI/ADA specification for AH Plus^® and Bio-C Sealer^® , identifying the entire (and not only superficial) setting of the endodontic sealers.