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

Abstract

Aim 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). Methods 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. Results 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®. Conclusions 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.