Assessing Viscosity and Flowability of Endodontic Sealants

Abstract

Aim: An in vitro study to assess the apparent viscosity and flowability of three commercial root canal sealants (BioRoot Flow®, GuttaFlow Bioseal® and AH Plus®) and to explore potential correlation between viscosity and flow.

Materials and Methods: Apparent viscosity of the endodontic sealants was measured using a syringe-based viscometer. The protocol was developed and validated using standard viscosity fluids (4872 mPa.s and 11130 mPa.s). The methodology incorporated the Hagen–Poiseuille equation and calibration correction factors to account for errors in the protocol. All tests were conducted at a controlled temperature of 25°C. Flowability was assessed using the ISO 6876:2012 simple press method.

Results: The method yielded reproducible viscosity results with error margins under ±3%. Among the sealants tested, BioRoot Flow® showed the highest apparent viscosity (16931 mPa.s), followed by GuttaFlow Bioseal® (10136 mPa.s) and AH Plus® (8624 mPa.s). All sealants exhibited acceptable flowability, with values exceeding the ISO minimum (17 mm), ranging from 22.4 mm to 23.5 mm. There was no correlation between viscosity and flow values.

Conclusion: The developed syringe-based viscometer protocol proved valid for measuring the apparent viscosity of endodontic sealants. While viscosity varied between materials, flowability remained closely similar between the tested sealants, indicating other factors such as particle size, composition, and temperature influencing the flow. These findings offer a useful framework for future research on rheological characteristics of root canal sealants.