Rheological properties and handling characteristics of four injectable calcium hydroxide pastes

The aim of this study was to investigate the rheological properties and handling characteristics of four brands of injectable calcium hydroxide pastes (Calcipex II, CleaniCal, DiaPaste, Well-Paste). Shear viscosity was measured with a rotational rheometer. A universal mechanics analyzer assembled in the laboratory was used to quantify the force for extrusion and extruded weight of the materials. The apical pressure during injection into an artificial root canal was measured using a pressure sensor. All materials exhibited pseudoplastic behavior. The force for extrusion was highest for DiaPaste, and lowest for CleaniCal, while the extruded weight was lowest for DiaPaste and highest for CleaniCal (p<0.05), indicating a need for caution when using CleaniCal. However, the pressure generated at the apex may vary depending on the shape, and taper of the needle tip, as well as the viscosity of the materials.