The influence of particle size and multi-walled carbon nanotube on physical properties of mineral trioxide aggregate

Abstract

The objectives of this study are to reduce the particle size distribution of Mineral Trioxide Aggregate (MTA) and to investigate its impact on setting time, radiopacity, flexural and compressive strength. Furthermore, the effect of adding multi-walled carbon nanotube to MTA composite was studied. MTA particles sizes were decreased using Wet-Stirred-Media-Milling (time intervals of 5, 10, 15 and 20 h). The distilled water and multi-walled carbon nanotube (0.25%, 0.5%, 0.75% and 1 wt%) were mixed and added to the MTA for hydration. MTA setting time, flexural and compressive strength and radiopacitiy were measured. Moreover, the unset MTA was analysed using x-ray-diffraction and the surface of the set MTA was observed by scanning electron microscopy. Tukey’s HSD test shows that initial and final setting times were decreased significantly up to 15 h of milling (p < 0.05). Flexural/Compressive strength of MTA were significantly decreased after milling for 10 and 20 h (p < 0.05). The flexural strength and compressive strength of the specimens reinforced with MCNTs show an increase of 76% and 10.2%, over plain MTA specimens. The results suggest that MTA setting-time can be accelerated and regulated by reducing particle size distribution without adding chemicals. The mechanical properties of MTA were significantly improved with the addition of multi-walled carbon nanotube without negative impact on setting time. In this study, a Nano Fast Cement composite with short setting time and high strength was developed by modification of MTA material.