Effect of HNTs and MWCNTs nanotubes on the impact strength and hardness of PMMA denture base

Polymethyl methacrylate (PMMA) resin is commonly used for the fabrication of a denture base for heat curing polymerization. The objective of this work to investigate the effects of using two types of nanotube technology: Halloysite nanotubes (HNTs) and Multi-walled carbon nanotubes (MWCNTs), on the impact strength (IS), and Vickers hardness (VH) of PMMA denture base. The denture base composites were fabricated by incorporating PMMA powder, 0.5wt% of benzoyl peroxide (BPO), fixed nanotubes at 5wt% of HNTs / MWCNTs(5/0, 4.5/0.5, 4/1, 3.5/1.5, and 0/5) nanotubes as powder components. PMMA powder was mixed with a liquid (made from 90% methyl methacrylate (MMA) and10% ethylene glycol dimethyl-acrylate (EGDMA), as a crosslinking agent). The results show that the mean of impact strength significantly increased by the incorporation of 5wt% of HNTs/MWCNTs nanotubes with the ratio of (4:1 wt%) by 10.51 KJ/m2compared to unenhanced PMMA. However, the Vicker's hardness of the PMMA decreased by incorporation of 5wt% of HNTs/MWCNTs nanotubes, to17.42kg/mm2. The addition of HNTs and MWCNTs nanotubes to the PMMA matrix improved the impact strength but not the Vicker's hardness. Therefore, hybrid reinforced PMMA denture base composite with HNT and MWCNT nanotubes fillers is appropriate to be used for high performance prosthodontics applications.