IMPACT STRENGTH OF AN EXPERIMENTAL POLYURETHANE- BASED POLYMER

Abstract

The impact strength of a newly developed experimental polyurethane-based polymer which is derived from palm oil (Experimental PU) was compared with denture polymers; heat-cured and self cured polymethyl methacrylate (PMMA) and Eclipse®, light-activated urethane dimethacrylate prosthetic resin system. Ten specimens were prepared using heat-cured PMMA (Meliodent® Heat Cure, Heraeus Kulzer, Germany), self cured PMMA (Meliodent® Rapid Repair, Heraeus Kulzer, Germany), Eclipse® baseplate resin (Dentsply, USA) and Experimental PU material. Specimens were prepared following manu- facturer’s instructions except for the Experimental PU material where it was prepared in bulk and sectioned to the desired dimension, 64 x 6 x 4 mm. A ‘V’ notch of approximately 0.8mm in depth was machine cut across the 6mm width. Prior to the Charpy type impact test, specimens were soaked in a water bath for 50 hours at 37oC. Eclipse® baseplate resin showed the highest impact strength (2.73 kJ/m2±0.54) followed by Meliodent® Rapid Repair (2.50kJ/m2±0.65), Meliodent® Heat Cure (1.96kJ/m2±0.42) and Experimental PU (1.04kJ/m2±0.29). One-way ANOVA showed significant interaction between materials (p<.05) and Tukey HSD revealed that Experimental PU exhibited significantly lower impact strength compared to other materials. Meliodent® Rapid Repair was not significantly different from Meliodent® Heat Cure and Eclipse® baseplate resin. It can be concluded that the Experimental PU exhibited the lowest impact strength while Eclipse® baseplate resin the highest.