The effect of hydroxyapatite Nano fibers on impact strength and flexural strength and wettabilitty of heat-cured acrylic resins

Abstract

Several efforts have been done to strengthen and improve the mechanical properties of poly methyl methacrylate (PMMA). The current study also tried to investigate addition of hydroxyapatite nanofiber (n-HA) to PMMA on its flexural, impact strength and wettability. Materials and Methods: In this in vitro study, a control group that only included conventional thermosetting acrylic resin and four test groups, each containing acrylic resin plus 0.5 wt%, 1 wt%, 2 wt%, and 4 wt% n-HA were selected. After mixing n-HA with resin, the mixture was processed at standard flask. The flexural strength, impact strength and wettability of samples were measured. Mean SD and ANOVA test were used for statistical analysis. P value <0.05 considered statistically significant. Results: Although the flexural strength of reinforced acrylic resin with 0.5 wt% and 1 wt% were increased 25.5% and 23.5%, respectively, no significant difference was found in mean flexural strength between test groups (p> 0.05). Impact strength increase between experimental groups was significant (p <0.05). The highest increase in impact strength was observed in 1% and by increasing the amount of n-HA to 4% no significant change compared to 1 wt% was observed. There was a direct relationship between the wettability properties and the amount of n-HA in various samples. Conclusion: Addition of 1 wt% n-HA fibers to the heat cured acrylic resin results in 23% increases in the flexural strength and elevates impact strength to 115%.