Comparison of the thermal conductivity and flexural strength of self cured and heat cured acrylic resin with and without nano-oxide aluminum

Abstract

Introduction: The mechanical and thermal properties of polymethyl methacrylate, the most common substance used in the manufacture of dental prostheses, should be strengthened due to its structural weakness. The purpose of this research was to compare the flexural strength and thermal conductivity of two types of heat and self cured acrylic resin reinforced with nano aluminum oxide and pure acrylic substance. Materials and methods: For conducting this research, 114 specimens including 6 groups with 11 samples were provided for thermal conduction test and 6 groups with 8 samples for test of flexural strength. According to the percentage of nano- oxide aluminum in each test they were divided into two subgroups with 3 samples of cooked and self-cured. In each subgroup, a group of specimens (11 specimens for thermal conduction and 8 specimens for flexural strength) including one percent and other group including three percent of nano- oxide aluminum from Sigma Aldrich were prepared. Other group as control group lacked nano- oxide aluminum. The flexural strength and thermal conduction tests were conducted on the specimens. Kolmogorov-Smirnov test was used for evaluation of normality of data distribution and One-way ANOVA was employed for statistical analysis. The Tukey test was used as a suitable posthoc test for pairwise comparison of mean value. P <0.05 was considered statistically significant in this study. Results: An increase in the percentage of nano aluminum oxide in acrylic samples increased thermal conductivity and decreased flexural strength (P<0.05). Conclusion: The addition of nano aluminum oxide negatively affected the acrylic flexural strength but increased its thermal conductivity.