Assessment of the effects of aluminum oxide powder on some physical properties of a heat cure acrylic resin

Acrylic resin is a thermal consulator which is a great disadvantage for this material. In some studies Al2O3 is added to polymethyl methacrylate to improve its thermal conductivity. The purpose of this experimental study is evaluation of some physical properties of the acrylic resin mixed with Al2O3, such as transverse strength, transverse deflection, modulus of elasticity and hardness. Methods & Materials: Three groups of acrylic resin (Meliodent, Bayer UK heat cure acrylic resin) each consisted of 20 specimens were prepared. The first group was control (pure acrylic resin), the second group was PMMA specimens with 15% (weight percentage) Aluminum oxide powders (Martinswerk, Germany) and the third group was PMMA specimens with 20% Aluminum oxide. The transverse strength, transverse deflection and modulus of elasticity were measured by use of universal testing machine (Dartec) and the dimensions of specimens were 65×10×2.5 mm loading speed was 1mm/min. Hardness was measured by use of Brinel hardness tester machine. The dimensions of specimens were 20×20×5 mm. Analysis of variance and Duncan test were used for data analysis. Results were based on Mean±standard deviation. There was a significant difference between the mean of transverse deflection between control group and test groups (p.v=0.004). But Duncan test revealed that there was not significant differences between the test groups.The mean of modulus of elasticity of test groups and control had significant differences (p.v=0.007) but Duncan test showed no differences between test groups. The mean of transverse strength and hardness of groups showed no differences. This study showed that the mixing of Aluminum oxide and acrylic resin, decreases transverse and deflection strength and increases modulus of elasticity of modified resin but it has no effect on resin hardness.