Evaluation of thermal conductivity of alumina reinforced heat cure acrylic resin and some other properties

الملخص EN

Background : The polymethylmethacrylate is the most reliable material for the construction of complete and partial dentures, but it has been shown to be lacking an important property which is it's thermal conductivity, where thermal conductivity play an important role in patient satisfaction with complete and partial dentures.

This study was designed to improve the thermal conductivity of acrylic resin by adding alumina powder and investigate the effect of this additive filler (Al2O3 powder) on some properties of heat cure PMMA denture base material. Materials and methods : Alumina powder was added to PMMA powder by weight in three different percentages 5%, 7.5% and 10% , 240 specimens were constructed and divided into 6 groups according to the test and each group was subdivided into 4 sub groups according to the percentage of added alumina.

The test conducted were thermal conductivity by the use of Lee's disc, water sorption and solubility , surface roughness , surface hardness ( Shore D), impact strength ( un notched ) and tensile strength .

Data were analyzed by one way analysis of variance test (ANOVA) and least significant differences (LSD). Results : A highly significant increase in thermal conductivity occurred with the addition of Al2O3 powder while a significant reduction occurred in both impact and tensile strength specimens' tests.

Highly significant increase in surface hardness was observed.

Also water sorption and solubility decreased significantly.

Surface roughness was not affected except a significant increase was observed in surface roughness by the addition of 10% Al2O3 to PMMA. Conclusion : The addition of Al2O3 powder to acrylic resin improves the thermal conductivity of acrylic resin, at the same time this addition decreases both impact and tensile strength values.

On the other hand there was an increase in surface hardness, water sorption and solubility were decreased while surface roughness not affected with small percentages of alumina.