The Effect of recycled polymethylmethacrylate...

The Effect of recycled polymethylmethacrylate Additive on the physical properties of Dental Modelling Wax

Author Name : *Amer A Taqa, Luma M. Al-Nema, Amrah Y.Al-Jmmal

ABSTRACT: Aim of the study: The aim of this study is to investigate the effect of recycled polymethylmethacrylate particlesaddedat the melting point,hardness, flow and linear thermal expansion properties. Material and Method: Modeling wax was prepared by mixing 65 grams of paraffin with 30 grams of beeswax.The modeling wax was prepared by melting the ingredients together under continuous stirring at the temperature 45°C in the water bath, after that 20% of recycled polymethylmethacrylate added slowly to mixture at 45°C and rapid mixing together untilobtaininga homogenous mixture. Then, the mixtures were poured into the molds and stored at room temperature for 24 hours prior totesting themelting point, flow, hardnessandthermalexpansiontesting. The results:The value of mean offlow of modeling wax with additive appeared less than control, the degree of mean of flow are about 60% while the mean of control 75%. The fore needle penetration test alsomodeling wax with additive appeared more harder than the control. Themean oflinear thermal expansion ofmodeling wax with additiveis decreased.There is a statistically significant difference at p≤0. 05 between modelling wax with additive and control. Conclusions: The addition of recycled polymethylmethacrylateparticles 20% to beeswax and hard paraffin leads to decrease the flow, thermal expansion and dimensional changes, but increase the melting point and hardness when compared with commercial modelling wax (control).