Abstract

Background: Still Heat cure acrylic is the Most widely used denture base materials.but it has some inadequate properties like strength and antimicrobial activity .the present aimed to study the use of ascorbic acid as fillers with water bath and autoclave heat cure denture base material .And evaluate its effect on some properties of heat cure acrylic. Materials and Method: in this study , vertex regular heat polymerized resin were used to prepare specimens in two method of polymerization autoclave and water bath polymerization .the curing cycle for autoclave was (134 °C ,2bar,15minutes).while for heat cure (20 °C to100 °C, for 30 minutes at 100 °C). The effect of Ascorbic acid was used in two form addition for and immersion form with a concentration of 1%. And 30 minutes was the time for immersion. the data were analyzed using ANOVA tests which was considered statistically significant at a level of< 0.05. Results: Autoclave polymerized showed a non-significant increase for flexural strength with incorporation and immersion form with highest mean value (101.05+SD 5.02) (100+SD 4.19) respectively. Also, for hardness the water bath showed a non-significant increase in incorporation form with highest mean value (83.76+ SD1). While a non-significant decrease in the flexural and impact for water-bath with two form, and non-significant decrease in the immersion form for water bath. Also, there was a non-significant decrease for autoclave in hardness and impact with two forms Conclusion: Adding 1% ascorbic acid to the heat cure acrylic showed no effect on the mechanical properties for heat cure polymerized by Autoclave and water-bath meanwhile there was a significant increase in the mean value of Autoclave polymerized when compare with water-bath polymerized. Keywords: Ascorbic acid, Autoclave polymerization, water-bath polymerization, Micro-Particles, impact strength, flexural strength, hardness.