The aims of this study were to evaluate the effect of change in time, temperature (increase or decrease) and some additives(Nigella sativa and Thyme oil) on the degree of conversion, residual monomer release, transverse strength, indentation hardness, volumetric and color changes of the vertex heat cured acrylic resin.The results of the present study were analyzed statistically by (Descriptive statistics, ANOVA and Duncan's multiple range test). The results of this study showed that both changes in time and temperature showed significant changes in the degree of conversion, residual monomer,...