Abstract
Aims: This study investigates the effects of the addition of magnesium oxide Nanoparticles(MgO NPs) with size (50 nm) on the flexural strength of cold˗cured acrylic resin. Materials and methods: Forty acrylic specimens were made, which divided into four groups (10 specimens for each group) which were control group (pure acrylic without addition), group of acrylic specimens containing 1.25% MgO NPs, group of acrylic specimens containing 2.5%MgO NPs, and a group of acrylic specimens containing 5%MgO NPs, the flexural test was performed using the universal testing machine, FTIR test performed using (BRUKER LASER CLASS 1). The statistical analysis was done by using SPSS program including descriptive statistics, ANOVA, and the Duncan΄s test at p ≤ 0.05. Results: The Maximum mean of flexural strength belong to the group with 1.25% of MgO NPs,the minimum mean of flexural strength belongs to a group with 5% MgO NPs. Conclusion: The addition of MgO NPs affected the flexural strength of the cold-cured acrylic resin, it improved the flexural strength at low concentration but decreased it at higher concentratios.