Evaluation of the flexural strength of orthodontic acrylic resin incorporated with propolis nanoparticles: an in vitro study

Aim : Nanopropolis has become the subject of interest in medicine and dentistry as a natural product due to its outstanding properties, particularly antimicrobial activity. This study aimed at investigating the effect of nanopropolis on flexural strength of polymethyl methacrylate (PMMA). Materials and methods : Three groups of two acrylic resin brands namely Acropars and Triplex containing 0 (control group), 0.5%, and 1% of nanopropolis were prepared in 64×10.0×3.3 mm according to ISO 20795-2 (2013). Fifteen samples were allocated to each concentration. Flexural strength was determined following immersion in water and incubation at 37°C for 50±2 hours using a universal testing machine at a crosshead speed of 5±1 mm/min. Data were analyzed using ANOVA, Tukey HSD, and t -test. P <0.05 was set as statistical significance. Results : Control groups of Acropars and Triplex showed the highest mean flexural strength within their own group which both were higher than the recommended 50 MPa. The mean flexural strength of Triplex incorporated with 0.5 and 1% of nanopropolis was higher than that of Acropars with the same percentage. Conclusions : The mean flexural strength of Triplex remained above the recommended value of 50 MPa after incorporation of both 0.5 and 1% nanopropolis. However, that of Acropars dropped below it.