The Reinforcement Effect of Nano-Zirconia on the Flexural Strength and Impact Strength of Microwaved and Heat Cured Acrylic Resin

Document Type : Original Article


1 Demonstrator in Dental Biomaterials Department, Sinai University, North Sinai, Egypt.

2 Assistant Professor of Dental Biomaterials and Head of Dental Biomaterials Department, Faculty of Dentistry, Sinai University, North Sinai, Egypt.

3 Assistant Professor and Head of Dental Biomaterials Department, Faculty of Dental Medicine for Girls, Al-Azhar University, Cairo, Egypt.


Purpose: This study was conducted to evaluate the effect of adding nano-zirconia with different concentrations on the flexural and impact strength of microwaved and heat cured acrylic resin. Materials and Methods: The silanized nano-ZrO2 particles (nano-zirconia) were added to PMMA powder for both heat polymerized and microwaved acrylic resin. A total of 160 specimens were prepared from both types of acrylic resin (n=80). For both types of acrylic resin, specimens for each strength test were subdivided into 4 subgroups (n=10): a control group (with no fillers) and three reinforced groups with 3 concentrations (3%, 5% and 7%) wt. % of nano-ZrO2 fillers. Flexural strength was measured using an Instron mechanical testing machine and impact strength was measured by Charpy tester. Results: For the heat cured resin 3% nano-zirconia showed the highest mean fl exural strength value followed by 5 % nano-zirconia. For the microwaved acrylic resin, 3% nano-zirconia showed the highest mean flexural strength value while 5% and 7% led to decrease in the flexural strength value. For the impact strength results, increasing nano-zirconia percentage led to decrease the impact strength for both types of acrylic resin. Conclusions: The incorporation of 3% and 5% nano-zirconia into heat cured acrylic resin improved its fl exural strength but 7% of nano-zirconia addition had a deteriorating effect on the flexural strength of both types of resin investigated. Moreover, the addition of nano-zirconia to both types of acrylic resin had a negative effect on their impact strength.


Main Subjects

Volume 10, Issue 1
Issue1 January-Restorative Dentistry issue (Removable Prosthodontics, Fixed Prosthodontics, Endodontics, Dental Biomaterials, Operative Dentistry)
January 2023
Pages 1-10