Evaluation of the Transverse Strength of the Heat Cure PMMA Resin Reinforced with Various Concentrations of Two Different Nanoparticles: An In vitro Study

Purpose: The purpose of the study was to evaluate the effect of titanium dioxide and zirconia nanoparticles on transverse strength of heat cure PMMA resin routinely used for complete denture fabrication.

Methods: One hundred samples of PMMA resin were made and divided into five groups (20 samples for each group). The test specimens were divided into five groups depending on the concentration of reinforcing nanoparticles as Group 1,2,3,4 and 5; Group 1: PMMA unreinforced (control group), Group 2: PMMA reinforced with 2.5% nanozirconia, Group 3: PMMA reinforced with 5% nanozirconia, Group 4: PMMA reinforced with 2.5% titanium dioxide nanoparticles, and Group 5: PMMA reinforced with 5% titanium dioxide nanoparticles. Universal testing machine was used to conduct a three-point bending test and evaluate the transverse strength of samples. Comparison of mean transverse strength for various groups was carried out by employing one‑way analysis of variance and Bonferroni post hoc tests.

Results: The highest and lowest mean transverse strength were observed in Group 3 and 1, respectively. Bonferroni post hoc test showed increase in transverse strength after reinforcement to be statistically significant between all the groups (P = .05) except between the samples of group G1 and G5 and G2 and G3.

Conclusion: Addition of nanoparticles in all concentrations significantly increased transverse strength of heat cure PMMA resin as compared to control group. The best result was obtained after adding 5% of nanozirconia particles to the conventional heat polymerized acrylic resin.