A comparative evaluation of impact strength of conventionally heat cured and high impact heat cured polymethyl methacrylate denture base resins: an in vitro study

Impact Strength of Various Types of Acrylic Resin: An In Vitro Study

AIM

The aim of this study is to evaluate and compare the impact strength of conventional acrylic resin, high-impact acrylic resin, high-impact acrylic resin reinforced with silver nanoparticles, and high-impact acrylic resin reinforced with a zirconium oxide powder.

MATERIALS AND METHODS

A total of 60 samples were prepared of dimensions 60 mm length × 7 mm width × 4 mm thickness to test impact strength. Machined stainless steel dies of the same dimension were used to form molds for the fabrication of these samples. Of 60 samples, 15 samples were prepared each from conventional acrylic resin (Group A1), high-impact acrylic resin (Group A2), acrylic resin reinforced with silver nanoparticles (Group A3), and acrylic resin reinforced with zirconium oxide powder (Group A4). Izod-Charpy pendulum impact testing machine was used.

RESULTS

The impact strength of group A1 was in the range of 2.83-3.30 kJ/m² (M = 3.12 kJ/m², SD = 0.16), group A2 was in range of 5.10-5.78 kJ/m² (M = 5.51 kJ/m², SD = 0.18), group A3 was in range 3.18-3.56 kJ/m² (M = 3.37 kJ/m², SD = 0.11), and group A4 was in range 7.18-7.78 kJ/m² (M = 7.5 kJ/m², SD = 0.18). Statistical analysis using one-way ANOVA and t-test revealed significant differences (p < 0.001).

CONCLUSION

High-impact acrylic resin reinforced with zirconium oxide powder has the highest impact strength.

CLINICAL SIGNIFICANCE

This research sheds light on the usefulness of novel filler materials in clinical prosthodontics.

The Impact of Polymerization Technique and Glass-Fiber Reinforcement on the Flexural Properties of Denture Base Resin Material

OBJECTIVE

 Different polymerization and reinforcement techniques have been tested to enhance the mechanical characteristics of denture base acrylic resins. The goal of the present study was to evaluate the influence of autoclave polymerization techniques with glass fiber reinforcement on the flexural strength and elastic modulus of polymethyl methacrylate denture base resins.

MATERIALS AND METHODS

 Ninety specimens were fabricated from heat-polymerized acrylic resin and randomly distributed depending on the polymerization technique into three groups (n = 30): water bath polymerization, short-cycle autoclave polymerization, and long-cycle autoclave polymerization. Each group was further divided into three subgroups (n = 10) based on the concentration of glass fiber 0, 2.5, and 5wt%. The flexural strength and elastic modulus were investigated using a universal testing machine. One-way ANOVA and Tukey's post hoc test were performed to analyze the results (α = 0.05).

RESULTS

 The flexural strength and elastic modulus values were significantly higher in 5wt% glass fiber reinforced long-cycle autoclave group in comparison with the other test groups (p < 0.05).

CONCLUSIONS

The long-cycle autoclave polymerization technique with the glass fiber reinforcement significantly increased the flexural strength and elastic modulus of the denture base resin material.