Impact of Silanized Zirconium Silicate Nanoparticles on Flexural Strength of PMMA Denture Base Material

Abstract

Introduction: Edentulism, the complete loss of teeth, remains a significant concern, especially among the elderly population. Various treatment modalities, including removable dentures and implant-supported restorations, are available to restore function and aesthetics in edentulous patients. Polymethyl methacrylate (PMMA) has been widely used for denture base fabrication due to its biocompatibility, ease of processing, and aesthetic properties. However, PMMA’s mechanical limitations, such as poor flexural strength and brittleness, often lead to fractures. To address these issues, researchers have explored the incorporation of nanoparticles, such as silanized zirconium silicate (ZrSiO₄), to enhance the mechanical properties of PMMA.

Aim: The study aimed to evaluate the impact of varying concentrations of silanized zirconium silicate nanoparticles on the flexural strength of heat-polymerized PMMA denture base material.

Materials and Methods: An in vitro study was conducted using heat-polymerized PMMA specimens, divided into six groups: one control group and five groups reinforced with different concentrations (1.5%, 2%, 2.5%, 3%, and 4%) of silanized zirconium silicate nanoparticles. Sixty specimens were prepared and subjected to flexural strength testing using a three-point bending test. Data were analyzed using one-way ANOVA and Tukey's post-hoc test to compare the mean flexural strength between groups.

Results: The incorporation of silanized zirconium silicate nanoparticles significantly enhanced the flexural strength of the PMMA specimens compared to the control group. The highest flexural strength was observed in the group reinforced with 1.5% ZrSiO₄ nanoparticles (105.3 MPa), followed by the group with 2% reinforcement (103.8 MPa). Beyond 2%, the increase in nanoparticle concentration resulted in a slight plateau or decline in performance. Statistical analysis confirmed significant differences between the control and reinforced groups (p < 0.001).

Conclusion: Reinforcement of heat-polymerized PMMA denture base material with silanized zirconium silicate nanoparticles effectively improves its flexural strength, with the optimal concentration being 1.5%. Further research may focus on long-term clinical evaluations and the impact of nanoparticle reinforcement on other mechanical properties, such as fatigue resistance and toughness.