Assessment of Physicochemical Properties, Cytotoxicity, Antimicrobial Activity, and Flexural Strength of Self-Cured Acrylic Resin With Silver Nanoparticles on Delaminated Clay for Removable Appliances.

Background and Aim: Silver nanoparticles represent a widely utilized nanotechnology product, prized for their versatile properties including electrical and thermal conductivity, and antimicrobial efficacy. This study aimed to assess the impact of incorporating silver nanoparticles-delaminated clay nanohybrid (AgNPs-DC) into acrylic resin on its antibacterial and antifungal characteristics, flexural strength, alongside evaluating the toxicity, and biocompatibility of the resultant composite. Materials and

Methods

Two concentrations of silver nanoparticles were initially integrated into the clay. Subsequently, cold-cure poly-methyl methacrylate (PMMA) was modified with varying percentages (0.2, 0.5, 1, and 1.5 wt%) of AgNPs-DC. Various analytical techniques including X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray (EDX) analysis, flexural strength, and elemental mapping were utilized to verify synthesis and determine physiochemical properties. Cytotoxicity assessments were conducted using mouse fibroblast cell line (L929), while antibacterial activity against standard strains of Escherichia coli (ATCC 25922), Enterococcus faecalis (ATCC 29212), and Candida albicans (ATCC 10239) were evaluated using the colony count method.

Results

EDX analysis confirmed the presence of clay and silver nanoparticles in the final acrylic resin. Samples with higher concentrations of silver nanoparticles (10%), AgNPs-DC (1.0% and 1.5%), and synthesized acrylic powder (80 µg/mL) exhibited increased cytotoxicity, with diminished cell viability after 5 days of incubation. Moreover, an escalation in AgNPs-DC concentration correlated with a significant reduction in colony counts of E. faecalis, E. coli, and C. albicans in groups with 5wt% of silver nanoparticles (p =  0.018, p <  0.001, and p =  0.004, respectively). Encapsulation of AgNPs-DC within the polymer mitigated its toxicity, while higher concentrations of silver nanoparticles (10%) demonstrated enhanced antimicrobial properties. The mean flexural strength in groups with concentrations of 0.2 and 0.5 wt% of AgNPs-DC was significantly higher than in groups with concentrations of 1 and 1.5 wt% of AgNPs-DC. (p <  0.05).

Conclusion

In conclusion, this study underscores the potential of PMMA modification with AgNPs-DC nanoparticles to confer satisfactory antibacterial and antifungal characteristics. Nonetheless, the cytotoxicity of the synthesized polymer increased with nanoparticle concentration and duration. Notably, ball milling proved effective in reducing nanoparticle aggregation.