Silver Nanoparticles (AgNPs) Incorporation into Polymethyl Methacrylate (PMMA) for Dental Appliance Fabrication: A Systematic Review and Meta-Analysis of Mechanical Properties

Abstract

Polymethyl methacrylate (PMMA), widely used in orthodontics and dentures, exhibits suboptimal mechanical properties, including flexural strength (FS), impact strength (IS), and tensile strength (TS), which are critical for ensuring durability, resistance to fracture, and overall functionality of dental appliances. Silver nanoparticles (AgNPs) are a promising filler due to their antimicrobial properties. This pre-registered (osf.io/yqftx) PRISMA-compliant meta-analysis compared the mechanical properties of PMMA/AgNP composites to pure PMMA, considering mean particle size and concentration. Of 360 records from ACM, BASE, PubMed, and Scopus, 35 studies were included (κ = 0.91), covering 88, 38, and 11 tests on FS, IS, and TS, respectively. FS increased only between 30-70 nm (r = 0.00; ρ = 0.03; R²_deg2 = 0.13). IS remained higher for <80 nm and increased between 15 and 25 nm (r = -0.41; ρ = -0.28; R²_deg2 = 0.59). TS favored 55 nm but had limited data (r = -0.24; ρ = 0.63; R²_deg2 = 0.99). FS decreased with increasing wt%, showing no discernible trend (r = -0.22; ρ = -0.34). IS increased within 0.0-4.0 wt%, particularly 0.5-2.0 wt% (r = -0.15; ρ = -0.35; R²_deg2 = 0.54). TS peaked at 0.5-2.0 wt% (r = -0.20; ρ = -0.24; R²_deg2 = 0.91). Optimal mechanical properties of PMMA/AgNP likely fall within 15-70 nm mean nanoparticle size and 0.5-4.0 wt% concentration.

Keywords: dentures; mechanical tests; nanoparticles; polymethyl methacrylate; silver.

Figure 1

Flow diagram.

Figure 2

Flexural (A), impact (B), and tensile (C) strength to AgNP mean particle size.

Figure 3

Flexural (A), impact (B), and tensile (C) strength to AgNP concentration.