Physicomechanical properties of PMMA denture base resins reinforced with nanofibers: a systematic review and meta-analysis.

OBJECTIVE: Despite the potential of nanofibers to reinforce poly(methyl methacrylate) (PMMA) denture base resins, no consensus exists regarding their effects on material properties. This systematic review and meta-analysis aimed to evaluate whether the incorporation of nanofibers into PMMA denture base resins improves flexural strength and other physicomechanical properties when compared with unmodified PMMA. METHODOLOGY: This study followed PRISMA guidelines and was registered on the Open Science Framework (). Searches were conducted on Medline/PubMed, Scopus, Cochrane Library, Web of Science, EMBASE, Lilacs, and SciELO. Eligibility criteria included in vitro or in vivo studies comparing nanofiber-reinforced PMMA to conventional PMMA. The meta-analysis was conducted for flexural strength (the only property assessed in all studies). A subgroup meta-analysis was performed to explore heterogeneity between studies. RESULTS: From the 1,893 initially screened articles, six were included. The investigated nanofibers included carbon, acrylonitrile-butadiene-styrene, polyamide-6, polystyrene, cellulose, PMMA-cerium, and polyvinyl alcohol at concentrations from 0.1 to 23%. The evaluated properties included impact strength, flexural strength, fracture resistance, hardness, elasticity, toughness, surface roughness, contact angle, and spectrophotometric color analysis. While the qualitative analysis showed divergent findings regarding property improvement, the quantitative analysis revealed no significant differences in flexural strength between nanofiber-reinforced PMMA and conventional PMMA at the evaluated concentrations: PMMA vs. 0.5% PMMA (p=0.554), PMMA vs. 1% PMMA (p=0.847), PMMA vs. 3% PMMA (p=0.9825), and PMMA vs. 5% PMMA (p=0.222). However, subgroup analysis indicated higher flexural strength for the conventional PMMA when compared with nanofiber-reinforced PMMA, particularly at higher nanofiber concentrations (p<0.0001). CONCLUSION: Incorporating nanofibers into PMMA resulted in no significant increase in flexural strength, showing inconsistent effects on other physicomechanical properties. Therefore, further standardized laboratory and clinical studies are needed to clarify its efficacy and clinical applicability.