Bio-Functionalized Green Silver Nanoparticles for Dental Biomaterials: A Prisma-Compliant Systematic Review on Antimicrobial Efficacy and Biological Safety

Abstract

Background: Conventional chemical synthesis of silver nanoparticles (AgNPs) frequently leaves toxic solvent residues that compromise biological compatibility in dental applications. Phytogenic green synthesis offers an eco-friendly alternative, utilizing plant polyphenols for simultaneous ionic reduction and surface capping.

Objectives: To systematically appraise and quantitatively synthesize in vitro evidence regarding the antimicrobial efficacy, antioxidant activity, and eukaryotic cytocompatibility of plant-mediated green AgNPs relative to conventional chemical formulations and dental disinfectants.

Data Sources: Medline (via PubMed), Scopus, Web of Science, and Embase were searched systematically with no specific duration restriction upto May 2026.

Eligibility Criteria & Parameters: Controlled in vitro laboratory studies evaluating green-synthesized AgNPs against oral pathogens (Streptococcus mutans, Enterococcus faecalis), radical scavenging efficiency ("DPPH"/"ABTS" ), and mammalian cell viability (Human Gingival Fibroblasts [HGFs], L929, hDPSCs) adhering to ISO 10993-5 standards.

Study Appraisal: Methodological quality and risk of bias (RoBINS) were evaluated using the Quality Assessment Tool for In Vitro Studies (QUIN).

Results: Five primary quantitative laboratory investigations (N=5) met all eligibility criteria. Risk of bias analysis via QUIN categorized one study as High Quality (83.3%) and four as Medium Quality (58.3%–66.7%). Meta-analysis using a DerSimonian-Laird random-effects model revealed a statistically significant increase in the Zone of Inhibition ("ZOI" ) against S. mutans for green AgNPs compared to chemically synthesized controls ("WMD"=+5.23" mm" , 95%" CI":+3.81" to "+6.65" mm" ; p<0.001;I^2=73.0%). Antioxidant capacity yielded 〖"IC" 〗_50 values ranging between 29.4" and " 54.2" "\upmu"g/mL" . Mean mammalian cell viability exceeded the ISO 10993-5 standard (>70%) across therapeutic antimicrobial doses (12.5"--" 31.25" "\upmu"g/mL" ).

Limitations: High inter-study heterogeneity stemming from non-standardized plant extract compositions, variable crosshead speeds/disk dimensions, and a lack of dynamic intraoral simulations (e.g., artificial saliva, thermocycling, mechanical loading).

Conclusions: Green-synthesized AgNPs display superior antimicrobial efficacy against primary cariogenic pathogens and robust antioxidant capabilities while preserving human dental cell cytocompatibility at active microbicidal concentrations.