Evaluation of the Effects of ZnONPs, Standard AgNPs, and Im-AgNPs Nanoparticles on the Microhardness of Root Canal Dentin: A Systematic Review and Meta-analysis

Background and aim: The present study aimed to evaluate the effect of  Zinc Oxide (ZnONPs), Standard Silver(AgNPs), and Imidazolium-based Silver (Im-AgNPs) nanoparticles on the microhardness of root canal dentin. Material and methods: The literature was screened via international databases Cochrane, Embase, and MEDLINE (PubMed and Ovid) up to October 2024 with English language restriction. Two reviewers independently performed screening and evaluation of articles. The ToxRTool® checklist information contained eighteen items to evaluate Methodological quality. The mean difference was used as an effect size indicator to analyze each included study. The fixed-effect model with the Inverse–variance method combined the effect size. All meta-analyses were performed using Stata software (version 17). Results: A total of 219 articles were retrieved from all the databases; after applying eligibility criteria, seven studies were included. Immersion in standard AgNP irrigant significantly increased the VHN compared to the control group in the coronal (MD: 16.13 95% CI; 15.39-16.86; P˂0.001). Immersion in Im-AgNPs significantly increased the VHN in the middle (MD: 6.60 95% CI; 1.90-11.31; P˂0.05) and apical  (MD: 10.25 95% CI; 5.78-14.72; P˂0.001). ZnONPs irrigant increased the VHN, compared to the control group in the coronal (MD: 10.92 95% CI; 10.13-11.71; P˂0.001). Conclusions: Based on the present meta-analysis, root canal irrigants containing ZnONPs, Standard AgNPs, and Im-AgNPs can improve the microhardness of root canal dentin in coronal, middle, and apical regions.