Comparative evaluation of chitosan as irrigant on microhardness of residual dentin structure: A systematic review and meta-analysis

Aim: This article aims to systematically review the published in vitro studies comparing the effects of two distinct chelating irrigants, namely ethylenediaminetetraacetic acid (EDTA) and chitosan, on dentinal microhardness. Methods: The Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were followed, and the protocol was registered in PROSPERO (registration number: CRD42024562708). The research question developed was whether 0.2% chitosan irrigation affects the radicular dentin microhardness following the PICOS criteria. It aims to identify, compile, and systematically analyze the data available for the 12-year period from January 2012 to December 2024. The literature search was conducted on PubMed-MEDLINE, Google Scholar, and SCOPUS, and then, the articles were assessed by three independent reviewers. A total of 7 papers out of 293 titles met the eligibility criteria. Results: EDTA reduced dentin microhardness to a greater extent compared to 0.2% chitosan, regardless of changes in various parameters. Conclusion: There is less reduction in microhardness when using 0.2% chitosan as the final irrigant compared to EDTA. Due to its conservative effect on residual radicular dentin and its biocompatible nature, it may replace EDTA in the future as a chelating and final irrigant.