Effectiveness of chicken eggshell-derived remineralizing agents on enamel microhardness after bleaching: A systematic review and meta-analysis

Introduction: Dental bleaching may reduce enamel microhardness by causing mineral loss, highlighting the need for effective remineralization strategies. Aim: This review aimed to evaluate the effectiveness of chicken eggshell-derived remineralizing agents, compared with casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) and other natural agents, in improving enamel microhardness. Methods: A literature search was conducted across PubMed/MEDLINE, Scopus, Web of Science, the Cochrane Library, EMBASE, EBSCO, and DOAJ. Additional grey literature and manual searches were conducted. Eligible in vitro studies that assessed enamel microhardness after treatment with chicken eggshell paste (CESP), CPP-ACP, or other natural remineralizing agents were included. A meta-analysis was conducted using RevMan. Results: The review includes six in vitro studies. CESP significantly improved enamel microhardness compared to controls and had remineralization potential equal to or better than that of CPP-ACP and grape seed extract in the meta-analysis. Baseline comparisons showed no significant differences, whereas postremineralization results favored eggshell-derived materials. Discussion: CESP is an effective remineralizing agent that enhances enamel microhardness after bleaching and may be a promising alternative to traditional remineralizing agents.