Methods for testing bioactivity of hydraulic cements for root-end filling

Abstract

<p>Objectives <br>To summarize <em>in vitro</em> testing methods for evaluating the cytotoxicity and bioactivity of hydraulic calcium silicate cements used as root-end filling materials. <br>Methods <br>A literature search strategy was carried out on PubMed. Studies published in English between January 1993 and May 2023, focused on commercial hydraulic cements used as root-end filling materials, were selected. Review papers, clinical trials, case report, case series and animal studies were excluded. This screening was conducted by three researchers independently. <br>Results <br>In total, 27 cellular studies were included in this scoping review. Established cell lines including mouse osteoblastic cell line, murine fibroblast cell lines, murine macrophage cell line, human osteosarcoma cell lines were used in 11 studies. Primary cells including human periodontal ligament cells, gingival fibroblasts, osteoblasts, stem cells derived from apical papilla, bone marrow-derived mesenchymal stem cells, and inflammatory cells isolated from human periapical lesions were selected in 16 studies. For cement preparation, 18 studies tested set hydraulic cements (varied between 2 hours to 2 weeks), 4 studies evaluated freshly mixed non-set cements, and 5 studies included both set and no-set cements. For the exposure of hydraulic cements to cells, 7 studies seeded the cells on top of cement disks (direct contact), 19 studies used cement extracts (indirect contact), and 1 study included both direct and indirect contacts. The ratio of cell counts to the cement amount or the concentration of cement extracts varied largely among studies. Apart from cytotoxicity, inflammatory and osteogenic/odontoblastic differentiation responses of cells were assessed. <br>Conclusions <br>There is a lack of standardized tests for evaluating the cytotoxicity and bioactivity of root-end filling materials. To facilitate the comparisons across different laboratories and studies, and to enhance the clinical value of <em>in vitro</em> laboratory testing, the development of a standardized, reproducible, and clinically relevant method is highly desirable and essential. <br></p>