Bioactivity and Regenerative Potential of Calcium Silicate-Based Endodontic Sealers on Human Periodontal Ligament Stem Cells: A Systematic Review of In Vitro Cellular Mechanisms.

Calcium silicate-based endodontic sealers are bioactive obturation materials that may support periapical regeneration, yet in vitro evidence remains fragmented and methodologically heterogeneous. This review evaluated whether these sealers show consistent cellular bioactivity in human periodontal ligament stem cells (hPDLSCs) and which outcomes and formulations show the most favourable regenerative potential. The review followed a predefined methodology informed by the Cochrane Handbook and was reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020. PubMed/MEDLINE, Scopus, Web of Science, the Cochrane Central Register of Controlled Trials, and Google Scholar were searched using Population, Intervention, Comparison, Outcomes, and Study design-based strategies. Risk of bias was assessed with the National Toxicology Program - Office of Health Assessment and Translation (NTP-OHAT) tool. Because materials, extract dilutions, exposure periods, assay protocols, and effect measures varied substantially, a structured narrative synthesis was undertaken instead of meta-analysis. Of 891 records, 15 studies met the eligibility criteria. Most used primary hPDLSCs characterised by mesenchymal stem-cell markers and compared calcium silicate-based sealers, including TotalFill BC Sealer (FKG Dentaire Sàrl, Le Crêt-du-Locle, Switzerland)/EndoSequence BC Sealer (Brasseler U.S.A. Dental, LLC, Savannah, Georgia, USA), BioRoot RCS (Septodont, Saint-Maur-des-Fossés, France), CeraSeal (Meta Biomed Co., Ltd., Cheongju, Republic of Korea), Bio-C Sealer (Angelus, Londrina, Brazil), Well-Root ST (VERICOM Co., Ltd., Chuncheon, Republic of Korea), and NeoSEALER Flo (Avalon Biomed, Houston, Texas, USA), with epoxy resin-based sealers, predominantly AH Plus (Dentsply DeTrey GmbH, Konstanz, Germany). Overall risk of bias was low, although blinding of outcome assessment was often unclear. Across 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and CCK-8 assays, calcium silicate-based sealers generally maintained or increased cellular metabolic activity, whereas AH Plus showed lower activity; NeoSEALER Flo and EndoSeal MTA (Maruchi, Wonju, Republic of Korea) showed less favourable or intermediate responses. Twelve scratch-wound studies reported migration comparable with or greater than controls; eleven Alizarin Red S studies reported increased mineral deposition, most pronounced for TotalFill BC Sealer/EndoSequence BC Sealer and BioRoot RCS; and eleven reverse transcription quantitative polymerase chain reaction (RT-qPCR) studies reported upregulation of osteogenic and cementogenic markers, including ALP, RUNX2, CEMP1, and CAP. Six studies assessed inflammatory or immunomodulatory responses; most reported lower pro-inflammatory cytokine expression, particularly IL-6 and IL-8, with calcium silicate-based sealers than with AH Plus, although responses varied by formulation and exposure time. Within the limits of two-dimensional models and heterogeneous protocols, contemporary calcium silicate-based root canal sealers appear more cytocompatible and biologically active toward hPDLSCs than conventional epoxy resin sealers, supporting favourable cellular metabolic activity, migration, mineralisation, and osteogenic and cementogenic differentiation. This review assessed whether calcium silicate-based sealers are cytocompatible and promote regenerative bioactivity in hPDLSCs.