Injectable strontium-containing tricalcium silicate biocements reinforced by nano HA/F127 hydrogel: Enhanced hydration kinetics, anti-washout, and dentinogenesis for vital pulp preservation

Preserving the vital pulp poses significant challenges in clinical pulp injury repair. Tricalcium silicate (C3S)-based cement has emerged as a successful pulp capping biomaterial. However, its efficacy in inducing pulp-dentin complex regeneration requires enhancement, and handling difficulties, poor anti-collapsible ability and inadequate self-setting performance remain significant obstacles, restricting its broader application in endodontics. In this study, a multifunctional SrCO 3 -doped C3S biocement (C3S-Sr/F127-nHA) reinforced by Pluronic® F127 thermoreversible hydrogel and nano hydroxyapatite (nHA) was developed to overcome the limitations of C3S-based cements. The thermoresponsive characteristic of F127 conferred the C3S pastes smart response behavior, allowing for optimal operability at room temperature and maintaining excellent anti-collapse properties at body temperature. C3S-Sr/F127-nHA exhibited an injectability rate of up to 93 %. nHA facilitated the hydration kinetics of C3S, resulting in reduced setting time and enhanced compressive strength. Furthermore, C3S-Sr/F127-nHA demonstrated excellent apatite mineralization ability, cytocompatibility, and potential for osteo/odontogenic induction. The inclusion of Sr 2+ ions and nHA promoted osteo/odontogenic differentiation of stem cells isolated from human exfoliated deciduous teeth (SHED). In vivo findings indicated that C3S-Sr/F127-nHA could stimulate the formation of a homogeneous dentin bridge. Consequently, C3S-Sr/F127-nHA is a promising biocement for use in regenerative endodontics.