An injectable tricalcium silicate/α-tricalcium phosphate/hydroxypropyl methylcellulose biocomposite with improved physicochemical properties and osteoinductive activity for endodontic application.

Tricalcium silicate (TCS)-based bioactive cements have attracted great attention for various endodontic applications owing to their hydraulic property, sealing ability and biological properties. Nevertheless, poor handling property and anti-washout ability are the main challenges for traditional TCS-based cements and their osteoinductive capacity needs enhance for accelerated pulpal and periapical tissue repair/regeneration. Herein, we developed an injectable TCS/α-tricalcium phosphate (α-TCP)/hydroxypropyl methylcellulose (HPMC) biocomposite with improved physicochemical properties and osteoinductive ability via the incorporation of α-TCP/HPMC. HPMC endowed TCS/α-TCP cements excellent injectablity (above 93 %) and anti-washout property. The introduction of 10 wt% α-TCP shortened the setting time of cements and obtained high compressive strength while an excess quantity of α-TCP could compromise its setting property. TCS/α-TCP/HPMC cements had good apatite formation ability and dentin interface adhesion. Moreover, TCS/10α-TCP/HPMC could significantly enhance cell viability and osteogenic differentiation of osteoblasts by increasing alkaline phosphatase (ALP) activity, collagen secretion, and extracellular matrix (ECM) mineralization and up-regulating the osteogenesis-related proteins and gene expression. These results indicated that the injectable TCS/10α-TCP/HPMC biocomposite is a promising candidate for endodontic uses.