Rational design and fabrication of a β-dicalcium silicate-based multifunctional cement with potential for root canal filling treatment.

The integration of physicochemical and biological performances in root canal treatment represents a challenge for long-time antileakage, antibacterial, and even inducing periradicular cementum/bone tissue regeneration. The objective of this work is to develop a β-Ca2SiO3 (β-C2Si)-based cement as a new root canal filler with good antibacterial ability, sealability and bioactivity. β-C2Si powders with controllable free CaO content were prepared by regulating the calcium/silicate molar ratio in reaction medium. It was demonstrated that a composite paste with 10-30 wt% α-gypsum at a liquid-to-powder ratio of 0.6 ml g-1 remained injectable for 12 min and provided a significant pH rise during setting. Notably, the hydraulic cements with high free CaO contents exhibited bactericidal or bacteriostatic properties against three bacterial strains, Streptococci mutans, Actinomyces naeslundii, and Actinomyces viscosus, which were demonstrated by the agar diffusion method. Also, the injected paste in root canal ex vivo showed extremely low microleakage of Rhodamine B but a good apatite-mineralization response. Therefore, these intrinsic antibacterial activity, bioactivity, injectability and tight adaption to root canal sealability make β-C2Si/α-gypsum composites preferential candidates for application in endodontics, such as root-end filling, pulp capping therapy, microleakage prevention, as well as for inducing hard tissue regeneration.