Systematic investigation of β-dicalcium silicate-based bone cements in vitro and in vivo in comparison with clinically applied calcium phosphate cement and Bio-Oss®

Abstract

Ca-silicate cements have drawn considerable attention for their potential applications in the field of bone repair due to their excellent bioactivity in vitro. Significant progress with regard to physicochemical properties and optimization of fabrication techniques of this new cement system has been achieved. However, it is unknown whether these so-called bioactive cements could efficiently repair critical-size bone defects in vivo. Herein we systematically investigated the biological performance of a β-dicalcium silicate (β-C₂S)-based bone cement in comparison with the clinically used calcium phosphate cement (CPC) and Bio-Oss®. The results indicated that β-C₂S-based cement with 25% gypsum exhibited appreciable Ca and Si release and weight loss (∼28%) in Tris buffer within the initial 7 d but then maintained a mild degradation rate during 1–4 weeks. Also, the β-C₂S-based cement extracts readily enhanced MC3T3 proliferation at a 25 mg ml⁻¹ level at 4 d and ALP expression at 50–100 mg ml⁻¹ levels at 7 d. For the β-C₂S-based group, increased mRNA levels of osteogenic genes, including Collagen I, osteocalcin, special protein 7, and runt-related transcription factor 2, were observed. In particular, histological staining and microCT reconstruction analyses demonstrated that this new cement could significantly enhance new bone regeneration in a critical-sized skull defect model in rabbits compared with CPC and Bio-Oss®. These findings suggest that β-C₂S-based biocement is a promising bone implant for bone regeneration and repair due to its excellent biological performance in vitro and in vivo.