The in vitro and in vivo cementogenesis of CaMgSi₂O₆ bioceramic scaffolds.

The goal of periodontal tissue engineering is to regenerate alveolar bone, root cementum and periodontal ligament. To achieve this goal, bioactive scaffolds play an important role in inducing in vitro osteogenic/cementogenic gene expression of periodontal ligament cells (PDLCs) and in vivo bone/cementum formation. Diopside (DIOP: CaMgSi2O6) ceramics have shown excellent in vitro bioactivity for potential bone repair application. However, there is no study about DIOP porous scaffolds for periodontal tissue engineering. The aim of this study is to prepare DIOP scaffolds and investigate their in vitro and in vivo osteogenesis/cementogenesis for periodontal regeneration application. DIOP scaffolds with highly porous architecture were prepared and β-tricalcium phosphate (β-TCP) scaffolds were used for the control. The interaction of DIOP scaffolds with PDLCs was studied by investigating cell attachment, proliferation and ostegenic/cementogenic differentiation of PDLCs. DIOP scaffolds were implanted into the periodontal defects of beagle dogs to evaluate their in vivo osteogenesis/cementogenesis by hematoxylin and eosin (H&E), tartrate-resistant acid phosphatase staining, and immunohistochemistry (type I collagen: Col I; cementum attachment protein) analyses. The results have shown that DIOP scaffolds supported the attachment and proliferation of PDLCs. DIOP scaffolds significantly enhanced osteogenesis/cementogenesis-related gene expression (Col 1, Runx2, transforming growth factor beta 1, and bone morphogenetic protein 2) of PDLCs, compared to β-TCP scaffolds. The in vivo study showed that DIOP scaffolds induced new bone and cementum regeneration of periodontal tissue defects. The rate of new bone and cementum in DIOP scaffolds is comparable to that in conventional β-TCP scaffolds. Our results indicated that silicate-based DIOP ceramics could not only be used for bone tissue engineering, but also for periodontal tissue engineering due to their excellent in vitro and in vivo osteogeneis/cementogenesis.