Appreciable biosafety, biocompatibility and osteogenic capability of 3D printed nonstoichiometric wollastonite scaffolds favorable for clinical translation

Alveolar bone destruction due to periodontal disease often requires a bone graft substitute to reconstruct the anatomical structures and biological functions of the bone tissue. Despite significant advances in the development of foreign ion-doped nonstoichiometric wollastonite bioceramics (CaSiO3, nCSi) for alveolar bone regeneration over the past decade, the in vivo biosafety and osteogenesis of nCSi scaffolds remain uncertain. In this study, we developed a customized porous nCSi scaffold to investigate the in vivo biocompatibility and osteogenic properties of nCSi bioceramics. Six percent Mg-doped nCSi bioceramic scaffolds were fabricated by digital light processing (DLP), and the scaffold morphology, pore architecture, compressive strength, in vitro biodegradation, and apatite-forming ability of the bioceramic scaffolds were investigated systematically. Subsequently, an alveolar bone defect rabbit model was used to evaluate the biocompatibility and osteogenic efficacy of the nCSi bioceramics. Animal weight, hematological test, blood biochemical test, wet weight of the main organs, and pathological examination of the main organs were conducted. Micro-CT and histological staining were performed to analyze the osteogenic potential of the personalized bioceramic scaffolds. The nCSi scaffolds exhibited appreciable initial compressive strength (>30 MPa) and mild mechanical decay over time during in vitro biodissolution. In addition, the scaffolds induced apatite remineralization in SBF. Bioceramic scaffolds have been proven to have good biocompatibility in vivo after implantation into the alveolar bone defect of rabbits. No significant effects on the hematological indices, blood biochemical parameters, organ wet weight, or organ histopathology were detected from 3 to 180 days postoperatively. The porous scaffolds exhibited strong bone regeneration capability in the alveolar bone defect model of rabbits. Micro-CT and histological examination showed effective maintenance of bone morphology in the bioceramic scaffold group; however, depressed bone tissue was observed in the control group. Our results suggest that personalized nCSi bioceramic scaffolds can be fabricated using the DLP technique. These newly developed strong bioceramic scaffolds exhibit good biocompatibility and osteogenic capability in vivo and have excellent potential as next-generation oral implants. Tissue-engineered strategies for alveolar bone repair require a bone graft substitute with appre