The effects of calcium silicate cement/fibroblast growth factor-2 composite on osteogenesis accelerator in human dental pulp cells

Baghdadite coating formed by hybrid water-stabilized plasma spray for bioceramic applications: Mechanical and biological evaluations

This work studies the mechanical and biological properties of Baghdadite (BAG, Ca₃ZrSi₂O₉) coating manufactured on Ti6Al4V substrates by hybrid water-stabilized plasma spray (WSP-H). Hydroxyapatite (HAp, Ca₁₀(PO₄)₆(OH)₂) coating was produced by gas-stabilized atmospheric plasma spray and used as a reference material. Upon spraying, the BAG coating exhibited lower crystallinity than the HAp coating. Mechanical testing demonstrated superior properties of the BAG coating: its higher hardness, elastic modulus as well as a better resistance to scratch and wear. In the cell viability study, the BAG coating presented better human osteoblast attachment and proliferation on the coating surface after three days and seven days compared to the HAp counterpart. Furthermore, the gene expression study of human osteoblasts indicated that the BAG coating surface showed higher expression levels of osteogenic genes than those on the HAp coating. Overall, this study indicates that enhanced mechanical and bioactive properties can be achieved for the BAG coating compared to the benchmark HAp coating. It is therefore concluded here that the BAG coating is a potential candidate for coating orthopedic implants.

Preparation of the fast setting and degrading Ca-Si-Mg cement with both odontogenesis and angiogenesis differentiation of human periodontal ligament cells

Develop a fast setting and controllable degrading magnesium-calcium silicate cement (Mg-CS) by sol-gel, and establish a mechanism using Mg ions to stimulate human periodontal ligament cells (hPDLs) are two purposes of this study. We have used the diametral tensile strength measurement to obtain the mechanical strength and stability of Mg-CS cement; in addition, the cement degradation properties is realized by measuring the releasing amount of Si and Mg ions in the simulated body fluid. The other cell characteristics of hPDLs, such as proliferation, differentiation and mineralization were examined while hPDLs were cultured on specimen surfaces. This study found out the degradation rate of Mg-CS cements depends on the Mg content in CS. Regarding in vitro bioactivity; the CS cements were covered with abundant clusters of apatite spherulites after immersion of 24h, while less apatite spherulites were formatted on the Mg-rich cement surfaces. In addition, the authors also explored the effects of Mg ions on the odontogenesis and angiogenesis differentiation of hPDLs in comparison with CS cement. The proliferation, alkaline phosphatase, odontogenesis-related genes (DSPP and DMP-1), and angiogenesis-related protein (vWF and ang-1) secretion of hPDLs were significantly stimulated when the Mg content of the specimen was increased. The results in this study suggest that Mg-CS materials with this modified composition could stimulate hPDLs behavior and can be good bioceramics for bone substitutes and hard tissue regeneration applications as they stimulate odontogenesis/angiogenesis.

Human Dental Pulp Cells Responses to Apatite Precipitation from Dicalcium Silicates

Unraveling the mechanisms behind the processes of cell attachment and the enhanced proliferation that occurs as a response to the presence of calcium silicate-based materials needs to be better understood so as to expand the applications of silicate-based materials. Ions in the environment may influence apatite precipitation and affect silicate ion release from silicate-based materials. Thus, the involvement of apatite precipitate in the regulation of cell behavior of human dental pulp cells (hDPCs) is also investigated in the present study, along with an investigation of the specific role of cell morphology and osteocalcin protein expression cultured on calcium silicate (CS) with different Dulbecco's modified Eagle's medium (DMEM). The microstructure and component of CS cement immersion in DMEM and P-free DMEM are analyzed. In addition, when hDPCs are cultured on CS with two DMEMs, we evaluate fibronectin (FN) and collagen type I (COL) secretion during the cell attachment stage. The facilitation of cell adhesion on CS has been confirmed and observed both by scanning with an electron microscope and using immunofluorescence imaging. The results indicate that CS is completely covered by an apatite layer with tiny spherical shapes on the surface in the DMEM, but not in the P-free DMEM. Compared to the P-free DMEM, the lower Ca ion in the DMEM may be attributed to the formation of the apatite on the surfaces of specimens as a result of consumption of the Ca ion from the DMEM. Similarly, the lower Si ion in the CS-soaked DMEM is attributed to the shielding effect of the apatite layer. The P-free DMEM group releases more Si ion increased COL and FN secretion, which promotes cell attachment more effectively than DMEM. This study provides new and important clues regarding the major effects of Si-induced cell behavior as well as the precipitated apatite-inhibited hDPC behavior on these materials.

Stimulatory effects of the fast setting and suitable degrading Ca–Si–Mg cement on both cementogenesis and angiogenesis differentiation of human periodontal ligament cells

The purpose of this study is to develop a fast setting and suitable degrading Mg–calcium silicate cement (Mg–CS) and a mechanism using Mg ions to stimulate human periodontal ligament cells (hPDLCs).