The aim of this study is to investigate the role of hydroxyapatite (HAp) in novel apatite ionomer cement (AIC), an improved glass ionomer cement (GIC) that contains porous HAp. AIC samples were prepared using the latest conventional GIC, Fuji IX GP ExtraTM, with porous and spherical HAp (HApS), and were subjected to mechanical strength measurements, fluoride release test, scanning electron microscopy observations and multi-mineral release test, and were compared with IX-Ex, Fuji IX GPTM (IX-GP) and S-PRG filler containing composite resin, Beautifil IITM (GIOMER). The flexural strength and fluoride release properties of AIC were significantly higher than those of IX-Ex. The release of fluoride, aluminum, silicon and phosphorus from AIC specimens was greater when compared with IX-Ex and GIOMER. Therefore, porous HAp improves both the strength and bioactive functions of GIC without losing the advantages of conventional GIC.
The titanium oxide nanotube (TNT) is a novel high-functional material with photocatalytic performance inherent to titanium oxide improved by combining the diverse properties of the specific nanotube structure and titanium oxide crystal. Basic research was conducted on TNT for its application as a dental bleaching agent.TNT was chemically synthesized, and the amount of generated radicals was determined by the ESR method. In addition, the oxidation-reduction reaction on UV irradiation was investigated using methylene blue to examine photocatalytic properties. As a result, TNT generated a larger amount of radicals than TiO2, and showed improved photocatalytic properties. Furthermore, a bleaching experiment was conducted using a colored enamel model. Then, sufficient bleaching effects were demonstrated with visible light, suggesting the potential application of TNT to dental bleaching.
The purpose of this study was to track the fate of GFP-labeled transgenic mouse mesenchymal stem cells (MSC) transplanted in nude mice. Mouse MSC had been collected from tibia of whole body GFP-labeled mice; were transplanted into five nude mice by tail vein injection; and were fed for 4 weeks. After comfort sacrifice, the existence and accumulation of GFP-labeled mouse MSC transplanted in nude mice was examined by in Vivo Florescence imaging. The searched cells were absent in bone marrow regions in dissected long bones (femurs). On the contrary, exposed abdominal cavities revealed that one out of five mice had a small fluorescent node on the liver surface. This means that at 20% probability, transplanted GFP-labeled mouse MSC could circulate in the vein, and settle and multiply in the terminal organ of a host mouse. This finding appears to contribute to future stem cell therapy by homing phenomenon of MSC.
The effects of nanomaterials on human reproduction and development remain unclear. Thus, their embryotoxicity should be examined to ensure the biological safety of the next generation. In the present study, the effects of C60 fullerene on cell differentiation were investigated using EL-M3 and ES-R1-EGFP B2/EGFP cell lines that require feeder cells, instead of the ES-D3 cells used for the EST method, an in vitro embryotoxicity test. As a result, the effects of C60 fullerene on cell differentiation increased in a concentration-dependent manner for both cell lines, demonstrating the absence of severe developmental toxicity. The developmental toxicity of C60 fullerene should be investigated for applications to new drugs.
Angiogenesis is quite important for bone tissue regeneration, because formed blood vessel in bone supply oxygen and nutrients to osteoblasts to be differentiated to form new bone. In particular, cultured bone implantation using porous ceramics scaffolds, a kind of bone tissue engineering, needs enough blood vessel formation into central porous area, maintaining osteoblast activities. This is a report successfully inducing bone formation and showing our application of adenoviral vector carrying angiogenic factor VEGF(vascular endothelial growth factor) for activating osteoblasts to transduce MSCs (messenchymal stromal cells) in a cultured bone transplantation model. For this purpose, we constructed the recombinant adenoviral vector carrying VEGF cDNA (Adv-VEGF) and the Adv-VEGF infected MSCs derived osteoblasts/porous ceramic scaffold composite was implanted into subcutaneous sites and orthotropic sites of Fischer rats. In the rat bone defect model, much blood formation were observed at 10 days postimplantation, in addition to the induction of bone formation by virus infection. TRAP positive osteoclasts and invasion of bone marrow tissues were observed in the transplanted ceramics showing the remodeling of implanted ceramics. Overexpression of VEGF proved to be effective in inducing bone formation with remodeling in a cultured bone transplantation model.
Many research institutions for the basic technical development of regenerative medicine are investigating human iPS cells competitively. In the present study, technical objectives for this purpose are summarized. The teeth and oral cavity have been repaired and functionally augmented by prosthetic materials since ancient times in the field of dentistry. This is explained by the fact that artificial materials have been specifically developed in dentistry, and such materials have played more important roles in dentistry than in other medical fields. In the present study, technical objectives for this purpose are summarized. Also, the uniqueness of regenerative medicine in dentistry is described.