In this study, two different proteins, fibronectin (FN) or albumin (Alb), were immobilized onto poly (lactic acid-ε-caprolactone) (PLCL) films. FN is a cell adhesion protein, whereas Alb is a cell adhesion-inhibiting protein.The amount of immobilized FN on the PLCL film was significantly greater than that for Alb (p < 0.05). The number of MC3T3-E1 cells that adhered to FN-PLCL films was larger than that for Alb-PLCL films (p < 0.05) in a 90-min cell assay. After 3 days of culture, cells appeared more flattened on FN-PLCL films, and small lamellipodia and filopodia were observed. These results indicate that FN and Alb-immobilized onto PLCL films retained their cell adhesion-promoting and cell adhesion-inhibiting properties, respectively.
The purpose of this study was to investigate the effect of colloidal platinum nanoparticles on dentin bond strength. One bonding system was tested CLEARFIL Universal Bond (CUB) and tested following two kinds as a surface treatment agent: 1 K ETCHANT Syringe (Ech), 2 the thing which mixed with phosphoric acid by a colloidal platinum nanoparticles (CPN). Dentin surfaces were subjected to one of the following treatments: NE(only CUB), E(Ech and CUB), CPN-E(CPN and CUB). After resin composite build-up, each specimen was sectioned after water storage at 37°C for 24 hours to obtain beams with a bonded area of 1 mm2. µTBS test was performed using half of the beams from each group. Rest of the beams were tested after 6 months. The bond strength did not decrease only CPN-E in six months later. This study indicated that adhesion long-term durability is provided when use CUB and CPN together.
The purpose of this study was to evaluate the microtensile bond strength (μTBS) of an experimental universal adhesive, K5D-01 (K5D, Tokuyama Dental) to dentin and to observe the interfacial micromorphology. K5D is a universal adhesive without the light irradiation during the application process. K5D can be used for various clinical applications such as bonding agents for resin composite, surface treatment agents for resin core materials or resin cements. Scotchbond Universal Adhesive (SBU, 3M ESPE) used as a control material. Flat dentin surfaces of human molars were exposed using #600 SiC paper and bonded with the respective adhesive of each system. After bonding, various resin were built up on the surfaces and cured under two conditions: light condition or dark condition. Dark curing negatively affected the bond strength of SBU. The newly developed universal adhesive K5D-01 was not affected by the curing conditions.
Placing a ligature around the mouse molar have been widely used in experimental periodontitis to investigate disease mechanisms and novel treatments. However, the period of ligation was different in the previous studies: From 1 week to 3 weeks. The aim of the present study is to verify the proper period of ligation to induce periodontitis in mice. The ligature was placed around the upper second molars of 18 male C57BL/6 mice, 8 weeks old, and the animals were sacrificed at 1 and 3 weeks. Then, the maxillae were analyzed with micro-computed tomography. The amount of alveolar bone loss at 1 week was statistically similar to the one at 3 weeks. The present results suggested that the ligation for 1 week is enough to induce periodontitis in mice.
Developmental toxicity of chemical substances seriously impairs normal birth of human newborns. Corrosion resistance of titanium used in implant fixtures extremely decreases in the presence of fluorine ion produced by acidification. To our knowledge, cytotoxicity and developmental toxicity of corrosion products formed by corrosion of the titanium surface by fluoride have not been reported. Thus, we investigated differentiation and proliferation of ES-D3 cells, which is a parameter employed in the EST method. When the surfaces of JIS Class 1 and 2 titanium plates were corroded with hydrofluoric acid solution, cell differentiation and proliferation were affected. It was clarified that although this finding does not directly lead to clinical developmental toxicity, it is also necessary to investigate corrosion of titanium alloys used in implant fixtures.
In regenerative dental therapy, the development of bone scaffold materials to enable augmentation of bone for dental implant and prosthesis treatment is important. Montipora digitata exoskeleton-derived aragonite particles are porous, bioresorbable bone scaffold and applied to bone defects as natural materials. In this bone scaffold material, it is necessary to form collagen fibers which are the extracellular matrix of particles derived from Montipora digitata skeleton capillary vessels and newly formed bone. Therefore, we cultured fibroblast cells and added the particles in order to investigate the effect of cell proliferation ability and production of collagen fibers. In this study, it was observed that cultured fibroblasts were enhanced cell proliferation and collagen fiber production by adding aragonite particles.
We formed collagen/porous-HAP composite (Col/p-HAP) and collagen control (Col) specimens using freeze-drying technique and de-hydrothermal heat treatment. Critical-size bone defects (6 mm) were generated in the cranial bones of twelve 10-week-old Wistar rats, in which Col/p-HAP and Col specimens were implanted. After feeding for 4 weeks or 8 weeks, the rats were sacrificed (n=6 each), followed by micro-CT and histological analyses. Micro-CT revealed that the defect zones implanted with Col/p-HAP became significantly X-ray opaque with time whereas those with Col did not. Histological observations revealed that Col/p-HAP became considerably fragmented, exerting osteo-conductive effects in the defect zone at 8 weeks whereas Col was little osteo-conductive. Double staining showed dynamic new bone formation near p-HAP digested by nuclear cells in the defect zone. Col/p-HAP appears to be a useful new bone substitute material that is applicable to dental implantology.