Stainless steel is used for various medical devices. Titanium is also widely used because of its tight bonding to bone tissue, namely osseointegration. The aim of the present study was to investigate the efficacy of three-dimensional stainless steel and titanium porous structure scaffolds by in vitro and in vivo experiments. Stainless steel and titanium fiber materials were designed as non-degradable metallic three-dimensional scaffolds with a three-dimensional porous structure for bone reconstruction. In one in vitro experiment, stainless steel and titanium disks were immersed in simulated body fluid. After immersion, a greater amount of hydroxyapatite precipitation was observed on titanium disks than on stainless steel disks. The crystallographic structure of precipitated hydroxyapatite was confirmed by the measurement of X-ray diffraction patterns. In another in vitro study, the adsorption behavior of fibronectin to stainless steel and titanium was monitored by the quartz crystal microbalance (QCM) method, which demonstrated more fibronectin adsorption onto titanium than onto stainless steel. In an in vivo experiment, three-dimensional stainless steel or titanium fibers were implanted into the cortical bone of the tibia of rabbits. Histological and histomorphometrical evaluation revealed a significantly greater amount of bone formation inside the porous area of the titanium fibers after 4 weeks of implantation. The present study also revealed better osteoconductivity of titanium than stainless steel. It is presumed that this was due to the differences in the characteristics of passive film between titanium and stainless steel. Titanium fibers are expected to be useful as a non-resorbable three-dimensional scaffold in bone reconstruction.
Bone remodeling is achieved through the resorptive activity of osteoclasts and the synthetic activity of osteoblast and it continues throughout life. Cement lines are formed by osteoblasts and are recognized between old and new bone. However, the detailed structure of cement lines has still not been clarified. The present study researched the ultrastructure of cement lines in a ferret femur using light microscopy (LM), transmission electron microscopy (TEM) and scanning electron microscopy (SEM). On LM, many resorption tunnels were recognized in cortical bones. Some osteoclasts in Howship's lacunae were observed at the top of the resorption tunnel (cutting cone), and osteoblasts forming some layers were recognized behind osteoclasts (filling cone). The layer of osteoid was observed under osteoblasts, and it was slightly eosinophilic on the decalcified specimen. A very thin layer of cement lines was recognized between osteoid and old bone, and it was slightly basophilic on hematoxylin and eosin (HE). On the non-decalcified sections stained with toluidine blue (TB), cement lines showed anochromasia in the non-etched specimen, but stained with TB in the etched one. On TEM, cement lines were recognized between osteoid and old bone, and they were revealed as extracellular matrices of an afibrillar layer, with a thickness of about 2µm. On BSE analysis, cement lines of osteon were observed as 1-2µm white lines. Conclusively, the present study indicated that cement lines are extracellular matrices of hypercalcified afibrillar layer having 2µm thickness.
Ameloblastoma is a slow-developing benign odontogenic tumor, but it has relatively large number of local recurrence. Ameloblastoma was classified on the basis of the morphology that predominates in the tumor itself into plexiform type, follicular type, and other subtypes, and there have been comparative histological and clinical studies that include prognosis predictions for the different types. However, there are no conclusions regarding histological patterns and tumor activities have been reached.The purpose of the present study was to perform a detailed investigation of the progressive front of solid/multicystic type ameloblastoma in order to search for possible prognostic factors.For this study, 22 cases were chosen, in whom solid/multicystic type of a ameloblastoma.Progressive fronts of the solid/multicystic type ameloblastoma were morphologically classified into six types; plexiform, follicular, basaloid cell, sheet, trabecular and polycystic types, and immunohistochemical and morphometrical comparative studies were performed.Proliferative activity of columnar cells was highest in basaloid cell type at 1.9%. Periostin showed moderate to strong positive reaction in columnar cells of plexiform and basaloid cell types. Columnar and stellate-reticulum-like cells of basaloid cell type showed strong positive reaction for VEGF. The highest microvessel density and microvessel area using CD105 in basaloid cell type were 48.2±24.2 and 11.4±8.6%, respectively.The result of this study suggested with resection of solid/multicystic type ameloblastoma, it is important the prognosis observation to base judgment on the morphology of cells in the progressive front or in the vicinity of the resected surface.
Raman spectroscopy is based on Raman scattering of light form molecules, and Raman spectra provide highly useful information about molecular composition and its circumstances. The micro FT-Raman spectra both of ghost cells in calcifying cystic odontogenic tumor and keratinocytes of the gingiva showed a broad beak centered around 850 cm -1 .
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