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加熱処理が球状ハイドロキシアパタイトの骨欠損部での骨伝導能に与える影響
Get PDFapplication/pdfHydroxyapatite (HAP) shows different characteristics depending on the sintering temperature. However, the effects of the heat treatments on bone formation ability in bone defects have not been well elucidated. To develop bone filling materials having higher tissue affinity and superior bone conductivity, we attempt in this study to clarify the histological processes of osteosynthesis and osteogenesis in response to various heat-treated spherical HAP particles filled in bone defects. Spherical-shaped HAP particles (ca/p of more than 1.7) were heat-treated at 800℃ and 900℃ for 60 and 1440 minutes. Each HAP particle was examined in bone defects (diameter 3mm) surgically created in the calvaria of male rats. Demineralized sections were made and observed by light microscopy. Some non-demineralized specimens were examined by scanning electron microscopy. At 7 days after implantation, new bone formation occurred from the surface of bone defected cavity in all experimental groups. At 14 days, newly formed bone was observed only around the HAP particles heat-treated at 800℃ for 1440 minutes (the 800/1440 group). Bone formation of the 800/1440 groups was more rapid than in the other experimental groups. Furthermore, in the 800/1440 group, the number of TRAP positive multinucleated cells (osteoclast-like cells) resorbing HAP particles was much greater than that in other experimental groups throughout the experimental period. These results demonstrate that 800/1440 HAP particles have superior osteoconductivity and bioresorbability and suggest they may be useful as a filling material for bone defects.journal articl
破骨細胞の神秘
Get PDFapplication/pdfDeficiency of osteoprotegerin (OPG), a soluble decoy receptor for the receptor activator of NF-kB ligand (RANKL), in mice induces osteoporosis caused by enhanced bone resorption, but also accelerates bone formation. We examined whether bone formation is coupled with bone resorption in OPG-deficient (OPG^) mice delete using risedronate, an inhibitor of bone resorption. Histomorphometric analysis showed that bone formation-related parameters (e.g., mineral apposition rate and osteoblast surface/bone surface) in OPG^ mice sharply decreased with suppression of bone resorption by daily injection of risedronate for 30 days. OPG^ mice exhibited high serum alkaline phosphatase activity and osteocalcin concentration, both of which were decreased to the levels of wild-type mice by the risedronate injection. Serum levels of RANKL were markedly elevated in the OPG^ mice, but were unaffected by risedronate. These results suggest that bone formation is coupled with bone resorption at local sites in OPG^ mice, and that serum RANKL levels do not reflect this coupling.journal articl
歯科矯正治療により口唇部の前突感が良好に改善した上下顎前突の二症例
Get PDFapplication/pdfDentoalveolar bimaxillary protrusion is a quite common malocclusion in the Japanese population and has been accepted as a normal occlusion for a long time. Recently, not only correction of crowding teeth but also cosmetic concerns about protrusive lips due to dentoalveolar protrusion have increased under the circumstances of a more globally oriented Japanese society. The horizontal and vertical relationship between the upper incisors and lip is esthetically quite important, exclusively to young female patients. The frontal face may also be considered to require a good smile balance (line) on anterior teeth alignment, and a good upper lip contour, in orthodontic treatment outcomes. In this case report, four first bicuspid extractions were achieved and the results obtained satisfied the patients' main complaints of initial protrusive lips and difficulty in lip closing. The two cases were successfully treated with good posterior occlusion and an excellent profile, and are now in retention with removable retainers.journal articl
ホワイトニングの実際
Get PDFapplication/pdfIt is a universal hope to retain clean teeth and dentition as long as possible. The number of patients with chief complaints of tooth discoloration and staining, and inquiries about esthetics and whitening of the teeth, are increasing. Dental treatment is shifting from the previous age of tooth pain relief and removal to the age of emphasis on esthetic recovery of natural tooth color and morphology in addition to the recovery of functionality. Therefore, it is necessary for clinicians to try to meet these various requests by patients. Although bleaching, veneer restoration, and prosthetic treatment are used for tooth discoloration and staining, we reported the following items focusing on a bleaching method, and describe clinical cases in this paper: I. Causes of tooth discoloration and staining II. Indications and contraindications for bleaching III. Technical procedures for intra-oral examination IV. Bleaching of the vital teeth 1. Office bleaching method 2. Home bleaching method V. Bleaching of the pulpless tooth 1. Walking bleach technique 2. Bleaching of the pulpless tooth using Highlight^[○!R]journal articl
