Regeneration of periodontal ligaments in jawbone using materials driven by magnetic field

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The aim of this study was to construct the connective structure of hard tissue by fibrous ligaments in dynamic environment. For the development of the medical appliance, we selected elemental components and aligned the amplitude and frequency of magnetic materials reacting to magnetic gradient. We used the mixture materials of epoxy resin and magnetic substance metals (cobalt ferrite powder). In experiment of subcutaneous implantation, the biocompatibility of this material was confirmed histopathologically and physically. The healing of bone groove in rat cranium was investigated in static and dynamic states. The grooves of about 0.5, 1.0, and 1.5 mm breadth through the dura mater were formed in rat cranium. Histological sections were histologically observed. The groove of 1.5 mm breadth was connected with fibrous connective tissue. The groove of 1.0 mm breadth was reconstructed by bone tissue. Subsequently, the isolated bone surrounded by groove of 1.0 mm breadth, which will come under the dynamic influence of blood pressure in cranial cavity, showed no bony connection. In a part, the Sharpey's fibers, which reveal collagen fibers or bundles embedded in calcified tissue, were seen on the isolated and the surrounding bone surfaces. It was suggested that the Sharpey's fibers were formed by dynamic effects. To confirm the formation of Sharpey's fiber structure in tooth socket of jawbone, sintered tooth was implanted in first molar tooth socket in rat maxilla. Implanted teeth were extracted from else rats, and sintered in 1100℃, and sterilized. First molar tooth was extracted. And soon sintered tooth was implanted in extracted tooth socket. Sintered tooth was connected to second molar with resin. Granulation and fibrous connective tissue with slight inflammatory cells infiltration was present between sintered bone and alveolar bone on 10 days after implantation. It was suggested that the long-term observation is necessary.