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Periodontal diseases result from inflammation by bacterial infection in plaques, leading to tooth loss. However, regenerative approaches with periodontal tissue regeneration by guided tissue regeneration and enamel matrix derivative are not yet well established. Tissue regeneration requires three factors: cells, scaffold, and growth factors. Dedifferentiated fat cells (DFATs) are pluripotent with the same differentiation capacities as mesenchymal stem cells (MSCs). Access to MSCs is limited, whereas donor cells for DFATs are abundant in adipose tissues and can be non-invasively obtained. Therefore, we tested DFATs as a new source for periodontal tissue regeneration in an experimental periodontal tissue loss model in rats by transplanting DFATs on an atelocollagen scaffold using DFATs isolated from Sprague-Dawley (SD) rats expressing green fluorescent protein (GFP). GFP-DFAT cells were transplanted on the palatal side of the upper left first molar in SD rats and detected by H&E staining, GFP, and proliferating cell nuclear antigen (PCNA) expression. DFAT differentiation was also evaluated in three-dimensional cultures. GFP positive cells were detected in the regenerated tissue by the DFATs/scaffold mixture at 4 weeks after transplantation, and PCNA-positive cells were significantly increased in the periodontal ligament along the new bone in the DFATs/scaffold group more than in the scaffold-only group, suggesting that DFATs differentiate in the same manner as MSCs and regenerate in the defective areas. Consistent with previous reports, DFATs differentiation was slower than that with stem cells. The present study demonstrates that DFATs are pluripotent and an effective new source of cells for periodontal tissue regeneration.

No abstract

：The purpose of this study was to analyze the plaque removal efficacy of a sonic-powered toothbrush which is capable of applying brushing pressure at a certain frequency, that would produce mechanical resonance. We studied the factors which may improve the cleaning efficacy, such as the operational frequency and brushing pressure of such toothbrushes. We focused on two specific operational frequencies (High speed/Low speed) which would cause mechanical resonance, and used another frequency (Intermediate speed) which would not cause mechanical resonance as reference. We evaluated these factors using our brushing machine, and evaluated the cleaning efficacy by measuring the percent removal of artificial plaques in a dental model via imaging analysis. The results revealed that under the brushing pressure of 100gf, the efficiency of plaque removal was in the order, from the highest to the lowest, of High speed, Low speed and Intermediate speed. Operating the toothbrush at a certain speed causing mechanical resonance would enlarge the amplitude of the vibration, so that the plaque removal efficiency would be greater at the Low speed than at the Intermediate speed. On the other