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Morphological evaluation during in vitro chondrogenesis of dental pulp stromal cells
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Choo-Ryung Chung, Ha-Na Kim, Yeul Park, Min-Jeong Kim, Young-Ju Oh, Su-Jung Shin, Yoon-Jeong Choi, Kyung-Ho Kim
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Restor Dent Endod 2012;37(1):34-40. Published online March 2, 2012
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DOI: https://doi.org/10.5395/rde.2012.37.1.34
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 Abstract
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Objectives
The aim was to confirm the stem cell-like properties of the dental pulp stromal cells and to evaluate the morphologic changes during in vitro chondrogenesis.
Materials and Methods
Stromal cells were outgrown from the dental pulp tissue of the premolars. Surface markers were investigated and cell proliferation rate was compared to other mesenchymal stem cells. Multipotency of the pulp cells was confirmed by inducing osteogenesis, adipogenesis and chondrogenesis. The morphologic changes in the chondrogenic pellet during the 21 day of induction were evaluated under light microscope and transmission electron microscope. TUNEL assay was used to evaluate apoptosis within the chondrogenic pellets.
Results
Pulp cells were CD90, 105 positive and CD31, 34 negative. They showed similar proliferation rate to other stem cells. Pulp cells differentiated to osteogenic, adipogenic and chondrogenic tissues. During chondrogenesis, 3-dimensional pellet was created with multi-layers, hypertrophic chondrocyte-like cells and cartilage-like extracellular matrix. However, cell morphology became irregular and apoptotic cells were increased after 7 day of chondrogenic induction.
Conclusions
Pulp cells indicated mesenchymal stem cell-like characteristics. During the in vitro chondrogenesis, cellular activity was superior during the earlier phase (within 7 day) of differentiation.
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Surface roughness and microleakage of class V composite restorations : Effect of surface sealing
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Min-Jeong Kim, Mi-Jeong Lee, Mi-Kyung Yu, Soo-Joung Park, Kwang-Won Lee
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J Korean Acad Conserv Dent 2005;30(1):22-30. Published online January 31, 2005
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DOI: https://doi.org/10.5395/JKACD.2005.30.1.022
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Abstract
PDFPubReaderePub
The purpose of this study was to compare the effect of surface sealing materials on microleakage and surface roughness in Class V composite restorations.
Twenty five standardized Class V cavity preparations were made on the facial surface of human premolars and were randomly assigned to 5 groups. The teeth were restored with Z-250 after applying Single Bond. Following 7 days storage in distilled water at 37℃, the restorations were sealed as following systems : No sealing ; Single Bond Adhesive ; Biscover ; Fortify ; Optiguard. Then, toothbrush abrasion test was conducted using a wear testing machine.
Surface roughness was measured by means of profilometer before and after toothbrushing and the results were statistically analysed by using a paired t-test and ANOVA. The bonded interfaces and the changes of surface roughness were examined by SEM.
For microleakage test, specimens were stained in a 2% methylene blue solution, then longitudinally sectioned and analyzed for leakage at occlusal and cervical interfaces using stereomicroscope. The results were statistically analysed by using a Kruskal-Wallis and Mann-Whitney U test.
Surface roughness was increasing in all groups after toothbrushing, but no statistically significant differences. In SEM observation, surface sealant was partially retained and partially detached in bonded interfaces. Especially, microgap was identified in cervical margins. In microleakage test, there was better seal in the enamel region and a significant difference between groups at occlusal margin. Control group and Single Bond group had significantly better marginal seal at enamel margin than cervical margin.
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KACD
