Morphological evaluation during in vitro chondrogenesis of dental pulp stromal cells

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.

Biocompatibility of bioaggregate cement on human pulp and periodontal ligament (PDL) derived cells / 대한치과보존학회지

OBJECTIVES: This study was performed to investigate the biocompatibility of newly introduced Bioaggregate on human pulp and PDL cells. MATERIALS AND METHODS: Cells were collected from human pulp and PDL tissue of extracted premolars. Cell culture plate was coated either with Bioaggregate or white MTA, then the same number of cells were poured to cell culture dishes. Cell attachment and growth was examined under a phase microscope after 1,3 and 7 days of seeding. Cell viability was measured and the data was analyzed using Student t-test and one way ANOVA. RESULTS: Both types of cells used in this study were well attached and grew healthy on Bioaggregate and MTA coated culture dishes. No cell inhibition zone was observed in Bioaggregate group. There was no statistical difference of viable cells between bioaggreagte and MTA groups. CONCLUSIONS: Bioaggregate appeared to be biocompatible compared with white MTA on human pulp and PDL cells.