Dynamic cultivation using a radial flow bioreactor (RFB) has gained increasing interest as a method of achieving bone regeneration. In order to enhance bone generation in large bone defects, it is necessary to use an RFB to expand the primary cells such as bone marrow cells derived from biotissue. The present study aimed to evaluate the cell expansion and osteogenic differentiation of rat bone marrow cells (rBMC) when added to basic fibroblast growth factor containing medium (bFGFM) or osteogenic differentiation factor containing medium (ODM) under dynamic cultivation using an RFB. Cell proliferation was evaluated with a DNA-based cell count method and histological analysis. An alkaline phosphatase (ALP) activity assay and immunohistochemistry staining of osteogenic markers including BMP-2 and osteopontin were used to assess osteogenic differentiation ability. After culture for one week, rBMC cell numbers increased significantly under dynamic cultivation compared with that under static cultivation in all culture media. For different culture media in dynamic cultivation, bFGFM had the highest increase in cell numbers. ALP activity was facilitated by dynamic cultivation with ODM. Furthermore, both BMP-2 and osteopontin were detected in the dynamic cultivation with ODM. These results suggested that bFGFM promotes cell proliferation and ODM promotes osteogenic differentiation of rBMC under dynamic cultivation using an RFB.

The purpose of this study was to investigate the influence of differences in axial thickness and type of cement on fracture load in CAD/CAM crowns. Assuming the mandibular first premolar to be the abutment tooth, 4 types of crown with different axial thicknesses and radii of curvature were prepared. To unify external design, the morphology of the crown margins was set at 0.15, 0.30, 0.45, or 0.60 mm, thus maintaining uniform axial form of the crowns. The CAD/CAM crowns and abutment teeth were bonded using each of 2 types of resin cement or polycarboxylate cement. The fracture load value was measured using a universal testing machine and the destruction phase observed.No significant difference was observed with change in axial thickness. The fracture load values with each of the 2 types of resin cement used were significantly higher than that with polycarboxylate cement (p<0.01). These results suggest that the fracture load values of CAD/CAM crowns are not influenced by differences in the axial thickness of the crown, and that they are higher when bonding is achieved with resin rather than polycarboxylate cement.

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