RESUMO
<p><b>OBJECTIVE</b>To find an ideal method inducing dental pulp stem cells (DPSC) osteogenic differentiation. To compare the effect of co-culture method and that of mineralizing culture medium.</p><p><b>METHODS</b>DPSC were co-cultured with osteoblasts using cell culture inserts system as experiment group, and DPSC were cultured in mineralizing culture medium as control group. The cell morphology and ultrastructure and mineralized nodes were analyzed under phase contrast microscope, transmission electron microscope, and alizarin red S staning. Bone sialoprotein (BSP), Runx-2, osteocalcin, and collagen-1 (Col-1) osteoblastic genes expressions of DPSC cultivated in special niche of osteoblasts were assayed by reverse transcription polymerase chain reaction (RT-PCR).</p><p><b>RESULTS</b>The mineralization nudoles of experiment group were more than control group. Fifteen days later, BSP and Col-1 genes in the DPSC of co-cultures were 9.807 ± 1.135 and 2.913 ± 0.310, respectively. And those in the DPSC of mineralizing culture medium were 6.478 ± 0.781 and 1.703 ± 0.184, respectively. Co-cultures and mineralizing were significantly different (P < 0.05).</p><p><b>CONCLUSIONS</b>As osteoblasts can secret lots of osteogenic cell cytokines, they have more significant effect than mineralizing culture medium on osteogenesis of DPSC.</p>