Runx2 is a new transcription factor that takes part in odontoblast differentiation. This study is aimed at investigating the immunolocalization and expression of Runx2 in the process of dental pulp injury and repair using immunohistochemical technique. In normal dental pulp, positive staining can hardly be detected. In experimental groups, strong positive staining was detected at the site of the impaired pulp after 1 day, while only weak Runx2 staining was detected 3 days after operation. Five days later, a large number of stellate cells in the root apex expressed Runx2, and after 7 days, followed by the reparative dentinogenesis, Runx2 expression vanished slowly, then totally disappeared. Taken together, the expression of Runx2 has temporal and spatial specificity during different phases in rat tertiary dentinogenesis.
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