Activation of human dental pulp progenitor/stem cells in response to odontoblast injury

After incubation for 1 day, the BrdU was localised to the nuclei of cells in the perivascular area. The BrdU-immunolabelling exhibited a gradient. It was strong in the blood vessels surrounding the pulpal cavity and decreased in those away from the cavity. After incubation for 2 weeks, labelled cells were seen in the vicinity of the cavity. At 4 weeks, the immunolabelling was localised to the cavity area only. Control teeth without cavities or with shallow dentine cavities did not show any perivascular labelling after culture. These results clearly demonstrate that perivascular progenitor/stem cells can proliferate in response to odontoblast injury. They also show that these proliferating cells can migrate to the pulpal injury site in their tissue of origin simulating the situation in vivo.