Fig. 1. Isolating dental pulp and establishing three-dimensional (3D) explant culture. (A) Schematic representation of 3D explant culture is shown. The intact pulp tissue was retrieved after cracking tooth with hammer and placed between 25% and 50% Matrigel. Dental pulp was eventually submerged in 25% Matrigel with addition of medium on the top (XF medium: xeno-free StemMACS MSC Expansion Media Kit XF). (B) The intact pulp was taken from supernumerary tooth and subjected to 3D culture. Cone-beam computed tomography scan and stepwise procedures are shown (EC: explant culture). (C) Representative phase contrast image (left, scale bar=1,000 μm) and H&E staining image 10× (right) of 3D explant culture of human dental pulp tissue are shown. Preexisting pulp is shown dark in the phase contrast and the outgrowth area is identified at the periphery. (D) Occasional accumulation of partial dentin on the surface of 3D explant culture is detected after 4 weeks.