Tehran University of Medical Sciences Frontiers in Dentistry 2676-296X 7 4 2010 12 15 185 195 MR. Baghaban Eslaminejad Associate Professor, Department of Stem Cell and Developmental Biology, Royan Institute for Stem Cel S. Vahabi Assistant Professor, Department of Periodontics, School of Dentistry, Shahid Beheshti University of M. Shariati Dentist, Department of Periodontics, Faculty of dentistry, Shahid Beheshti University, Tehran, Iran H. Nazarian Developmental Biology, Department of Stem Cell and Developmental Biology, Royan Institute for Stem C 2015 10 03 Objective: By date investigations have indicated the presence of stem cells within the pulp tissue of both temporary and permanent human teeth. In the present study, these stem cells were compared in terms of their growth kinetics and culture requirements. Materials and Methods: Stem cells within the pulp of the human third molar (permanent tooth) and the deciduous incisor (temporary tooth) were isolated, culture-expanded and characterized. Then the proliferation potential of the cells was compared using multiple cell growth indices as PDT (Population doubling time), colonogenic activity and growth curve. Furthermore, the cultures of both cells were optimized for maximal proliferation. Results: Stem cells of either pulp tissue appeared as fibroblastic cells capable of differentiating into osteoblastic, odontoblastic, adipocytic and chondrocytic cell lineages. In contrast to molar stem cells, those from the incisor tooth expressed neurogenic markers of ßIII Tubulin and Tau. Based on in vitro growth data, the cells from third molar tended to have a lower PDT value (20.79, SD=2.8 versus 25.55, SD=2.9 hours), higher colonogenic activity and better growth curve than those from the deciduous incisor (P<0.05). Both cells exhibited high expansion rate when being plated in a medium with 20% phosphate buffer solution at a density of 100 cells/cm2. Conclusion: Given the high proliferation capacity, the stem cells from the human third molar would be an appropriate candidate for use in experimental, preclinical and even clinical setups. https://fid.tums.ac.ir/index.php/fid/article/view/228 https://fid.tums.ac.ir/index.php/fid/article/download/228/228