The Elementary Study Of Tooth Regeneration From Stem Cells From Human Exfoliated Deciduous Teeth

This study attempted to establish the method of rapid expansion of stem cells from human exfoliated deciduous teeth(SHED) and did the elementary exploration about regeneration of tooth from SHED. The studies included isolating, culturing and identifying of SHED; establishing the method of rapid expansion of SHED; Alu and Pfl digoxigenin-probe preparative; recombinating between the first branchial arch epitheliums of mouse embryos (E10.5) and SHED; recombinating between the second branchial arch epitheliums of mouse embryos (E10.5) and SHED; recombinating between tooth epitheliums of mouse embryos (E13.5) and tooth mesenchyme cells of mouse embryos (E13.5) mixed into 50% SHE D; checking mouse tissue and human tissue with DNA in situ hybridization.By isolating and culturing SHED , the result demonstrated that the cells grew most rapidly when they were initially plated at low densities (1.5 cells/cm2). In three passages in which the cells were plated at low density, they were amplified about 10~10-10~11-fold in 6 weeks. The cells retained their ability to form calcified deposition and the average percent cfus at the end of the third passage(six weeks) was about the same as the initial value for the samples (55% vs. 58%) and therefore apparently retained their multipotentiality for differentiation. This study used mouse as an animal model to establish a set of technique and we are improving it. By using it, mouse tooth can be regenerated in ectopic body. Human and mouse chimera tissue-recombination experiment not only demonstrated that the reciprocal interactions between tissues of different species may induce tooth development but also demonstrated elementarily that SHED only haveodontogenic competence and they have not odontogenic potential. SHED can be induced by epitheliums or mesenchyme cells that both have odontogenic potential to differentiate into tooth tissue.