الفهرس 
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Abstract
Both dental pulp stem cells (DPSC) from permanent teeth
and stem cells from human exfoliated deciduous teeth (SHED)
have attracted tremendous interest recently by playing a major
role in tissue engineering and regenerative medicine.
This research focuses on studying stem cells isolated from
he pulp of permanent teeth (DPSC) and exfoliated deciduous
eeth (SHED) populations with regard to their proliferation and
capability to differentiate into osteogenic lineage. Materials and Methods To determine the existence of such a cells in the dental pulp;
we applied methodology that had been previously developed
for the isolation and characterization of BMSCs and dental pulp stem cells ( Gronthos et al., 2000, Miura et al., 2003 ). Collected teeth were allocated into two main groups: I) DPSC Group:This group included human dental pulp tissues obtained
from impacted third molars from patients aged 16–26 years
II) SHED group: This group included human dental pulp tissues obtained
from clinically healthy, but luxated deciduous incisors from
children aged 6-8years. Cell Isolation and Culture: Extirpated pulp tissue was digested in a solution of 3 mg/mlcollagenase type I and 4 mg/ml dispase for 30–60 min at 37°Cand then stem cells were collected.Following, the isolated cellswere the cells were resuspended at density of 10.000 cells/cm2in complete culture media. The culture media consisted ofalpha modified Eagle‟s medium (aMEM) with L-glutamine,(Gibco, Invitrogen Life Technologies,USA)supplemented with 10 % fetal bovine serum, (Gibco,Invitrogen Life Technologies,USA), antibiotics;penicillin/streptomycin (Penicillin G100 unit/ml andSterptomycin 100 µg/ml) and finally antimycotic agent(Fungizone, 0.25 µg/ml) in sterile 25 cm2 polysterine filter capcell culture plates and incubated at 37°C in a humidifiedatmosphere of 5% CO2.The medium was changed once everyfour days. Passaging was performed when primary cell culture of adherent cells reached 70% confluence and was named passagezero (P0) later passages were named accordingly. The primary
cell culture was thus propagated and expanded in repeated cell
cultures. Cells were sub cultured every other week and culture
medium was replaced every 3 days. Assesing Proliferation Capability:
To assess the proliferation capacity of the isolated stem cells
from both tissues; colony formation efficiency testing and
MTT assay were done. The colony formation efficiency of both
tissues was observed from the first day of culture to give cells
from permanent and deciduous pulp tissues adequate time to
demonstrate their difference in growth patterns since some
tissues form colonies earlier than the other. Evaluation of Osteogenic Differentiation of Cultured Cells:
In order to determine the differentiation ability of DPSC and
SHED from passage three , Cells from the third passage were
cultured in osteogenic medium consisting of 50 mg/ml Lascorbic
acid, 10m M dexamethasone and 10 mM ßglycerophosphate.
The cellswere maintained in differentiation cultures for 3 weeks. Also, the effect of BMP2 with the culture medium was also investigated as a potent osteogenic
differentiation inducer. Osteogenic differentiation wasevaluated by Alizarin Red Stain and RT-PCR. To confirm osteogenesis, the cells were also examined by RT-PCR for the
expression of several osteoblast-related genes including Bone
Sialoprotien II and Osteocalcin (OC).