Journal of Dental Medicine

Background and Aims: In the last decade, several studies have reported the isolation of stem cell population from different dental sources, while their mesenchymal nature is still controversial. The aim of this study was to isolate stem cells from mature human dental pulp and follicle and to determine their mesenchymal nature before differentiation based on the ISCT (International Society for Cellular Therapy) criteria.
Materials and Methods: In this experimental study, intact human third molars extracted due to prophylactic or orthodontic reasons were collected from patients aged 18-25. After tooth extraction, dental pulp and follicle were stored at 4°C in RPMI 1640 medium containing antibiotics. Dental pulp and follicle were prepared in a sterile condition and digested using an enzyme solution containing 4mg/ml collagenase I and dispase (ratio: 1:1). The cells were then cultivated in α-MEM medium. Passage-3 cells were analyzed by flow cytometry for the expression of CD34, CD45, CD 73, CD90 and CD105 surface markers.
Results: Dental pulp and follicle were observed to grow in colony forming units, mainly composed of a fibroblast-like cell population. Flow cytometry results showed that dental pulp and follicle are highly positive for CD73, CD90 and CD105 (mesenchymal stem cell markers) and are negative for hematopoietic markers such as CD34 and CD 45.
Conclusion: In this study we were able to successfully confirm that dental pulp and follicle stem cells isolated from permanent third molars have a mesenchymal nature before differentiation. Therefore, these two sources can be considered as an easy accessible source of mesenchymal stem cells for stem cell research and tissue engineering.

Dentistry has been a field dominated by a constant improvement of synthetic biomaterials. Tissue engineering of tooth is coming to change the panel of the dental materials such as restorative materials and implants. Certainly, it is the largest transition in history of dental materials science in terms of accepting this new and exciting technology. The objective of this article is to present various implications of tissue engineering in different fields of dentistry. To achieve this goal, a review of the literature was carried out by using Medline database to search topics including "dental stem cells", "teeth tissue engineering", "regenerative dentistry", "oral surgery", "periodontal regeneration" and "regenerative endodontics". These searches were limited to articles published after the year 2000. On the basis of our literature review, we have found that although there are significant challenges in oral tissues engineering, engineered tissues will find many applications in dentistry within the next few years.

Background and Aims: The exfoliated human deciduous tooth contains multipotent stem cells [Stem Cell from Human Exfoliated Deciduous tooth (SHED)] that identified to be a population of highly proliferative and clonogenic. These cells are capable of differentiating into a variety of cell types including osteoblast/osteocyte, adiopcyte, chondrocyte and neural cell. The aim of this study was to evaluate the differentiation of SHED to osteoblast in standard osteogenic medium and comparing the results with medium which supplemented with glucosamine in form of chitosan.

Materials and Methods: Dental pulp cells were isolated from freshly extracted primary teeth, digested with 4 mg/ml collogenase/dispase, and grown in Dulbecco's modified Eagle's medium with 10 percent fetal bovine serum. The clonogenic potential of cells was performed after 3 weeks of culture. Flowcytometric analysis, performed at day 21 of culture to identify surface markers of mesenchymal stem cells. The cells from 3rd passage were used for osteogenic differentiation in routine osteoinductive medium. Chitosan (10 μg/ml) was added to the culture medium of case group. Alizarin Red Staining and Alkaline Phosphatase (ALP) activity were done to evaluate osteogenic differentiation in the developing adherent layer on the third passage. The results were analyzed using T-test. For the analysis of normal distribution of data, non-parametric Kolmogrov-Smirnov test was used.

Results: The colonogenic efficiency was more than 80%. Flowcytometric analysis showed that the expression of mesenchymal stem cell marker CD90, CD105 and CD146 were positive in SHED, while hematopoietic cell marker CD34, CD45 and endothelial cell marker CD31 were negative. Quantitative analysis of Alizarin Red Staining demonstrated that: mineralized nodule formation was higher in the group supplemented with glucosamine (chitosan). Results from Alkaline Phosphatase activity test, on day 21, demonstrated a significantly higher ALP activity in the group supplemented chitosan (P<0.001).

Conclusion: Stem cells isolated and cultured from exfoliated deciduous teeth pulp can be differentiated to osteoblast. Addition of chitosan can be beneficial to promote osteogenic differentiation of these cells.

  Background and Aims: In the last decade, several studies have reported the isolation of stem cell population from different dental sources, while their mesenchymal nature is still controversial. The aim of this study was to introduce the isolating methods for stem cells from human dental pulp and to determine their mesenchymal nature before differentiation.

  Material and methods: One of the best sources for stem cell is dental pulp tissue. Dental Pulp Stem Cells (DPSCs) would be the most convenient source of stem cells because teeth were easy to retrieve and removed throughout life. Pulp is a specialized connective tissue including blood and lymph vessels, nerves, and the interstitial fluid. DPSCs can be found within the ‘‘cell rich zone’’ of pulp. DPSCs have been isolated for the first time in 2000 by Gronthos these cells exhibited a differentiation potential for odontoblastic, adipogenic and neural cytotypes. Gronthos isolated stem cells in 2 different methods: The enzymatic digestion method and the second was out growth, these cells could be cryopreserved in liquid nitrogen. It has also been shown that human DPSCs can be used for complex structures such as pulp or woven bone formation in vivo.

  Conclusion: DPSCs originate from the cranial neural crest and have neural characteristics such as the expression of neurotrophins. Therefore, DPSCs may represent a promising source in cell therapy for neurological disorders. Characterization of these cells and determination of their potentialities in terms of specificity of regenerative response will form the foundation for development of new clinical treatment modalities, whether involving directed recruitment of the cells and seeding of stem cells at sites of injury for regeneration or use of the stem cells with appropriate scaffolds for tissue engineering solutions. Such approaches will provide an innovative and novel biologically based on new generation of clinical treatments for dental disease.