There is growing interest in stem cells due to their ability to develop into different types of cells and their use to treat serious illnesses, offering possibly limitless medical applications. Though they can be harvested from other areas of the body with difficulty, stem cells can also be obtained from the dental pulp in a non-invasive method of collection. The donor teeth should be healthy and can be deciduous, wisdom or adult teeth removed for orthodontic or other diagnostic reasons.
Stem cells are inherently present in the body and are involved in regular repair and replacement of worn out or damaged tissues. A stem cell is an undifferentiated cell characterised by its ability to generate specialised cells by differentiation and to multiply infinitely and identically (self-renewal), especially in culture. Human stem cells are classified into three types according to their origin:
Embryonic. These are totipotent stem cells present in the embryo shortly after fertilisation. The term totipotent means that these cells are the source of all the tissues in our bodies. Under specific controlled conditions, their differentiation can be directed toward a given cell type (nerve cells, muscular cells, blood cells and many more). The removal of such stem cells requires the destruction of the embryo. Research on embryonic stem cells currently has been curtailed, mainly for ethical reasons.
Fetal. These cells are pluripotent which means they have already been assigned to a specific tissue cell type and unlike totipotent cannot be the source of all the various tissues types, unlike embryonic stem cells. They can be harvested from aborted fetuses.
Adult. These cells are pluripotent or multipotent which means they can differentiate into several cell types of the same family (for example hematopoietic stem cells can differentiate into red blood cells, white blood cells, platelets). These stem cells are the basis for tissue renewal and repair following injury and are already being used in the treatment of more than 100 diseases.
Pulp stem cells
Stem cells harvested from the dental pulp of extracted teeth are adult pluripotent stem cells and can be isolated and grown in the laboratory in their undifferentiated state. Stem cells from dental pulp will offer tremendous therapeutic potential in the context of maxillofacial application, bone regeneration, spinal cord injuries, cardiovascular diseases, neurodegenerative diseases and treatment of the eye. A single wisdom tooth will provide 300,000 cells per pulp. Donor teeth should be kept intact if possible and selected according to the following criteria:
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Mobility – this should be less than grade I–II for deciduous teeth.
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Age – younger teeth are better because the quantity and quality of stem cells decreases after 40 years of age.
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Completeness – the presence of the roots and the pulp.
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Healthy – an absence of periodontal or apical infection.
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Strong – intact and caries free.
Processing procedure
After extraction the tooth is opened in a laboratory clean room under strict sterile conditions. The extracted dental pulp is dissociated using a special device that allows the selection of very small cells which also contains stem cells. The cell suspension enriched with stem cells can then be cryogenically stored by cooling to a temperature below -130°C. Using this technique it is possible to preserve the stem cells for several decades in a tissue bank for when they may be required by the donor for future therapeutic reasons.
Applications
Cell therapy is already a recognised part of regenerative medicine that uses stem cells, or cells derived from stem cells, to regenerate or repair damaged cells or tissues. These cells are currently being used in a variety of ways:
- Injected into the blood.
- Transplanted directly into the site (bone graft, neuronal and spinal repair, corneal reconstruction).
- Recruited from the patient’s own tissue by bone marrow transplant.
Although treatments with stem cells from other sources have been used with success, dental pulp stem cells are still being used in clinical studies (in vitro and animal model stage) and clinical trials (maxilla facial bone reconstruction). However, there are over 5,000 ongoing clinical trials of new treatments involving stem cells (including those from dental pulp), that could soon be available to patients. By banking their stem cells now patients are investing in their future. There are now over 600 scientific papers about stem cell use (540 relating to treatment in humans) on the ‘Entrez PubMed’ clinical research database. This shows just how quickly interest in this area has grown and gives an insight into how important it will be in the future. By offering this service to your patients you will be offering them the opportunity to have their or their children’s stem cells harvested and preserved ready for future medical application.