Blackwell Publishing Ltd
Dental pulp stem cells: what, where, how?
Dental pulp stem cells
ALASTAIR J. SLOAN & RACHEL J. WADDINGTON
Mineralised Tissue Research Group, Tissue Engineering and Regenerative Dentistry, School of Dentistry Cardiff University, UK
International Journal of Paediatric Dentistry 2009; 19: 61–70
Introduction. Itis now accepted that progenitor/ stem cells reside within the post-natal dental pulp. Studies have identiﬁed several niches of multipotent mesenchymal progenitor cells, known as dental pulp stem cells, which have a high proliferative potential for self-renewal. These progenitor stem cells are now recognized as being vital to the dentine regeneration process following injury. Understanding thenature of these progenitor/stem cell populations in the pulp is important in determining their potentialities and development of isolation or recruitment strategies for use in regeneration and
tissue engineering. Characterization of these cells, and determination of their potentialities in terms of speciﬁcity of regenerative response, may help direct new clinical treatment modalities. Such noveltreatments may involve controlled direct recruitment of the cells in situ and possible 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 may provide an innovative and novel biologically based new generation of clinical materials and/or treatments for dental disease. Aim. This study aimed toreview the body of knowledge relating to stem cells and to consider the possibility of these cell populations, and related technology, in future clinical applications.
The dentine–pulp complex has a natural regenerative potential leading to the formation of tertiary dentine. Odontoblasts may survive mild injury, such as attrition or early caries, and secrete a reactionarydentine matrix1,2. However, trauma of greater intensity, such as advanced caries or restorative procedures, may lead to the death of the pre-existing odontoblasts1,2. In response to stimuli at the dentine–pulp interface, new odontoblasts are recruited and differentiate at the site of injury to synthesize an atubular reparative dentine, also sometimes referred to as osteodentine. This reparative dentineprovides a ‘bridge’ of mineralized tissue immediately below the extensively damaged tissue, in order to preserve pulp vitality. A growing number of studies have now indicated that the post-natal pulp contains
Correspondence to: Dr. Alastair J. Sloan, Mineralised Tissue Research, Tissue Engineering and Regenerative Dentistry, School of Dentistry, Cardiff University, Heath Park, Cardiff, CF14 4XY,E-mail: firstname.lastname@example.org
© 2008 The Authors Journal compilation © 2008 BSPD, IAPD and Blackwell Publishing Ltd
several niches of potential progenitor/stem cells, which may have importance in mediating reparative dentine formation. Indeed, progenitor/ stem cell niches are continually being identiﬁed in all connective tissues of the body, where they play a fundamental role in wound repairprocesses. This subset of undifferentiated cells can represent as little as 1% of the total cell population. However, they produce multiple highly differentiated progeny in response to speciﬁc extracellular signals3. Central to the niche is the ‘true’ adult or ‘mother’ stem cell which displays an infrequent, yet almost unlimited self-renewal3. At mitosis, these cells give rise to a renewed motherstem cell and a daughter transit amplifying progenitor cell. These daughter progenitor cells possess a more limited capacity for self-renewal, but are highly proliferative. They also appear to control multi-potentiality, and are capable of following along several cell lineages to ultimately produce terminally differentiated cells such as osteoblasts, odontoblasts, adipocytes, chondrocytes, and...