Background and Objective: It has been hypothesized that mesenchymal stem cells (MSCs) is probably precursor cells of PDLCs and may play a key role in the modeling and remodeling of periodontal tissues. This research is to observe the location and number of MSCs in human periodontal ligament during orthodontic treatment and discuss effects of mechanical-biological reaction of MSCs in the human periodontal ligament under orthodontic tooth movement.
Material and Methods: The fresh extracted and intact teeth, which have been extracted before and in the orthodontic treatment were collected, fixed in 4% paraformaldehyde, decalcified in 20% ethylenediamine tetraacetic acid and embedded in paraffin in preparation for HE and immunohistochemistry. Antibodies against CD44, CD146 and STRO-1 were used to identify the putative stem cells and observe the location and number of MSCs in human periodontal ligament during orthodontic treatment.
Results: MSCs were identified in the periodontal ligament of both two groups. They were mainly located in the paravascular region and small clusters of cells were also found in the extravascular region, especially in the apical and the coronal one third part of root. Wider distribution and more cells were detected in the sections of periodontal ligament of orthodontic treatment group.
Conclusion: The increased quantity and wider distribution of MSCs in the orthodontic tooth movement indicates that MSCs may play an important role in the modeling and remodeling of periodontal tissues. the mechanical-biological reactions of MSCs is an important ingredient of the repairment and re-establishment of periodontal tissues under orthodontic tooth movement.