Alveolar bone regeneration by transplantation of periodontal ligament stem cells and bone marrow stem cells in a canine peri-implant defect model: a pilot study.
Kim SH, Kim KH, Seo BM, Koo KT. J Periodontol. 2009;80:1815-1823.
BACKGROUND: The present study was undertaken to evaluate the potential of periodontal ligament stem cells (PDLSCs) and bone marrow SCs (BMSCs) on alveolar bone regeneration in a canine peri-implant defect model.
METHODS: Four adult, male beagle dogs were used in this study. Autologous BMSCs from the iliac crests and PDLSCs from extracted teeth were cultured. Three months after extraction, BMSC- and PDLSC-loaded hydroxyapatite/beta-tricalcium phosphate (HA/TCP) (test groups) and cell-free HA/TCP (control group) were implanted in three rectangular, saddle-like peri-implant defects, respectively. The left side of the mandible was initially prepared, and after 8 weeks, the right side was also prepared. The animals were sacrificed after an 8-week healing period. Undecalcified ground sections were prepared. New bone formation and bone-to-implant contact (BIC) were measured histomorphometrically. BMSCs and PDLSCs were fluorescently labeled and traced.
RESULTS: Alveolar bone regeneration in surgically created peri-implant saddle-like defects was more effective in test groups than the control group. The BMSC group had the highest new bone formation (34.99% and 40.17% at healing times of 8 and 16 weeks, respectively) followed by the PDLSC group (31.90% and 36.51%) and control group (23.13% and 28.36%), respectively. Test groups exhibited a significantly higher new bone formation than the control group at 8 weeks, but the same was true for only the BMSC group at 16 weeks (P < 0.05). Fluorescently labeled cells were identified adjacent to HA/TCP carriers and, partly, near connective tissues and osteoids.
CONCLUSION: This study demonstrated the feasibility of using stem cell-mediated bone regeneration to treat peri-implant defects.
Stem cells have the potential to change the way we treat a number of dental conditions. One of the richest and easily acquired sources for stem cells is exfoliated deciduous teeth. Instead of discarding extracted deciduous teeth as medical waste, patients and parents of young patients can save these teeth for their stem cells. Stem cells afford our patients the potential ability to participate in life-saving treatments derived from dental stem cells. Dental stem cells have the same potential as bone-marrow derived and adipose-tissue derived stem cells in curing a number of diseases. In medicine today, stem cell-based treatments are being used and investigated for treatment of such diverse conditions as Parkinson’s disease, diabetes, liver disease, neural degeneration following brain injury, cardiovascular disease, and autoimmune diseases. From a dental standpoint, stem cell research in dentistry is investigating the potential for periodontal regeneration, regeneration of the dental pulp and dentin, the creation of physiologic scaffolds for the replacement of orofacial bone and cartilage, and the potential to regenerate damaged or defective salivary glands.1
These two studies present very cutting-edge information concerning ongoing dental research investigating stem cell research for regenerative therapies in dentistry. The extension of this research is: Can we reconstruct and repair bony defects using pulpal stem cells? The repair and regeneration of bone is a significant issue in the oral-maxillofacial field and for the human body in general. Bone loss can be caused by many different diseases (congenital and degenerative), traumas, and surgical procedures. If repairs can be done using these techniques, quality of life issues due to bone loss and bony defects can be addressed in a positive way. Also, in the pilot study by Kim and co-researchers there were significant differences in alveolar bone regeneration from both the BMSC group (highest new bone formation) and the PDLSC group when compared to the control. Their findings provide a vision of the potential for using stem cell-mediated bond regeneration to treat peri-implant defects.
1. Mao JJ, Collins F. Stem cells: sources, therapies and the dental profession. Dental Office Magazine. February 2008:38-46.
Commentary by Howard E. Strassler, DMD
Howard E. Strassler, DMD
Professor and Director of Operative Dentistry
Department of Endodontics, Prosthodontics and Operative Dentistry
University of Maryland Dental School