The management of facial defects has rapidly changed in the last decade. Functional and esthetic requirements have steadily increased along with the refinements of surgery. In the case of advanced atrophy or jaw defects, extensive horizontal and vertical bone augmentation is often unavoidable to enable patients to be fitted with implants. Loss of vertical alveolar bone height is the most common cause for a non primary stability of dental implants in adults. At present, there is no ideal therapeutic approach to cure loss of vertical alveolar bone height and achieve optimal pre-implantological bone regeneration before dental implant placement. Recently, it has been found that specific populations of stem cells and/or progenitor cells could be isolated from different dental resources, namely the dental follicle, the dental pulp and the periodontal ligament. Our research group has cultured palatal-derived stem cells (paldSCs) as dentospheres and further differentiated into various cells of the neuronal and osteogenic lineage, thereby demonstrating their stem cell state. In this publication will be shown whether paldSCs could be differentiated into the osteogenic lineage and, if so, whether these cells are able to regenerate alveolar bone tissue in vivo in an athymic rat model. Furthermore, using these data we have started a proof of principle clinical- and histological controlled study using stem cell-rich palatal tissues for improving the vertical alveolar bone augmentation in critical size defects. The initial results of the study demonstrate the feasibility of using stem cell-mediated tissue engineering to treat alveolar bone defects in humans.

Regeneration of periodontal tissues aims to utilize tissue engineering techniques to restore lost periodontal tissues including the cementum, periodontal ligament and alveolar bone. Regenerative dentistry and its special field regenerative periodontology represent relatively new and emerging branches of translational stem cell biology and regenerative medicine focusing on replacing and regenerating dental tissues to restore or re-establish their normal function lost during degenerative diseases or acute lesions. The regeneration itself can be achieved through transplantation of autologous or allogenic stem cells, or by improving the tissue self-repair mechanisms (e.g. by application of growth factors). In addition, a combination of stem cells or stem cell-containing tissue with bone implants can be used to improve tissue integration and the clinical outcome. As the oral cavity represents a complex system consisting of teeth, bone, soft tissues and sensory nerves, regenerative periodontology relies on the use of stem cells with relatively high developmental potential. Notably, the potential use of pluripotent stem cell types such as human embryonic stem cells or induced pluripotent stem cells is still aggravated by ethical and practical problems. Thus, other cellular sources such as those readily available in the postnatal craniofacial area and particularly in oral structures offer a much better and realistic alternative as cellular regenerative sources. In this review, we summarize current knowledge on the oral neural crest-derived stem cell populations (oNCSCs) and discuss their potential in regenerative periodontology.

The aim of this study was to analyze the success rate of dental implants and the graft shrinkage rate after vertical ridge augmentation and simultaneous implantation with an allograft bonering. Fifty-one patients (81 augmentations and simultaneous implantations) were included. The bonering technique followed a standardized protocol. The alveolar ridge was prepared using a congruent trephine, and depending on the defect size, an allograft bonering with an outer diameter of 6–7 mm was placed. The height of the bonering was trimmed with a diamond disc to the required length. The average height of vertical augmentation was 5.5 mm. Implants were inserted through the bonering into the native bone of alveolar ridge. After 6 months, dental implants were exposed, and dental prosthetics were placed. Of 81 implants placed with the bonering technique, two failed during a 12-month follow-up, corresponding to a success rate of 97.5%. One year after surgery, the allograft bonering exhibited an average vertical graft shrinkage rate of 8.6%. In conclusion, the allograft bonering technique was associated with a favorable outcome, and in cases with large vertical defects, both treatment time and donor site morbidity could be reduced.

The therapies to regenerate periimplant bone tissues have attracted lots of attention these years. Neural crest-related stem cells (NCSCs), a group of cells containing heterogeneous stem/progenitor cells, are capable of homing to injured tissues and participating in periimplant bone regeneration. The amplification of autologous NCSCs potential in homing for self-repair/regeneration, therefore, might be considered as an alternative therapy except for traditional cell transplantation. However, the knowledge of the NCSCs homing and participation in bone regeneration is still known little. Cell homing has been regarded as a process of exit of hematopoietic stem cells from blood vessels by trans endothelization and subsequent migration. Here we broadly define cell homing as active recruitment of endogenous cells, including stem/progenitor cells, into an anatomic compartment. Accordingly, research is becoming increasingly focused on the homing and stimulation of native cells.For the purpose of directly observing NCSCs involvement in periimplant bone repair, different animal models were established to make their oral-derived NCSCs reconstituted with cells regenerating periimplant bone tissues. Here, we present a histological study for delivering homing factors to the site of implant placement by incorporation to allogen bone substitute as stem cell carrier material. We further show therapeutic strategies focusing on the stimulation of endogenous cells to support periimplant bone repair. NCSCs were found to aggregate in the periimplant niches and emerge in newly-formed bones or fibers. Some of them also co-expressed markers of fibroblasts or osteoblasts. These results indicated that NCSCs might contribute to the formation of new fibers and periimplant bone tissue during periimplant bone regeneration. In conclusion, we speculated that autologous NCSCs can shift into the surgical sites created by implant placement and participating in periimplant bone tissue repair.

No abstract