Bone Growth Regeneration Potential of Gingival Mesenchymal Stem Cells

Objectives: Ridge augmentation is an unpredictable and necessary surgical procedure for the successful placement of dental implants. This study proposes to augment a mandible ridge line via recruitment and differentiation of gingival mesenchymal stem cells (GMSCs). GMSCs provide an advantageous alternative because it has a low risk of rejection and disease transmission. Previous studies reported challenges in the delivery and the viability of transplanted GMSCs; therefore this study tested the osteogenic differentiation ability of the endogenous GMSCs in perforated membranes, which would allow GMSCs migration, as opposed to non-perforations membranes.
Methods: The premolars of five skeletally mature female dogs were removed and a large osteotomy of the ridge was performed. The surgical site was allowed to heal for 4 months prior to ridge augmentation surgical procedure. Surgical protocol used a lyophilized collagen sponges soaked in recombinant bone morphogenetic protein 2 (rh-BMP2). A titanium reinforced ePTFE membrane was then used and secured with stainless steel membrane tack in order to create adequate healing space and maintain ridge structure. New bone growth was assessed using microCT and the histological analysis.
Results: MicroCT results showed the ePTFE titanium reinforced membranes did not collapse, allowing for bone growth within the healing ridge site. MicroCT results also showed distinct difference in bone formation between the perforated and non-perforated membranes. The perforations allowed for migration and recruitment of bone remodeling cells throughout the healing site, above and below the membrane. The non-perforated membranes showed limited bone growth formation below the membrane with pockets of soft tissue. Histological analysis showed a significant amount of vasculature for the perforated membranes, while the non-perforated membranes showed granular tissue and minimal vasculature.
Conclusions: Results suggests the successful osteogenic differentiation of the GMSCs into osteoblasts throughout the healing site due to the perforation in the membrane. This allowed for the migration and recruitment of bone remodeling cells throughout the healing site versus the non-perforated membranes.