Soft Tissue Augmentation Using Silk Gels: An In Vitro and In Vivo Study

Background: Restoration of a three-dimensional shape with soft tissue augmentation is a challenge for surgical reconstruction and esthetic improvement of intraoral mucosa and perioral skin tissues. A connective tissue graft or free gingival graft, classically used for such indications, requires a donor site, which may lead to various clinical complications. Methods: In this article, a new three-dimensional scaffold made of silk fibroin that could be of great interest for these indications was studied. Mechanical tests were conducted to characterize the physical properties of the materials. The biocompatibility of such scaffolds was positively assessed in vitro using a combination of immunostaining, 5-bromo-2'-deoxyuridine proliferation assays, and histologic staining. Finally, the shaped material was grafted subcutaneously in nude mice for a long-time implantation study. Results: Human fibroblasts embedded in this material had a survival rate up to 68.4% and were able to proliferate and synthesize proteins. One month after subcutaneous implantation, the three-dimensional soft tissue augmentation was stable, and histologic analysis revealed revascularization of the area through the biomaterial. A mild inflammatory reaction disappeared after 12 weeks. Conclusion: The results indicate that silk-gel material was able to create a lasting three-dimensional soft tissue augmentation and is a promising biomaterial for periodontal and maxillofacial therapies, either as a scaffold for cells or alone as a biomaterial. J Periodontol 2009;80:1852-1858.