TOOTH REGENERATION WITH DENTAL STEM CELL RESEARCH IN MINIATURE PIG MODEL

Abstract

To develop a cell-based approach to tooth regeneration, we isolated dental stem cells from tooth buds of mini pigs and culture-expanded them for about three weeks. Flow cytometry revealed that the majority of the proliferating cells were positive for stem cell surface markers, including CD105, CD29, CD44, CD71. These dental stem cells were then seeded in biodegradable agarose gel for autograft in various areas of the jaw bone. Mini pigs with tooth buds removed without transplantation of dental stem cells served as control. After one year, well differentiated tooth crown and root sheath were formed in mini pigs in the experimental group. The tooth formed by dental stem cells transplanted in alveolar bone was similar in size to original tooth crown (approximately 2 cm × 2 cm × 2 cm). The teeth formed by dental stem cells transplanted under the roots of the anterior teeth and in the cortical bone area were smaller. In the control group, the space where the tooth bud was extracted without cell transplantation was seen to be closed by forward movement of the posterior teeth. Histological analysis showed the structures of enamel, dentin and pulp in the regenerated tooth crown. Immunohistochemical analysis of amelogenin, type I collagen and bone sialoprotein confirmed enamel and dentin formation. Enamel and dentin structures on the regenerated tooth were also identified using scanning electron microscopy. These findings demonstrate a successful model of tooth regeneration from dental stem cells in mini pigs. In addition, local environment and available space also significantly affect the extent of tissue regeneration. Our study demonstrates the feasibility of using dental stem cells for tooth regeneration in clinical applications.