Periodontal healing using a collagen matrix with periodontal ligament progenitor cells in a dehiscence defect model in beagle dogs

Purpose: To histologically characterize periodontal healing at 8 weeks in surgically created dehiscence defects in beagle dogs that received a collagen matrix with periodontal ligament (PDL) progenitor cells. Methods: The bilateral maxillary premolars and first molars in 6 animals were used. Standardized experimental dehiscence defects were made on the buccal side of 3 premolars, and primary culturing of PDL progenitor cells was performed on the molars. Collagen matrix was used as a scaffold and a delivery system for PDL progenitor cells. The experimental sites were grafted with collagen matrix (COL), PDL progenitor cells with collagen matrix (COL/ CELL), or left without any material (CTL). Histologic and histomorphometric analyses were performed after 8 weeks. Result: The defect height from the cementoenamel junction to the most apical point of cementum removal did not significantly differ across the CTL, COL, and COL/CELL groups, at 4.57 +/- 0.28, 4.56 +/- 0.41, and 4.64 +/- 0.27 mm (mean +/- standard deviation), respectively; the corresponding values for epithelial adhesion were 1.41 +/- 0.51, 0.85 +/- 0.29, and 0.30 +/- 0.41 mm (P<0.05), the heights of new bone regeneration were 1.32 +/- 0.44, 1.65 +/- 0.52, and 1.93 +/- 0.61 mm (P<0.05), and the cementum regeneration values were 1.15 +/- 0.42, 1.81 +/- 0.46, and 2.57 +/- 0.56 mm (P<0.05). There was significantly more new bone formation in the COL/CELL group than in the CTL group, and new cementum length was also significantly higher in the COL/CELL group. However, there were no significant differences in the width of new cementum among the groups. Conclusion: PDL progenitor cells carried by a synthetic collagen matrix may enhance periodontal regeneration, including cementum and new bone formation.