Introduction of a Mixture of β-Tricalcium Phosphate Into a Complex of Bone Marrow Mesenchymal Stem Cells and Type I Collagen Can Augment the Volume of Alveolar Bone Without Impairing Cementum Regeneration

Background: The purpose of this study is to evaluate whether beta-tricalcium phosphate (beta-TCP) could be a promising modality to help augment alveolar bone in periodontal tissue regeneration by bone marrow mesenchymal stem cells (BMMSCs). Methods: Expanded BMMSCs and atelocollagen (Col) were mixed together (MSC/Col). A combination of beta-TCP with MSC/Col was also prepared (MSC/Col/TCP). MSC/Col/TCP or MSC/Col was transplanted into experimental periodontal Class III furcation defects that had been exposed to inflammation in beagle dogs. Periodontal tissue regeneration was evaluated by histologic and morphometric analyses at 4 and 8 weeks after transplantation. Results: MSC/Col and MSC/Col/TCP enhanced periodontal tissue regeneration compared to Col and TCP/Col according to hematoxylin and eosin staining. The percentage of new cementum length in the MSC/Col/TCP group was not significantly different from that in the MSC/Col group at 4 and 8 weeks. On the other hand, the percentage of new bone area in the MSC/Col/TCP group was much higher than that in the MSC/TCP group at 4 weeks. However, at 8 weeks, no significant difference in new bone area was found between the two groups. In the MSC/Col/TCP group, beta-TCP was surrounded by newly formed bone. Multinucleated cells, which were positive for osteopontin and tartrate-resistant acid phosphatase, were present in the interconnected macropores of beta-TCP. Conclusion: These findings suggest that beta-TCP is applicable as a scaffold for BMMSCs transplantation and helps augment alveolar bone without impairing regeneration of cementum.