Application of periodontal ligament cell sheet for periodontal regeneration: a pilot study in beagle dogs

Objective: The ultimate goal of periodontal treatment is to regenerate the damaged periodontal support. Although periodontal ligament (PDL) cells are essential for periodontal regeneration, few studies have reported the transplantation of periodontal ligament cells to periodontal defects. We developed a new method to apply periodontal lig ament cells as a sheet to the defect. The aim of this study was to investigate the periodontal healing after application of the periodontal ligament cell sheet in beagle dogs. Methods: Autologous periodontal ligament cells were obtained from extracted premolars of each beagle dog. Periodontal ligament cell sheets were fabricated using a temper ature-responsive cell culture dish. Dehiscence defects were surgically created on the buccal surface of the mesial roots of bilateral mandibular first molars of each. dog. In the experimental group (five defects), periodontal ligament cell sheet with reinforced hyaluronic acid carrier was applied to the defect. Only the hyaluronic acid carrier was applied to the contralateral side as a control (five defects). Fight weeks after surgery, the animals were sacrificed and decalcified specimens were prepared. Healing of the periodontal defects was evaluated histologically and histometrically. Results: No clinical signs of inflammation or recession of gingiva were observed in both experimental and control groups. In the experimental group, periodontal tissue healing with bone, periodontal ligament and cementum formation was observed in three out of five defects. In the control group, such periodontal tissue formation was not observed except in one defect. Histometric analysis revealed that the formation of new cementum in the experimental group was significantly higher than that in the control group. Conclusion: The periodontal ligament cell sheet has a potential to regenerate periodontal tissue and may become a novel regenerative therapy.