Title: Bio-action of Alveolar Bone Remodeling by Piezoelectric Surgery in Rats
Taisuke Ohira (Presenter)
Alessia De Vit, Boston University
Wayne gonnerman, Boston University
Serge Dibart, Boston University
Objectives: Piezoelectric bone surgery (PIEZO) is a minimally invasive procedure for cutting bone more precisely and less traumatically than the conventional osteotomies, using 3D ultrasonic vibration. Our previous studies demonstrated that PIEZO and orthodontic tooth movement can work at almost twice the speed compared to conventional methods by rapidly inducing bone resorption and subsequent regeneration. We believe that PIEZO could have a positive contribution to periodontal tissue regeneration. However, more studies are required regarding regulatory molecules and cellular activities by PIEZO. In this study, we focused on PIEZO regulated cellular activity (e.g. osteocytes, osteoclasts, osteoblasts).
Methods: 90 rats were divided into 3 groups (each n=30): two different frequency of Piezo bone injury (10Hz & 30Hz), and control (no intervention). The maxillae and blood sample were collected at 6 time-points (each n=5, post-operative at day 1, 3, 7, 14, 28, 70) for biological image analysis (MRI and histology) and biochemical analysis, respectively.
Results: PIEZO resulted in significant tissue and biochemical changes. Histological analysis and MRI data indicated the demineralization process starts at day 1 and peaks at day 7. The remineralization process begins at day 14 and continues until complete healing by day 70. TUNEL assay showed the early demineralization following piezoelectric injury was initiated by Osteocyte Apoptosis. Osteoclast activity (TRAP) was induced at day 3 and reduced at day 14. In the post-operative early phase, serum c-terminal telopeptide collagen type I crosslinks, a bone degradation biomarker, significantly increased in the 30Hz Piezoelectric surgery at day 7 (p<0.05). In addition, Picrosirius Red histological analysis showed deteriorated collagen structure in the early phase and starting structural recovery at day 14.
In the post-operative day 7-14, serum ALP activity was significantly increased (p<0.05), and high number of RUNX2 positive osteoblast progenitor cells were observed in the PDL around acellular new bone.
Conclusions: These results indicate that PIEZO in periodontal tissue causes alveolar bone decalcification and subsequent regeneration. Further elucidation of the effect of PIEZO on periodontal tissue may provide a new target for the regenerative treatment of periodontal diseases.