The Role of Physical Effects in Material Induced Bone Formation聽
Sabah Oghazian, Second Year, MSc of Dental Sciences-Thesis, UU直播.聽聽
Co-Authors: Nicholas Makhoul, Jake Barralet聽
Background: Reconstruction of cranial defects presents challenges due to the intricate local environment and unique skull features. Although autografts are the gold standard, resorption and limited availability confine the utility. Synthetic materials show promise but fall short in promoting rapid repair. Cell-based tissue engineering must overcome regulatory and safety concerns. This study aims to establish a controlled environment, using physical stimuli for targeted bone formation. These bony and hematopoietic tissues could replace current methods for cranial defect repair, overcoming existing limitations.聽
Methods: We conducted this pre-clinical study using male Wistar rat models. Glass and silicone open-ended tubes were introduced subcutaneously and subperiosteally over the skull. All tubes had identical dimensions (6 mm height, 7 mm inner diameter, and 9 mm outer diameter). Following the euthanasia 8 weeks after implantation, gross examination, micro-CT analysis, and histological evaluation were done.聽
Results: Macroscopic examination of silicone tubes showed a thin central cord of tissue while cords in the glass group were shorter and thicker. Dermal tissue drawn into glass tubes was greater compared to the silicone tubes, although basal tissue volume did not show a significant difference (p-value > 0.5). Micro-CT images indicated no bony structures in silicone tubes, while osseous features were shown in all glass specimens. Bone volume averaged 1.63 mm鲁 in subcutaneous implants and 11.8 mm鲁 in subperiosteal implants. In subcutaneous glass tubes, bone structures did not contact the calvarium, whereas in the subperiosteal group, they adhered near the walls, resembling cranial bone in structure. Histological examination revealed vascularization in all cords. In the silicone group, basal tissues comprised connective tissue and inflammatory cells, with no evidence of bone formation. Microscopic examination of basal tissue in glass tubes confirmed the presence of the osseous tissue.聽
Conclusion: Physical stimuli inducing bone formation can be applied via hard and inert glass tubes. Soft silicone tubes displayed cord formation but lacked bony structures, while glass tubes showed osseous features. These findings emphasize the potential of physical stimuli for cranial defect repair. Further research is crucial for optimizing this approach for application in critical-sized defects, either through direct defect coverage or as a viable source for autograft harvest.聽