The influence of perforating the autogenous block bone and the recipient bed in dogs. Part II: Histologic analysis

Objectives: This study histologically evaluated the influence of cortical perforation of grafted autogenous block bone (ABB) and/or the recipient bed at different healing periods in dogs. Material and methods: Four ABBs harvested from the posterior mandible were bilaterally fixed onto the maxillary premolar region in five mongrel dogs. The experiments involved four groups according to the perforation site: the ABB and/or the recipient bed. The animals were killed at 1, 4, and 10 days (early healing periods) and 4 and 8 weeks (late healing periods) postoperatively. Specimens were prepared for histological evaluation. Results: In the perforated ABB groups, blood clots had reached the inner surface of the ABB through a surgically prepared pathway, indicating that revascularization had taken place earlier than in the solid ABB groups. Finger-like bony projections into the graft were observed at the interfaces between the ABB and the recipient bed at the fourth week in all four groups. The remodeling process was observed over the entire ABB in the perforated ABB groups, whereas in the solid ABB groups it occurred only at the interface, and the ABB maintained its original lamella structure with more osteoclastic activity. Interestingly, in the perforated ABB groups, additional new bone with a smooth margin was formed above the block bone's original border. Conclusion: It was conjectured that intentional cortical perforation of the recipient bed and the ABB might enhance the initial angiogenesis and the integration of the graft.