| Objective:To compare the effects of calcined natural bovine bone(CBB)and nano-hydr oxyapatite/ collagen(HAC)repair materials on the bone defect of rat skull perfor ation.This study provided the basis for the selection of bone meal in guided bone regeneration(GBR).Methods:Eighteen male SD rats were selected to create a skull critical size defect model,and round full-layer bone defects with a diameter of 5mm were made on both sides of the midline of the skull,respectively,and divided into experimental group(implanted with calcined natural bovine bone repair materials)and control group(implanted with nano-hydroxyapatite/ collagen repair materials).At 4 weeks,8 weeks and 12 weeks after operation,6 skull specimens were sacrificed respectively,and the skull specimens in the operative area were collected for Micro CT scanning and HE staining.To compare the osteogenic effect of bone defect area between the two groups: Bone volume/Tissue volume,(BV/TV),Trabecular thickness(Tb.Th),Trabecular number(Tb.N),Trabecular space(Tb.Sp)and bone volume fraction(BVF).The obtained data were processed and analyzed by SPSS 22.0 statistical software,and P < 0.05 indicated statistically significant differences.Results:The results of Micro CT scan showed that bone formation increased at 4,8 and 12 weeks after operation.By comparing the volume fraction of new bone,the thickness of bone trabeculae and the number of bone trabeculae in the two groups at the same time point,all the data in the nano-hydroxyapatite/ collagen(n HAC)group were higher than those in the calcined natural bovine bone(CBB)group,and the bone trabecular space was lower than that in the calcined natural bovine bone(CBB)group,P<0.05,and the difference was statistically significant.HE staining results of histological sections showed that there was no obvious absorption of calcined natural bovine bone(CBB)bone particles 4 weeks after operation,and the volume fraction of new bone was 9.52±1.29%.A small amount of irregular absorption began to occur around the nano-hydroxyapatite/ collagen(n HAC)bone meal,and the volume fraction of new bone was 14.31±1.44%.At 8 weeks after operation,there was a small amount of insect erosion at the edge of calcined natural bovine bone(CBB),and the volume fraction of new bone was 17.20±1.86%.The nano-hydroxyapatite/collagen(n HAC)bone particle area decreased,the volume fraction of new bone was23.56±1.98%,which contained a small number of new capillaries and fibrous connective tissue.At 12 weeks after operation,the residual bone meal of calcined natural bovine bone(CBB)was perfectly fused with new bone tissue,and the volume fraction of new bone was 33.76±2.00%,containing a very small amount of new capillaries and fibrous connective tissue.The remaining bone meal of the nano-hydroxyapatite/ collagen(n HAC)was almost completely absorbed,and the volume fraction of new bone was 41.06±2.24%.There were a large number of new capillaries and a small amount of fibrous connective tissue.P<0.05,the difference was statistically significant.Conclusion:1.The osteogenesis speed of calcined natural bovine bone(CBB)repair material is slow,and the absorption rate of bone graft material is slow.The new bone contains very little blood vessels and connective tissue,and the bone is hard and similar to“the cortical bone”.2.The osteogenesis speed of nano-hydroxyapatite/ collagen(n HAC)repair material is fast,and the absorption rate of bone graft material is fast.The new bone contains rich blood vessels and a small amount of fibrous connective tissue,and the bone is soft,similar to“the spongy bone”. |
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