The Study On The Regenerated Bone Regeneration Of Modified Advanced Platelet Rich Fibrin And Beta-tricalcium Phosphate In Different Proportions

Objective:The advanced platelet rich fibrin(A-PRF)is compounded with β-TCP in different proportions,the combination will be implanted in the bone defect of the femoral condyle of New Zealand rabbits,and observing the way of inducing osteogenesis,evaluating A-PRF and β-TCP under different composite proportion of newbone microscopic and bone biomechanical performance testing,screening can obtain a better effect of repairing bone defect of both composite proportion,provide reference for clinical induced bone regeneration.Methods: Building animal models,a critical bone defect with a diameter of 6.0mm and a depth of 8.0mm was prepared on the surface of the lateral femoral condyle of the New Zealand rabbit,and the area of titanium nail localization.A total of 32 New Zealand rabbits,only randomly selected 30 experimental rabbit.according to the different proportions of A-PRF and β-TCP were used to fill the defect area.divided into group A(A-PRF: β-TCP = 1:1)and group B(A-PRF: β-TCP = 2:1),group C(A-PRF:β-TCP = 4:1),group D(A-PRF: β-TCP = 1:2),group E(APRF: β-TCP =1:4),there were six rabbits in each group.Different proportions of composite materials were filled into the bone defect area respectively.The remaining 2were only for F group(blank control group),and only one critical bone defect was prepared,did not fill the material,and did not use the location nail.The animals were executed at 8W and 12 W respectively,general observation and X-ray examination,Micro-CT measurement analysis and bone compression test were performed.Results:The operation was successfully completed,and the New Zealand rabbit femoral condyle defect was successfully established.All the experimental results were statistically analyzed.General observation:overall,postoperative bone formation on the surface of 12 W is better than the surface of 8W.At 8W,the surface depressions of the bone defect were obvious,and the area of the newborn bone was darker than the surrounding bone,and it was dark red;The surface bone of group B was superior,and the bone surface of group E showed a small amount of β-TCP.At 12 W,there was a slight depression in the bone;A handful of new bone edge transition is not clear,especially in the group B.It was found that that bone defect boundary of the blank control group were obviously at 8W and 12 W after operation,and the fibrous granulation tissue was filled with bone defect area,there is no obvious new bone formation.X-ray examination:In each time node,there is no obvious high-density imaging of the β-TCP,which may be absorbed by the low content,scattered distribution and partial material metabolism.At 8W after surgery,group B had the smallest low-density bone defect,located in the middle of the bone defect area.In addition to the blank control group,the low density bone defect of group C was the largest and the boundary was not clear.The other three groups of low-density bone defects were indistinguishable from the naked eye.12 W compared with 8W after surgery,the range of low-density bone defect in the experimental group was gradually reduced from the edge to the center,and bone density from low to near normal bone.In group B,the interface was not distinguishable from that of the surrounding bone.The blank group presented a clear circular low-density defect area with no obvious new bone growth.Micro-CT measurement analysis:At 8W,each group showed clear arrangement of the bone trabeculae,the peripheral bone trabecular density was higher than the internal one,and the intramedullary cavity was larger.In group B,there were a large number of bone trabeculae,with a line or lamellar pattern,which was more closely aligned.In group C,the new bone trabeculae were striated,finer and less successional,and the number of bone trabeculae was small,and the gap between the small girders was large.To 12 W,bone trabecular arranged densely crisscross,the number increased obviously,the trabecular bone between the width of the medullary cavity significantly smaller,and only a small number of bone specimens are present in the central position of the bone specimen,which makes the new bone appear from the outward inward centripetal growth tendency.At 8W after surgery,(1)BV/TV,group B、group D and other groups have statistically significant difference(P<0.05),in which B>D,and group B were greater than group A,C,E;(2)Tb.N,There were statistically significant(P<0.05)in comparison group B,group C and group E with other groups,and B>E>C.(3)Tb.Th,there was no statistically significant difference between the five groups at the same time(P>0.05).(4)Tb.Sp,the differences between the group A,B and E were statistically significant(P<0.05),and C>E>A>B.At 12 W after operation,(1)BV/TV,B>A>E>C,there were statistical difference(P<0.05).(2)Tb.N,In addition to group A and group D,there were statistically significant differences between the other groups,and B>A>E>C,B>D>E;(3)Tb.Th,there was no statistical difference between the groups;(4)Tb.Sp,the difference between group B and group A,C,D and E was statistically significant(P<0.05).,and the Tb.Sp of group B was the smallest.In addition,there was no statistical significance between the two time nodes of the four indicators(P>0.05).Compression experiment:Compression strength test results,at 8W and12 W after operation,the compression strength of group C was smaller than that of the other groups,and the difference was statistically significant.In other four groups,at 8W,B>E>D>A.At 12 W,B>D>A>E,but there was no statistical significance between the groups(P>0.05).The compression strength of the five groups of 12 W was increased from 8w,and the difference between the two time nodes of each group was statistically significant(P<0.05).Elastic modulus test results,the elastic modulus of group C was smaller than that of the other groups at 8W,,and the difference was statistically significant.At 12 weeks,except for group A and B,there were significant differences between other groups.A and B are larger than the other three groups.And comparing12 w with 8w,the elastic modulus of five groups of 12 W was increased from8 w,and the difference in the two time nodes of each group was statistically significant(P<0.05).Conclusion:1.New Zealand rabbits were used as experimental subjects in this experiment to achieve better experimental results.A bone defect which was prepared with a diameter of 6.0mm and a depth of 8.0mm also meet the requirements of CSD.2.In X-ray and Micro-CT imaging tests,except for the blank group,the bone defect was basically unhealed,the imaging manifestations of bone defects in the other groups were all centripetal growth.3.According to the Micro-CT measurement analysis,the microstructure of the newborn bone induced by composites of group B(A-PRF:β-TCP =2:1)was the best.4.Through bone compression experiments,The biomechanical properties of group A and group B were better than those of the other three groups,but it was not possible to conclude that the biomechanical properties of group A and group B were the best.