| Objective: Heterogeneous freeze-dried bone and its compound with PRFwere used for bone defect repair in this experimental study. Furthermore, thecritical-sized bone defects model of rabbits was used to evaluate the efficiencyof the construct. It was observed and analyzed their effect on osteogenesis inbone defect and osseointegration around titanium screw nail.Methods:1Grouping:12healthy New Zealand white rabbits were randomlydivided into3groups (n=4) with self-control method. The right side ofmandible was experimental group，which would be applied with PRF andheterogeneous freeze-dried bone compound, and the left side was the controlgroup with heterogeneous freeze-dried bone. All of the animals were killedafter4,8,12weeks respectively.2Preparation of heterogeneous freeze-dried bone: Heterogeneous bonewas taken from human bone tissue and prepared by means of cleaning bonemarrow, deep freezing, freeze-dried and ray irradiation.3Preparation of the PRF:5mL of whole blood was drawn from themedial ear artery of the rabbit without anticoagulant, the blood was thensubjected to centrifugation at3000rpm for10minutes. Platelet-rich fibrin(PRF) would be harvested by Choukroun’s method as follows: three layers areformed in the centrifuge tube after centrifugation, platelet poor plasma on thetop; red blood cells at the bottom, and the middle layer is platelet-rich fibrin.Discarding the supernatant, the fibrin gel (7.5×4.0×0.4mm) containing PRFcould be obtained from5ml arterial blood.4Modeling and intervention: Normal New Zealand white rabbits weresubjected to removal (5×4×3mm) of alveolar bone of incisor distal of mandible. The trailing edge of the defect was about4centimeters from themental foramen and the inferior margin was at the same level as the mentalforamen. Then we made tow holes on edges of the defect respectively. Thetitanium screw nails were implanted in holes. The right side was theexperimental group. It was filled with PRF and heterogeneous freeze-driedbone. The left was the control group, which was filled with heterogeneousfreeze-dried bone alone. Then sew up the incision. After surgery, the diet canbe recovered to normal.5Observations: All the experimental animals were killed after4,8,12weeks respectively by air embolism. The healing situation of mandiblesamples were observed by gross observation, torque test, hematoxylin-eosin(HE) staining and the slice image of bone defect was acquired by computerimage analysis system acquisition, and account for the percentage of new bornarea in visual field.Results:1Gross observation: the titanium screw nails were stable, and theexterior of the defect were covered by bone in both groups, but with differentfullness.2The strength of osseointegration were measured separately by torquetest. The result had significant difference between the experimental group andthe control group (P<0.05). The results of torque test showed that the strengthof osteointegration in experimental group were significantly higher than thatin controls (P<0.05).3Histological analysis showed new bone formed around the titaniumscrew nails in experimental group was significantly much more than that incontrol group (P<0.05).Conclusion:1The two materials showed a certain remediation effect. Heterogeneousfreeze-dried bone and its PRF compound had active effect on bone defectosteogenesis and osseointegration around titanium screw nail.2Compared with the controls, the defect filled with PRF and heterogeneous freeze-dried bone compound healed better, more new bone wasregenerated, suggest the compound could speed up the bone regeneration. |
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