Study On The Changes Of AST Levels In Gingival Crevicular Fluid After Distraction Osteogenesis

Objective Through the establishment of canine mandibular distraction osteogenesis animal model, the dynamic changes of AST in gingival crevicular fluid(GCF) were observed after the teeth were moved into the new bone area at different time,andanalyze the remodeling of periodontal tissue.Method The distraction osteogenesis surgical procedure was performed in 8 beagle dogs without periodontal disease and normal teeth,exclude the dogs suffering from periodontal disease, third molars without defects, anterior crown fracture, loosening, deformities and other dental diseases.Distraction osteogenesis was performed between mandibular third and four mandibular molars to form a certain distance of bone regeneration zone. The 8 dogs were divided into two groups randomly, each group had 4 dogs, and the teeth were moved into the new bone area after 2 weeks and 6 weeks.Through the method of centrifugation and washing recovery after absorbing filter paper in gingival crevicular fluid detecting AST levels and observe the dynamic changes in two groups of teeth in different time point(1d/2d/3d/7d/14d/28d) and differnt site(mesial and distal) in gingival crevicular fluid.Results All animals grew well and their mandibles were all lengthened. The newly formed bone was demonstrated. Touch the new bone area of hard texture,good continuty of bone, bone cortex is basically flat, no large area of the mandible bone defect or nonunion and other adverse symptoms,but the tongue side is more swelling and the surface of mild rough.The new bone density was observed by X-ray.The new bone and bone mineral were basically the same,and there was no significant difference between the two kikinds of bone.The AST level of gingival crevicular fluid in experimental tooth is rising for the first three days, and the group of two weeks were significantly higher than 6 weeks.The AST level declined after 7d, in 21 d up to the minimum, and gradually restored.In the 28 d AST levels reached a higher level again.Conclusion The beagle dogs can be used be establish the tooth movement model after distraction osteogenesis, which is a relatively scientific, simple, reliable animal model. Experimental traction speed and frequency can be in the controllable range.So in other related distraction bone in the experiment lay the foundation for the animal model. The AST level of experimental teeth increased significantly after 2 weeks than after 6 weeks. But over time the AST level change is not linear, this change has certain guiding significance to the clinical research in the future. In the distraction osteogenesis after re inspection time, repair to periodontal properly adjust. The dynamic change of GCF in AST, can be used as a clinical decision stretch into the effective index of bone boosting the expected effect, should be popularized.but due to the relatively high cost of the experimental object in beagle dogs, resulting in the experiment only for small sample of animal experiments, on income still need to further research and demonstration.