牵张成骨后正畸牙龈沟液中AST水平变化研究

发布时间：2018-11-26 12:05

【摘要】：目的通过犬下颌骨牵张成骨动物模型的建立,观察在不同时机将实验牙移入牵张成骨再生区后龈沟液(GCF)中天冬氨酸转氨酶(AST)的动态变化,从而分析其牙周组织的改建情况。方法选取8只无牙周疾病且正常恒牙列beagle犬,排除患有牙周疾病,第三前磨牙缺损、冠折、松动、畸形等牙体牙髓疾病犬只。在其下颌骨第三、四前磨牙之间进行牵张成骨术后形成一定距离的新骨区,随机将8只犬分为两组,即一组为2周后将牙齿移入骨再生区,另一组为6周后移动牙齿,每组均为4只。通过采用离心洗涤法回收吸滤纸上的龈沟液以检测其AST水平,观察该两组实验牙在不同时点(1d/2d/3d/7d/14d/28d)、不同位点(近中和远中)的龈沟液中AST水平动态改变。结果所有被选的实验动物均能耐受牵张成骨手术,牵张成骨再生区间隙内均被新生骨组织替代,基本获得预期牵张距离。牵张成骨新骨区触其质地较坚硬,骨的连续性也较好,骨皮质基本平整,未出现牵张成骨术区下颌骨大面积的骨缺损或者骨不连等不良症状,但舌侧较为膨隆且表面轻度粗糙感。牵张成骨后对形成的新骨区骨密度利用X线片进行对比观察后发现与自体骨的骨密度基本一致,两种骨质间未见明显界限。当两组实验牙在受力三天后AST水平是呈现逐渐上升趋势,其上升幅度第2周较第6周移动实验牙更为明显;在7d时反而开始出现下降趋势,21d时AST水平达到最低后恢复上升趋势;当28d时AST水平再次达到较高水平。结论:本实验选用beagle犬作为牵张成骨动物实验对象,根据自身特点自制牵张装置,建立了相对科学、简单、可靠的动物模型。实验中其牵引速度与频率均能在可控范围内,为以后在其他相关牵张成骨实验中奠定了动物模型的基础。研究还发现牵张成骨2周后实验牙移入骨再生区龈沟液AST整体水平较6周后明显升高,但随着时间的推移AST水平改变并非呈线性升高,这种改变对今后临床研究有一定的指导意义。虽然通过移动的距离能够体现成骨2周后移动牙齿较6周移动速度较快,但本研究通过分析移动牙龈沟液中AST水平的变化进一步发现其移动牙周组织的破坏相对也较为严重。因此通过分析龈沟液中AST的动态改变能够作为判断和选择牵张成骨后施加正畸力最佳时机的有效指标。但由于采用beagle犬作为实验对象,其成本相对较高,造成本实验仅为小样本的动物实验,所得结论仍需进一步研究与论证。
[Abstract]:Objective to observe the dynamic changes of aspartate aminotransferase (AST) in gingival crevicular fluid (GCF) after the mandibular distraction osteogenesis model was established in dogs. Thus, the reconstruction of periodontal tissue was analyzed. Methods eight beagle dogs with no periodontal disease and normal permanent dentition were selected and were excluded from periodontal disease, third premolar defect, crown fracture, loosening, malformation and other dental pulp diseases. After distraction osteogenesis between the third and fourth premolars of the mandible, 8 dogs were randomly divided into two groups: one group (2 weeks later) and the other group (6 weeks) moving teeth. There were 4 rats in each group. Gingival crevicular fluid (GCF) from filter paper was recovered by centrifugal washing method to detect the level of AST. The experimental teeth of the two groups were observed at different time points (1d/2d/3d/7d/14d/28d). The dynamic changes of AST level in gingival crevicular fluid at different sites (near and far). Results all the selected experimental animals were able to tolerate distraction osteogenesis and were replaced by new bone tissue in the space of distraction osteogenesis regeneration zone. The expected distraction distance was obtained. The new bone area of distraction osteogenesis is hard, the continuity of bone is better, the bone cortex is flat basically, and there are no adverse symptoms such as large area of bone defect or nonunion of mandible in distraction osteogenesis area. But the tongue side was bulging and slightly rough. After distraction osteogenesis, the bone mineral density of the new bone region was observed by X-ray film. The results showed that the bone density of the new bone was basically the same as that of the autogenous bone, and there was no obvious boundary between the two kinds of bone. The AST level of the two experimental teeth increased gradually after three days of stress, and the increase was more obvious in the second week than in the sixth week. On the contrary, the AST level began to decrease at 7 d, reached the lowest level at 21 d, then recovered to increase trend, and AST level reached a higher level again at 28 d. Conclusion: in this experiment, beagle dog was selected as experimental object of distraction osteogenesis, and a relatively scientific, simple and reliable animal model was established according to its own characteristics. The traction speed and frequency can be controlled in the experiment, which lays the foundation of animal model in other related distraction osteogenesis experiments. It was also found that the overall level of AST in gingival crevicular fluid was significantly higher than that after 6 weeks of distraction osteogenesis, but the change of AST level was not linear with the passage of time. This kind of change has certain guiding significance to the clinical research in the future. Although the movement of teeth after 2 weeks of osteogenesis was faster than that of 6 weeks, the change of AST level in moving gingival crevicular fluid was found to be relatively serious by analyzing the changes of AST level in moving gingival crevicular fluid. Therefore, the dynamic change of AST in gingival crevicular fluid can be used as an effective index to judge and select the best time to apply orthodontic force after distraction osteogenesis. However, the cost of using beagle dog as experimental object is relatively high, so this experiment is only a small sample animal experiment, and the conclusions need to be further studied and demonstrated.
【学位授予单位】：安徽医科大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：R783.5

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