【作者】 刘丽丽；

【导师】 马文盛； 董福生；

【作者基本信息】 河北医科大学 ， 口腔临床医学， 2010， 硕士

【摘要】 目的:通过建立Beagle犬牙槽隔减阻牙周膜牵张(periodontal ligament distraction,PDLD)快速移动牙齿的实验动物模型,观察压力侧牙周组织中RANKL和OPG的表达变化,并比较其与常规正畸牙齿移动过程中RANKL和OPG表达的区别,探讨RANKL和OPG在PDLD快速移动牙齿牙周组织改建过程中所起的作用,为研究PDLD快速移动牙齿过程中压力侧牙周组织改建的机制和临床运用提供理论依据。方法:8只纯种Beagle犬随机分为A组(加力1周)、B组(加力2周)、C组(加力2周,保持2周)和D组(加力2周,保持4周),每组二只,拔除8只Beagle犬下颌两侧第二前磨牙,采用自身对照设计,每只犬下颌的左右侧随机分为PDLD侧和常规方法正畸牙齿移动对照侧。以下颌第三前磨牙为支抗牙,下颌第一前磨牙为移动牙。上颌第一前磨牙为正常对照。PDLD侧移动牙远中牙槽间隔行减阻术,粘结牵张器,以2次/天的频率、每次将牵张器中螺旋扩大器的螺旋旋转90°,加力2周后固定保持。常规对照侧用NiTi螺旋弹簧牵引移动牙向远中,力约1.47牛顿,加力2周后固定保持。测量移动牙移动距离。实验动物在预先规定的时间取材,固定,脱钙,石蜡包埋,切片,HE染色观察移动牙压力侧牙周组织的形态学变化;TRAP染色观察压力侧牙周组织中破骨细胞数目的变化;免疫组化染色观察移动牙压力侧牙周组织中RANKL、OPG的变化,应用图像分析系统对RANKL、OPG含量进行半定量分析。并采用SPSS13.0统计软件对实验结果进行统计学分析。结果:1牙齿移动距离:加力1周时,常规对照侧牙齿向远中移动0.47±0.21mm,PDLD侧为1.47±0.55mm,两侧牙齿移动距离存在统计学差异(P<0.01)。加力2周时,常规对照侧远中移动0.68±0.59mm,PDLD侧为3.98±1.26mm,两侧牙齿总的移动距离存在统计学差异(P<0.01)。2 HE染色结果:加力后,常规对照侧移动牙压力侧牙周膜明显缩窄,可见明显无细胞结构的玻璃样变组织及潜掘性骨吸收,随着时间的延长玻璃样变组织逐渐被清除,牙槽间隔骨表面出现明显破骨细胞及骨吸收陷窝。PDLD侧牙周膜较常规对照侧受压缩窄程度轻,未见玻璃样变组织,随着加力时间的延长,远中固有牙槽骨弯曲或折断并进入拔牙窝,间隔骨周围及内部有大量破骨细胞,间隔骨吸收变薄,部分牙周膜与拔牙窝相通。加力2周,保持4周时,PDLD和常规方法移动牙压力侧牙周膜宽度基本恢复。3压力侧牙周组织中破骨细胞TRAP染色结果:PDLD侧和常规对照侧移动牙压力侧牙周组织中TRAP染色阳性破骨细胞在受力后均增加。PDLD侧在加力2周时,TRAP染色阳性破骨细胞个数达峰值。常规对照侧在加力2周,保持2周时达峰值。PDLD侧和常规对照侧的破骨细胞个数,在A组(P<0.01)、B组(P<0.01)和C组(P<0.01)中均存在统计学差异。4压力侧牙周组织中RANKL、OPG的表达变化:RANKL、OPG阳性着色部位主要位于牙周膜成纤维细胞、成骨细胞、血管内皮细胞、骨衬里细胞和骨陷窝内破骨细胞的胞浆。在常规对照侧,加力后RANKL和OPG的表达均逐渐增强,在加力2周,保持2周时RANKL的表达及RANKL/OPG含量比值达峰值,之后逐渐下降,而OPG的表达保持较高水平。在PDLD侧,加力后RANKL和OPG的表达均较强,在加力2周时RANKL的表达及RANKL/OPG含量比值达峰值,之后逐渐下降,而OPG的表达继续升高。在PDLD侧和常规对照侧的A组(P<0.01)、B组(P<0.01)和C组(P<0.05)中RANKL的表达均存在统计学差异。在PDLD侧和常规对照侧的A组(P<0.01)、B组(P<0.01)、C组(P<0.01)和D组(P<0.01)中OPG的表达均存在统计学差异。在PDLD侧和常规对照侧的A组(P<0.01)、B组(P<0.01)、C组(P<0.05)和D组(P<0.01)中RANKL/OPG含量比值均存在统计学差异。结论:1牙槽隔减阻牙周膜牵张移动牙齿可以明显加快正畸牙齿移动速度。2在观察时间内,牙槽隔减阻牙周膜牵张快速移动牙压力侧的破骨细胞数高于常规正畸牙齿移动,显示其压力侧发生较早与较快的骨吸收。3 RANKL和OPG参与牙槽隔减阻牙周膜牵张与常规正畸移动牙压力侧牙周组织的改建。RANKL/OPG含量比值的变化调节压力侧牙周组织中破骨细胞的产生及其吸收功能。与常规正畸牙齿移动相比,在牙槽隔减阻牙周膜牵张移动牙齿过程中RANKL、OPG的表达和RANKL/OPG含量比值变化更明显,从而导致其移动牙压力侧牙周组织的快速改建。更多还原

【Abstract】 Objectives:To establish the experimental animal model of rapid tooth movement through periodontal ligament distraction ( PDLD) with Beagles, to observe the difference of content change of RANKL and OPG in the periodontium on the pressure side between rapid tooth movement through PDLD and routine orthodontic tooth movement, which investigate the effect of RANKL and OPG on periodontium remodeling mechanism of rapid tooth movement through PDLD and provide theoretical base for clinical treatment.Methods:Eight beagles were divided into 4 groups randomly with 2 Beagles in each group: group A (1-week activating), group B (2-week activating), group C (2-week activating, 2-week retention) and group D (2-week activating, 4-week retention). The 2nd mandibular premolars were extracted on both sides of the eight Beagles, One side was chosen for PDLD and the other side for routine orthodontic tooth movement randomly. We defined the 1st mandibular premolars as the moved teeth and the 3rd mandibular premolars as anchorage teeth. The 2nd premolars of maxillary was the normal control. For PDLD side, the interseptal bone resistance was reduced, then a custom-made tooth-borne distractor was bonded. The distractor was activated 90°, twice a day for 2 weeks and followed by retention period. The NiTi spring was activated with a force of 1.47N for 2 weeks and followed by retention period on routine control side. The distance of tooth movement was measured. The dogs were sacrificed on each designed group time, dentoalveolar segment including the 1st and 3rd premolar were dissected out separately, fixed, decalcified, paraffin-embedded, sliced. The changes of periodontium on pressure side of moved tooth were observed with HE staining. The number of osteoclasts in periodontium on pressure side of moved teeth was counted with TRAP staining.The content change of RANKL and OPG in periodontium on pressure side were observed with immunohistochemical staining. The statistical analyses were performed using the SPSS13.0 statistical program.Results:1 distance of tooth movement:After 1 week activating, the distal movement of moved teeth on PDLD side was 1.47±0.55mm compared with 0.47±0.21mm on routine control side, there was significantly statistical difference of the distance of tooth movement between PDLD and routine control sides (P<0.01). After 2 weeks activating, the distal movement of moved teeth on PDLD side was 3.98±1.26mm compared with 0.68±0.59mm on routine control side, there was significantly statistical difference of the total distance of tooth movement between PDLD and routine control sides (P<0.01).2 results of HE staining:Along with the activation,the periodontium on pressure side was narrowed significantly, hyalinization and undermining resorption were discovered on the routine control side; during the retention period, hyalinization was removed gradually by osteoclasts. While the periodontium on pressure side was narrowed not significantly on the PDLD side, and the interseptal bone was compressed into the extraction socket rapidly and resorpted, with part of which joined with the extraction socket. There are a number of osteoclasts around and in the interseptal bone, and few hyalinization zone was discovered in the periodontium on pressure side of PDLD. After 6 weeks, the periodontium on pressure side of PDLD and routine control reverted to normal gradually.3 results of osteoclasts in the periodontium on pressure side with TRAP staining:Along with the activation, TRAP+ osteoclasts had increased in the periodontium on pressure side of PDLD and routine control. The TRAP+ osteoclasts increased significantly in the periodontium on pressure side and reached the peak on PDLD side in group B, and reached the peak on routine control side in group C. There were significantly statistical difference of the amounts of TRAP+ osteoclasts between PDLD and routine control sides in group A(P<0.01), group B(P<0.01) and group C(P<0.01).4 expression of RANKL,OPG protein in the periodontium on pressure side:RANKL and OPG protein expressed mainly in cytoplasm of osteoblasts, fibroblasts, bone lining cells, vascular endothelial cells and osteoclasts located in resorption lacunae. Along with the activation, expression of RANKL and OPG protein increased gradually in the periodontium on pressure side of the routine control. The expression of RANKL and RANKL /OPG ratio reached the peak on routine control side in group C, then decreased. The expression of RANKL protein and RANKL /OPG ratio reached the peak on PDLD side in group B. During retention period, the expression of RANKL protein and RANKL /OPG ratio reduced gradually on PDLD side, while the expression of OPG protein kept on a high level both on PDLD and routine control side. There were significantly statistical difference of the expression of RANKL protein between PDLD and routine control sides in group A (P<0.01),group B (P<0.01) and group C (P<0.05). There were significantly statistical difference of the expression of OPG protein between PDLD and routine control sides in group A (P<0.01), B (P<0.01), group C (P<0.01) and group D (P<0.01). There were significantly statistical difference of RANKL /OPG ratio between PDLD and routine control sides in group A (P<0.01), B (P<0.01), group C (P<0.05) and group D (P<0.01).Conclusion:1 The periodontal ligament distraction method could accelerate the tooth movement through reducing interseptal bone resistance.2 The amounts of TRAP+ osteoclasts in the periodontium on pressure side of PDLD were more than that of the routine control. Bone resorption on the PDLD side has occurred earlier and faster than that on the roution control side.3 RANKL and OPG participate the periodontium remodeling of tooth movement through PDLD and routine tooth movement. RANKL/OPG ratio regulates the differentiation and activation of osteoclast in the periodontium on pressure side during tooth movement. The content changes of RANKL and OPG and RANKL/OPG ratio in the periodontium on pressure side of PDLD are much obvious than those of routine orthodontic tooth movement, leading to the rapid remodeling of the periodontium on pressure side of PDLD tooth movement.更多还原