【作者】 冯立晓；

【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， 2008， 硕士

【摘要】 目的:通过建立Beagle犬牙周膜牵张成骨(Distraction of the Periodontal Ligament,DPDL)快速移动牙齿的实验动物模型,观察牙周组织中I、III型胶原含量的变化。探讨牙槽隔减阻牙周膜牵张成骨对Beagle犬牙移动速率以及对牙周膜内胶原纤维代谢的影响。从而为今后的系列研究和临床应用奠定基础。方法:将9只纯种雄性Beagle犬随机分为1W、2W、4W、6W四组(每组二只)和正常对照组(一只)。9只犬拔除两侧下颌第二前磨牙,并随机选择其中8只犬的一侧为DPDL侧,另一侧为常规方法对照侧。以下颌第三前磨牙为支抗牙,下颌第一前磨牙为移动牙。自制牵张器;拔牙凿骨减阻;粘结牵张器;DPDL侧以2次/天的频率、0.175毫米/次的速率加力2W后固定保持。常规方法对照侧移动牙施加150g力值,加力2W后,固定保持。测量移动牙移动距离;定期拍摄X线片观察成骨情况。实验动物在相应时间取材,固定,脱钙,石蜡包埋,切片,HE染色观察移动牙张力侧牙周膜变化;苦味酸天狼猩红染色,偏振光显微镜下观察移动牙张力侧I、III型胶原含量变化,对实验结果应用SPSS11.5统计软件进行统计学分析。结果:加力1W时,DPDL侧移动牙平均向远中移动1.14mm,常规方法对照侧移动牙平均向远中移动0.37mm( p <0. 001);加力2W时,DPDL侧移动牙平均向远中移动3.76mm,常规方法对照侧移动牙平均向远中移动0.57mm ( p <0. 001)。X线显示,加力2W时,DPDL侧移动牙张力侧牙周膜内有新骨形成,常规方法对照侧骨形成不明显。保持4W时,DPDL侧骨改建基木完成,由快速牵张生成的新生骨放射学特征与正常对照侧无明显差异。组织学变化:HE染色的结果,加力1W时,DPDL侧移动牙张力侧牙周膜较常规方法对照侧显著增宽,牙周膜内成纤维细胞和成骨细胞增多。加力2W时,DPDL侧移动牙张力侧新生板层状牙槽骨明显增多;常规方法对照侧新生骨量少呈均质状。DPDL侧4W组牙周膜宽度基本恢复正常;6W组两种方法作用下移动牙张力侧牙周膜己无明显差异。苦味酸天狼猩红染色结果观察,DPDL侧移动牙张力侧牙周膜中I型胶原含量在2W时达峰值75.23%,常规方法对照侧I型胶原含量也于加力2W时达峰值76.27%,且高于DPDL侧(P<0.01),两种方法作用下I型胶原含量的增加较正常对照侧均有显著性差异(P<0.01)。DPDL侧移动牙张力侧牙周膜III型胶原含量于加力1W时达峰值20.16%,常规方法对照侧III型胶原含量加力2W时达峰值20.14%,无论是DPDL侧还是常规方法对照侧,其I、III型胶原的变化均有时间依赖性。结论:1.成功建立了Beagle犬牙周膜牵张成骨快速牙齿移动的实验动物模型。2.通过牙槽隔减阻的DPDL方法可大大加快正畸牙齿移动速度。3.减阻牵张移动牙齿与传统移动牙齿方法的胶原代谢规律相似,但时间提前即代谢加快。提示牙周膜牵张成骨快速牙齿移动与传统牙齿移动的生物学机制相同,但是牙周膜的代谢速度加快。对牙周膜牵张快速移动牙齿方法的长期效果还需做进一步研究。更多还原

【Abstract】 Objectives:To set up the experimental animal model of distraction of the periodontal ligament (DPDL) after reducing interseptal bone resistance, compared the speeds of tooth movement between methods of DPDL and roution orthodontic tooth movement, and to observe the difference of content changes of collagen I and III between the two methods.Methods:Nine male purebred Beagle dogs were randomly divided into 5 groups as 6W group, 4W group, 2W group, 1 W group (each group has two dogs) and the normal control group(one dog). The second mandibular premolars were extracted on both sides of the nine dogs. We selected one side for DPDL and the other side for roution orthodontic tooth movement.We defined the first mandibular premolars as the movement teeth and the third mandibular premolars as anchorage teeth. The second premolars were extracted and the interseptal bones were undermined then a tooth-borne, custom-made distractor was bonded on DPDL side;While a NiTi spring was bonded on the other side after the second premolar extracted. The distractor was activated 0.35mm/d, twice a day for 2 weeks and followed by retention period. The NiTi spring was activated about 150g force for 2 weeks and followed by retention period. The distance of tooth movement was measured, and periodic X-rays were taken for observation of bone formation.Sacrificed the dogs followed by the above individual group time frame and fixed,decalcified,paraffin-embedded ,sliced. The periodontal ligament tension side changes of the moved tooth were harvested for HE staining and observed under light microscope. The content changes of collagen tape I and III on tension side were observed under a polarizing light microscope with Picrosirius Red Staining (PRS). The statistical analyses were performed using the SPSS11.5 statistical program.Results:After one week, the first mandibular premolars were distalized an average of 1.14mm on the DPDL side compared with 0.37mm on the roution control side. Significant difference was observed between the two methods(P<0.001). By the time of two weeks, the first mandibular premolars were distalized an average of 3.76mm on the DPDL side compared with 0.37mm on the roution control side. Significant difference was observed between the two methods(P<0.001). New alveolar bone was generated and remodeled rapidly in the tension side of PDL during and after the distraction from X-ray views.No obvious bone formation was observed on the roution control side.In the histological study, After one week, periodontal ligament was significantly wider in DPDL side than in roution control side.The proliferation of fibroblasts and osteoblasts in the tension side of experimental side was more than the roution control side.The roution control side showed new bone less homogeneous. The periodontal ligament width in 4W group returned to normal.The periodontal ligament of the 6W group under the two methods had been no significant difference.Through the method of Picrosirius Red Staining, the increment of Collagen Type I in the tension side of DPDL group was less than the routine control group both on the end of one week and two weeks. The peak value of Collagen Type I in the DPDL side appeared at the end of two weeks(75.23%) compared with that in the roution control side(76.27%) at the end of two weeks.Significant difference was observed between the two methods(P<0.01). Under both methods the content increment of Collagen Type I was significantly different compared with the normal control side (P<0.01).The peak value of Collagen Type III in the DPDL side appeared at the end of one week(20.16%) compared with that in the roution control side(20.14%) at the end of two weeks.Significant difference was observed between the two methods(P<0.01).The changes of Collagen Type I and III in both DPDL side and roution control side were time dependent.Conclusions: 1.The animal model of DPDL after reducing interseptal bone resistance of beagle dog was feasible.2. The DPDL method could accelerate the tooth movement through reducing interseptal bone resistance.3. The metabolism of collagen of rapid tooth movement through distraction of the periodontal ligament was similar to the roution orthodontic tooth movement, but it was more quickly. So this method could accelerate the renovation of Periodontal Ligament.Moreover, the long-term effects of this method were unknown and further research was needed.更多还原