牙槽嵴位点保存的动物实验研究

An experimental study of alveolar ridge preservation after tooth extraction in dog

目的:评估经位点保存方法处理过的拔牙窝与自然愈合位点相比其牙槽骨骨量在组织形态计量学上的变化。方法:拔除6只Beagle犬双侧下颌第二、第三及第四前磨牙(Pm2、Pm3、Pm4),随机分成3组:自然愈合组(T1),Bio-Oss Collagen组(T2),即刻种植联合Bio-Oss骨粉组(T3)。6个月后处死Beagle犬,切取样本,制作硬组织磨片,甲苯胺蓝染色后在光学显微镜下利用图像分析软件进行组织学观察及形态学测量。结果:所有实验位点颊侧牙槽嵴都发生明显的吸收。对于颊舌侧牙槽嵴顶吸收的相对高度值而言,T3与T1、T2组之间差异均有统计学意义(P<0.001),而T1与T2组间差异无统计学意义。对于颊舌侧骨壁的水平宽度值而言,在距舌侧牙槽嵴顶以下3、4 mm的位置,T1与T3组间差异均具有统计学意义(P=0.017,P=0.042),其他组间差异均无统计学意义。在距舌侧牙槽嵴顶以下5 mm的位置,3组间的差异均无统计学意义。结论:这两种牙槽嵴位点保存技术都不能完全保存拔牙窝原有的骨量。即刻种植联合Bio-Oss骨粉可以在一定程度上减少牙槽嵴吸收的量,而充填Bio-Oss骨胶原效果欠佳。

Objective To histomorphometricly assess changes occurred in the alveolar ridge following different methods of socket preservation and to compare them against natural healing without interventions. Methods The second, third and fourth mandibular premolars were extracted from six beagles. Six extraction sites in each dog were randomly assigned to three treatments as follows： natural healing （T1）, Bio-Oss Collagen （T2） and immediate implant with Bio-Oss （T3）. Six month after surgery, the dogs were euthanized and tissue samples were sectioned, fixed and mounted, then were stained with toluidine blue. The histologie studies and morphological measurements were performed by using an optical microscope and a digital image software. Results Reabsorption in the buccal aspect of the alveolar crest of ridge was showed in all groups. With respect to the mean vertical bone loss of the buccal bone plate, T3 is lower than T1 and T2（P 〈 0.001 ）, while no significant differences were observed between T1 and T2. With regard to horizontal dimension of the alveolar process, a statistical significance could be found at 3mm and 4mm below the crest of ridge in group T1 and T3 （P = 0.017, P = 0.042）, while no statistical differences were found between other groups. Conclusions Both techniques of alveolar ridge preservation were not able to completely preserve the original bone volume after tooth extraction. Immediate implant placement in combination with Bio-Oss seems to have the potential to limit the reabsorption of the alveolar process efficiently, but the bone preserving effect of Bio-Oss Collagen is undesirable.