[摘要] 目的：探讨大鼠磨牙牙周膜废用性萎缩功能状态对正畸牙槽骨改建的影响。方法：选择30只5周龄体重(250 g±20 g)的SD大鼠,随机分为牙周膜废用性萎缩组(15只)和正常对照组(15只)。通过拔除实验组大鼠右下颌所有磨牙使右上颌第一磨牙丧失咬合接触，3周后形成牙周膜废用性萎缩动物模型。在两组大鼠上颌切牙和第一磨牙间放置5 mm镍钛螺簧,初始力值50 g，近中移动磨牙。分别于加力后0、3、7、14 d处死动物，通过组织学方法对第一磨牙压力侧牙槽骨破骨细胞进行染色并记数；并对14 d组拍摄X光片测定牙齿移动距离。结果：牙周膜废用性萎缩组牙齿移动距离(0.611 mm±0.142 mm) 小于正常对照组(0.679 mm±.090 mm)，差异无显著性(P>0.05)；萎缩组大鼠压力侧破骨细胞数在实验全过程中(除0 d外)均低于对照组，差异有显著性。结论：正畸治疗中，无咬合接触的牙周膜废用性萎缩牙较正常咬合接触牙对矫治力反应差，骨改建率低，易发生玻璃样变和潜掘性骨吸收，延缓牙移动，因此对无咬合接触牙的临床治疗中应采用轻力。

    [关键词] 骨改建 牙周膜 废用性萎缩 正畸牙移动

    Bone Remodeling Related to Hypofunctional Periodontal State in Experimental Tooth Movement.

    QI Juan, MAO Jing, Yang Ping.

    Department of Stomatology, TongJi Hospital of HuaZhong Science and Technology University, Wuhan 430030

    [Abstract]Objective: The aim of this study was to investigate, in a rat model, whether a state of hypofunctional periodontium had an effect on the rate of bone remodeling induced by orthodontic treatment. Methods: 30 five-week-old rats (250g±20g) were divided into normal group(n=15) and hypofunctional group(n=15). A rat model of hypofunctional periodontal state was established by extracting the right mandibular molars, so that the right maxillary first molar was induced into occlusal hypofunction as the biting force lessened. After 3 weeks, mesial orthodontic force was applied among the two groups by means of a 50-gram-force closed -coil spring ligated to the right upper first molar and incisors for 0, 3, 7, 14 days respectively, after which the animals were sacrificed. The osteoclasts from histological sections, identified by tartrate-resistant acid phosphatase(TRAP), were observed and counted with microscope. Orthodontic tooth movement (OTM) was determined by measuring the space created between the maxillary first and second molars on tracings of the roentgenograms of the 14d groups. Results: 1)There was no significant difference (P>0.05) in OTM between normal group(0.679mm±.090mm) and hypofunctional group(0.611mm±0.142mm); 2)The number of osteoclasts on the pressure side in the hypofunctional group was significantly smaller than that in the normal group through the experimental period(except for 0 day). Conclusions: Non-occluding teeth with a hypofunctional periodontium have a lower rate of bone remodeling, and are more susceptible to the injury in periodontal tissues caused by orthodontic force than normally occluding teeth, such as hyalinization or undermining bone resorption, even dentin resorption. This reminds clinicians to treat such patients with lighter forces. ......