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目的建立实验性正畸牙移动保持期的动物模型,以利于研究保持期骨改建规律。方法于2008年4月在吉林大学口腔医院动物实验室,选用36只8周龄雄性Wister大鼠,以上颌前牙为支抗牵引第一磨牙向近中移动,加力21d后去除加力装置。以每只大鼠的左侧牙弓为实验侧,右侧牙弓为对照侧。在实验侧安装保持装置,分别保持1、3、7、14、21、28d;对照侧不做任何处理。在加力结束后和保持结束后即刻制取上颌石膏模型,测量所有模型的第一磨牙面近中沟与第二磨牙面远中沟的距离,计算加力结束后与保持结束后的距离,比较实验侧与对照侧的牙齿移动距离,评价保持装置的有效性。结果实验侧在保持结束后第一磨牙复发距离明显小于对照侧,二者差异有统计学意义(P<0.05)。结论以Wister大鼠为实验对象,采用正畸结扎丝结扎法建立的正畸牙移动保持期动物模型是有效的。

Establishment of the animal model of experimental orthodontic tooth movement in the period of retention.

Abstract：Objective To establish an animal model of experimental tooth movement for research on the regulation of bone remodeling during retention. Methods Experimental tooth movement was performed in 36 male Wistar rats at 8 weeks of age in the animal laboratory in Dental Hospital of Jilin University in April，2008. Bilateral maxillary first molars were forced to move mesially with closed coil spring for 21 days. After remove of the closed coil spring，the left maxilla was considered as experimental side and the right maxilla as control side. The retentive appliances were placed on the molars in the experimental side and the molars in control side were untreated. Retentive appliances were maintained respectively for 1，3，7，14，21 and 28d. At the end of experimental tooth movement and retention，maxillary dental casts were made. The interdental distance between the mesial groove of the first molars and distal groove of the second molars was measured on the maxillary dental casts. The interdental distances at the end of experimental tooth movement and retention were calculated. The effectuality of retentive appliances was evaluated by comparing the tooth movement distances between the experimental side and control side. Results The relapse distance of the first molars in the experimental side was significantly smaller than that in the control side at the end of the retention（P < 0.05）. Conclusion Wistar rat model of retention after orthodontic tooth movement with ligature wire is applicable.