后牙双斜面导板矫治器对生长期大鼠下颌形态的影响

Effect of twin inclined plane appliance on the mandible morphology in growing rats

目的:探讨后牙双斜面导板矫治器(TIPA)对生长期大鼠下颌骨不同部位形态的影响。方法:应用自行设计的TIPA引导6周龄大鼠下颌后退。测量实验组和对照组大鼠在3,14,30和60 d时髁突和下颌骨不同部位的形态。结果:TIPA实验组在30 d:下颌的长度(A-F)、髁突的长度(B-F)和髁骨长度(C-D)明显变短,有统计学差异(P<0. 05),并持续到第60天。髁突长轴与下颌平面的交角(BF/GH)明显变大,有统计学差异(P<0. 01)。TIPA实验组在60 d,髁突宽度(Q-R)变短,有统计学差异(P<0. 05)。在30 d和60 d,TIPA实验组髁突的后表面变平。在整个观察期间(60 d),下颌基骨的长度(A-B)和从点C,F到GH的距离,TIPA实验组和对照组无统计学差异(P>0. 05)。结论:TIPA能有效抑制生长期大鼠髁突长度和下颌长度的生长。

Objective: To investigate the morphological effects of Twin Inclined Plane Appliance(TIPA)on the different parts of mandible in growing rats.Methods: The self-designed TIPA was used to induce backward movement of mandible in 6-week-old rats. The morphology of different parts of mandible on 3, 14, 30 and 60 days were measured in experimental and control groups.Results: The mandibular length(A-F), the length of condylarprocess(B-F) and the length of condyle(C-D) were significantly decreased on day 30 and remained so on day 60 in the experimental group. The angle of condylar process axis to mandibular plane(BF/GH) increased significantly on day 30(P<0. 01). On day 60, the width of condyle(Q-R) was decreased significantly in the experimental group(P<0. 05). On day 30 and 60, the posterior surface of the condyle became flattenedin the experimental group. During the whole observation period(60 days), the length of mandibular base(A-B), the distance from point C to GH line and the distance from point F to GH line showed no significant differences between the experimental and control groups(P>0. 05).Conclusions: TIPA can effectively inhibit the growth of condylar length and mandibular length in growing rats.