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目的:比较中老年鼠与青少年鼠牙对正畸力的反应。为中老年人正畸提供实验依据。方法:选用12月龄SD大鼠20只(A组),7周龄SD大鼠20只(B组),以上颌中切牙做支抗,牵引第一磨牙近中移动,分别于加力后3 d、1周、2周、3周随机处死其中的5只大鼠,测量左右侧牙齿移动距离;拍摄X线片;组织学观察,测量压力侧牙周膜的宽度变化;统计压力侧和张力侧成骨细胞、破骨细胞数。比较中老年鼠(A组)与青少年鼠(B组)之间的差别。结果:①牙齿移动距离:加力3 d、1周、2周、3周后,A组牙齿移动距离较B组小(P<0.05)。②牙周韧带宽度:A组在每个时间段均窄于B组,差异均具有显著性(P<0.05)。③成骨细胞及破骨细胞数:两组大鼠均呈现明显的压力区和张力区。加力1周时,A组压力侧破骨细胞明显少于B组,差异有高度显著性(P<0.01);3周时,A组压力侧及张力侧成骨细胞均少于B组,差异有显著性(P<0.05)。结论:正畸力均可使中老年鼠和青少年鼠牙产生移动,但无论是移动速度还是牙周韧带、成骨细胞及破骨细胞的反应,中老年鼠均低于青少年鼠;提示在临床上对中老年病例的正畸过程中要注意力的控制,并关注牙周组织的反应。
Objective: To compare the response of orthodontic force to mouse teeth of middle-aged and young rats. Orthodontics for the elderly to provide experimental evidence. Methods: Twenty (12) SD rats (group A) and 20 SD rats (group B) at 7 weeks old were selected. The maxillary central incisors were used as the anchors and the first molars were pulled proximally. After the force was applied Three rats were randomly sacrificed at 3 d, 1 week, 2 weeks and 3 weeks to measure the left and right tooth movement distance. X-ray films were taken and the histological changes were observed. Tension side of osteoblasts, osteoclasts. Differences between middle aged rats (group A) and young rats (group B) were compared. Results: (1) Teeth movement distance: The tooth movement distance in group A was smaller than that in group B (P <0.05) after 3 days, 1 week, 2 weeks and 3 weeks. ② periodontal ligament width: group A was narrower than group B in each time period, the difference was significant (P <0.05). ③ osteoblasts and osteoclasts: two groups of rats showed significant pressure zone and tension zone. At 1 week, the pressure-side osteoclasts in group A were significantly less than that in group B, the difference was highly significant (P <0.01); at 3 weeks, the pressure side and tension side osteoblasts in group A were less than those in group B, The difference was significant (P <0.05). Conclusion: The orthodontic force can make the rat teeth move in middle-aged and adolescent rats and adolescents, but both the moving speed and the response of periodontal ligament, osteoblast and osteoclast are lower in middle-aged and aged rats than in young rats; On the elderly cases of orthodontic process to pay attention to control, and pay attention to the response of periodontal tissue.