年龄对环圈式扩弓器扩弓作用的影响

The effect of age on Helix spring appliance expansion in rats

目的 :应用环圈式扩弓器对不同周龄大鼠进行扩弓 ,分析扩弓的各组成成分在不同年龄的大鼠所占比例的变化 ,并探讨年龄因素对扩弓后矿化沉积速率的影响。方法 :选择雄性SD大鼠 6周龄、15周龄、2 4周龄、5 2周龄各 12只 ,按年龄分组。用直径 0 .4 5mm的不锈钢丝弯制环圈式扩弓器。施力 2 0 0 g进行扩弓 10d。于扩弓前和处死前给所有大鼠四环素灌胃。制作四环素荧光标记不脱钙骨磨片和HE染色切片。 (× 4 0 )倍的荧光显微镜下图像输入计算机进行测量、计算扩弓的四个组成成份 :腭中缝扩张 (Sd-Sd)、牙槽突倾斜和弯曲 (At+b-At+b)、牙齿移位 (Td-Td)、牙齿倾斜 (Tt-Tt)。并测量钙化沉积速率 ,观察组织学变化。结果 :四个年龄组扩弓后牙弓宽度都增加 ,未见显著性差异 (P >0 .0 5 )。 (Sd-Sd)值和占扩弓比率在各年龄组间有明显差异(P <0 .0 1) ,有随年龄的增大而减小的趋势。在 15周龄和 6周龄间未见显著性差异 (P >0 .0 5 )。 (Tt-Tt)值在各年龄组间无显著性差异 (P >0 .0 5 ) ,但占扩弓比率在各年龄组有明显差异 (P <0 .0 1) ,有随年龄的增大而增加的趋势。矿化沉积速率在扩弓大鼠随着年龄的增大而减小。结论 :环圈式扩弓器在生长发育高峰期后一段时间内 ,仍能导致象发育高峰期一样的腭中缝扩张。

AIM:To study the effect of age on Helix spring expansion ratio and calcification deposition velocity in rats.METHODS:12 SD male rats of 6 weeks age,15 weeks age,24 weeks age,52 weeks age were selected respectively.Six rats of every group were used for expansion.The other six for control.Helix springs were made by 0.45 mm diameter stainless steel and produced 200 g force.The expansion lasted 10 days.Tetracycline were injected into rats′ stomach before expansion and sacrifice.Undecalcificated tetracycline labeled bone ground sections and HE stain sections were made.The ground sections were observed under fluorescence microscope.The images were input into computer,measuring four conformations of expansion:suture displacing (S d-S d),alveolar tipping and bending (A t+b -A t+b ), tooth displacing (T d-T d) ,tooth tipping (T t-T t) and. calcification deposition velocity.The tissues of HE stain sections were observed.RESULTS:Four groups arch widths all increased and had no difference ( P >0.05) .(S d-S d) tite and its expansion ratio decreased following age.But no change between 6w and 15w ( P >0.05).(T t-T t) tite changed not apparently ( P >0.05),but its expansion ratio increased following age. The calcification deposition velocity decreased following age.CONCLUSION:During a period beyond growth pubertal Helix spring expansion still resulted in palatal expansion as in growth pubertal.Then the orthopedic effect decreased following age.