不同底板托槽拆除后底板残余粘接剂分析

Analysis of bracket base remnant after removing brackets of different bases

目的比较激光和铸造2种底板托槽的粘接强度,分析托槽底板残余物,探讨拆除托槽对釉质表面的影响。方法选取2014年6月于哈尔滨医科大学口腔颌面外科因正畸拔除的上颌前磨牙40颗,其中选择激光底板和铸造底板托槽各20颗,粘接于离体上颌前磨牙后进行剪切、拉伸实验。再选取正畸结束患者拆除的前磨牙激光底板、铸造底板托槽各71个,对所有托槽底板粘接剂残余指数(ARI)进行计分,并随机抽取托槽进行底板粘接剂电镜观察。结果激光底板托槽抗剪切强度(SBS)和ARI高于铸造底板托槽,抗拉伸强度(TBS)低于铸造底板托槽(P<0.05);托槽底板残余粘接剂中均可检测到钙元素。结论激光和铸造两种底板托槽的粘接强度均能达到临床要求,拆除托槽对釉质表面有损伤。

Objective To evaluate the bond strength of two-base brackets , analyse the bracket base remnant and the effect on enamel surface after brackets were removed. Methods The laser-structured base （n = 20）and cast-structured base （n = 20）brackets were bonded on the surfaces of extracted maxillary premolars and the SBS, TBS tested. Premolar brackets were from patients who finished orthodontic treatment （laser-structured base, n = 71 ; caststructured base, n = 71 ）. ARI was recorded in all bracket bases and some bases were chosen randomly and analysed by scanning electron mi croscope （SEM）. Results The SBS and ARI of laser-structured base brackets were higher than cast-structured base brackets, but the TBS was lower （P 〈 0.05）. Each bracket base remnant was found to have Ca element. Conclusion The bond strengths of the two brackets are enough for clinical application ; enamel damage occurs during removing.