Abstract:

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；cast- structured base，n = 71）.  ARI was recorded in all bracket bases and some bases were chosen randomly and analysed by scanning electron microscope（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.

Key words: bracket base；bond strength；adhesive remnant index, ARI；enamel damage

摘要：

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。

关键词: 托槽底板, 粘接强度, 粘接剂残余指数, 釉质损伤