In vitro analysis of shear bond strength and adhesive remnant index of different metal brackets

ABSTRACT Introduction: There is a great variety of orthodontic brackets in the Brazilian market, and constantly evaluating them is critical for professionals to know their properties, so as to be able to choose which product best suits their clinical practice. Objectives: To evaluate the bond strength and the adhesive remnant index (ARI) of different brands of metal brackets. Material and Methods: A total of 105 bovine incisors were used, and brackets of different brands were bonded to teeth. Seven different bracket brands were tested (MorelliTM, American OrthodonticsTM, TP OrthodonticsTM, Abzil-3MTM, OrthometricTM, TecnidentTM and UNIDENTM). Twenty-four hours after bonding, shear bond strength test was performed; and after debonding, the ARI was determined by using an optical microscope at a 10-fold increase. Results: Mean shear bond strength values ranged from 3.845 ± 3.997 (MorelliTM) to 9.871 ± 5.106 MPa (TecnidentTM). The majority of the ARI index scores was 0 and 1. Conclusion: Among the evaluated brackets, the one with the lowest mean shear bond strength values was MorelliTM. General evaluation of groups indicated that a greater number of bond failure occurred at the enamel/adhesive interface.

摘要
引言：巴西市场的正畸托槽品类丰富多样，临床从业者持续对其开展评估，对于了解产品性能、遴选适配临床需求的矫治器材至关重要。
研究目的：评估不同品牌金属托槽的剪切粘接强度及残留粘接剂指数（adhesive remnant index, ARI）。
材料与方法：本研究共纳入105颗牛切牙，将7种不同品牌的金属托槽分别粘接于牙体表面，受试品牌包括MorelliTM、American OrthodonticsTM、TP OrthodonticsTM、Abzil-3MTM、OrthometricTM、TecnidentTM及UNIDENTM。粘接完成24小时后，开展剪切粘接强度测试；托槽脱粘后，采用10倍光学显微镜测定残留粘接剂指数。
结果：各组剪切粘接强度均值范围为3.845±3.997 MPa（MorelliTM）至9.871±5.106 MPa（TecnidentTM）；多数残留粘接剂指数评分为0级与1级。
结论：在所评估的托槽中，MorelliTM的平均剪切粘接强度最低。各组整体评估结果显示，多数粘接失效发生于牙釉质与粘接剂的界面。