Lopes Gustavo Vallandro, Correr-Sobrinho Lourenço, Correr Américo Bortolazzo, Godoi Ana Paula Terossi de, Vedovello Silvia Amélia Scudeler, Menezes Carolina Carmo de
Departament of Orthodontics, Centro Universitário da Fundação Hermínio Ometto -FHO, Araras, SP, Brazil.
Departamento of Restorative Dentistry, Dental Materials, UNICAMP - Universidade Estadual de Campinas, Piracicaba, SP, Brazil.
Braz Dent J. 2020 Jan-Feb;31(1):52-56. doi: 10.1590/0103-6440202003101.
The present study was evaluated the effect of different light activation and thermocycling methods on the shear bond strength (SBS) and on the adhesive remnant index (ARI) of metal brackets bonded to feldspathic ceramic. Hundred metal brackets were bonded to 20 porcelain cylinders, divided into four groups (n=25) based on light activation and thermocycling processes. The cylinders were etched with 10% hydrofluoric acid for 60 s and coated with two layers of silane. The brackets were bonded with Transbond XT composite resin. Light activation in Groups 1 and 3 was performed during 3 s using the VALO Ortho Cordless appliance with irradiance 3,200 mW/cm2 and in Groups 2 and 4 for 40 s using Optilight Max appliance with irradiance 1,200 mW/cm². The samples were stored in deionized water at 37°C for 24 h and the samples from Groups 1 and 2 were submitted to the SBS test at a rate of 1 mm/min, whereas the samples from Groups 3 and 4 were submitted to 7,000 thermal cycles (5°/55°C) before to the SBS test. The data were assessed by two-way analysis of variance and by Tukey's test (a=0.05). No significant difference was observed between SBS means in the different light activation devices used. The samples subjected to thermocycling revealed lower SBS values (p≤0.05). There was predominance of score 0 for ARI in all groups. Therefore, the different light activation methods did not interfere in SBS, but thermocycling reduced SBS.
本研究评估了不同光激活和热循环方法对粘结在长石质陶瓷上的金属托槽的剪切粘结强度（SBS）和粘结残余指数（ARI）的影响。将100个金属托槽粘结到20个瓷柱上，根据光激活和热循环过程分为四组（n = 25）。瓷柱用10%氢氟酸蚀刻60秒，然后涂覆两层硅烷。托槽用Transbond XT复合树脂粘结。第1组和第3组使用VALO Ortho无绳器械进行3秒的光激活，辐照度为3200 mW/cm²，第2组和第4组使用Optilight Max器械进行40秒的光激活，辐照度为1200 mW/cm²。样本在37°C的去离子水中储存24小时，第1组和第2组的样本以1 mm/min的速率进行SBS测试，而第3组和第4组的样本在进行SBS测试前先进行7000次热循环（5°/55°C）。数据通过双向方差分析和Tukey检验进行评估（α = 0.05）。在所使用的不同光激活装置的SBS平均值之间未观察到显著差异。经过热循环的样本显示出较低的SBS值（p≤0.05）。所有组的ARI得分以0分占主导。因此，不同的光激活方法不会干扰SBS，但热循环会降低SBS。
