School of Dentistry, Mashhad University of Medical Sciences, Mashhad, Iran.
Eur J Paediatr Dent. 2012 Sep;13(3):197-202.
The aim of this study was to evaluate the efficiency of several surface preparation methods for improving shear bond strength of brackets to demineralised enamel.
in vitro study. Eighty premolars were selected and divided into 5 groups. Group 1 served as the control, while the remaining 4 groups were immersed in a demineralising solution (pH 4.8) for 12 weeks. In groups 1 (control) and 2 (demineralised/control) conventional acid etching was used. In group 3, a solution of 5% sodium hypochlorite (NaOCl) was applied on enamel surface for one minute after acid etching. The brackets in group 4 were bonded with Transbond Plus self-etching primer, and group 5 underwent treatment with a 2% sodium fluoride (NaF) gel, which was applied on the enamel surface for 4 minutes before etching. Shear bond strength (SBS) and adhesive remnant index (ARI) were determined in all groups, and surface morphology was examined under scanning electron microscope (SEM).
The mean SBS of acid-etched demineralised enamel was significantly lower than that of acid-etched sound enamel (p<0.05). Treatment of caries-like lesions with 5% NaOCl or self-etching primer failed to improve the bond strength. After NaF treatment and acid etching of demineralised enamel, both type 1 and type 2 etching patterns were observed and the resulting SBS was comparable to that of sound enamel (p>0.05).
The application of 2% NaF on enamel caries before bracket bonding is an effective way for enhancing the bond strength.
本研究旨在评估几种表面处理方法对提高去矿化釉质托槽粘结强度的效果。
体外研究。选择 80 颗前磨牙，分为 5 组。第 1 组为对照组，其余 4 组浸入脱矿溶液（pH4.8）中 12 周。第 1 组（对照组）和第 2 组（脱矿/对照组）采用常规酸蚀。第 3 组在酸蚀后用 5%次氯酸钠（NaOCl）溶液处理 1 分钟。第 4 组用 Transbond Plus 自酸蚀底漆粘结托槽，第 5 组用 2%氟化钠（NaF）凝胶处理，在酸蚀前将凝胶涂于釉质表面 4 分钟。所有组均测定粘结强度（SBS）和粘结剂残留指数（ARI），并用扫描电子显微镜（SEM）观察表面形态。
酸蚀去矿化釉质的平均 SBS 明显低于酸蚀正常釉质（p<0.05）。用 5%NaOCl 或自酸蚀底漆处理龋损样病变不能提高粘结强度。用 NaF 处理和酸蚀去矿化釉质后，观察到 1 型和 2 型两种蚀刻模式，得到的 SBS 与正常釉质相当（p>0.05）。
在粘结托槽前用 2%NaF 处理釉质龋损是增强粘结强度的有效方法。
