Objectives

To assess the shear bond strength (SBS) between metal orthodontic brackets and zirconia after receiving different mechanical and chemical surface treatments, and different types of resin adhesive. The failure mode of each treatment protocol was also evaluated.

Materials and methods

The present in vitro experimental study consisted of six surface treatment protocols with two different resin adhesives. One-hundred and forty-four rectangular-shaped 3 mol% yttrium-stabilized tetragonal zirconia polycrystal blocks were milled, sintered, and embedded in acrylic resin. They were randomly divided into three mechanical (none, air abrasion, and bur grinding) and two chemical surface treatment conditions (no primer and Z-primer). The specimens were divided into two groups according to the resin adhesive received: self-cured (RelyX U200) and light-cured adhesives (Transbond XT). The SBS between the metal bracket and zirconia was tested using a universal testing machine (1-mm/min crosshead speed), and the failure mode was evaluated. Differences in SBS and failure mode were analyzed using Welch ANOVA followed by post-hoc comparison and Fisher’s Exact test, respectively.

Results

Bur grinding produced the highest SBS, followed by air abrasion. Z-primer application typically provided a higher SBS regardless of resin adhesive used (p < 0.001). Without primer application, RelyX U200 provided a higher SBS than Transbond XT (p < 0.001). After grinding, using Z-primer and RelyX U200 resulted in a higher SBS than no primer and using Transbond XT (p < 0.001). Adhesive failure at the zirconia–adhesive interface occurred only when Transbond XT was applied without bur grinding, and when using Transbond XT after grinding, but no Z-primer application.

Conclusion

Bur grinding combined with applying an MDP-containing primer and resin adhesive enhances the SBS between zirconia and metal orthodontic brackets.

中文翻译：

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机械和化学表面处理增强氧化锆和正畸托槽之间的粘合强度：一项体外研究

目标

评估金属正畸托槽与氧化锆在接受不同的机械和化学表面处理以及不同类型的树脂粘合剂后的剪切粘合强度（SBS）。还评估了每种治疗方案的失败模式。

材料和方法

目前的体外实验研究包括使用两种不同树脂粘合剂的六种表面处理方案。将 144 个矩形 3 mol% 钇稳定的四方氧化锆多晶块研磨、烧结并嵌入丙烯酸树脂中。它们被随机分为三种机械表面处理条件（无、空气磨损和毛刺研磨）和两种化学表面处理条件（无底漆和 Z 底漆）。根据所接受的树脂粘合剂将样品分为两组：自固化粘合剂（RelyX U200）和光固化粘合剂（Transbond XT）。使用万能试验机（1毫米/分钟十字头速度）测试金属支架和氧化锆之间的SBS，并评估失效模式。使用 Welch ANOVA 分析 SBS 和失效模式的差异，然后分别进行事后比较和 Fisher 精确检验。

结果

车针磨削产生的 SBS 最高，其次是空气磨削。无论使用何种树脂粘合剂，Z 底漆应用通常都能提供更高的 SBS ( p  < 0.001)。在不涂底漆的情况下，RelyX U200 提供的 SB​​S 高于 Transbond XT ( p  < 0.001)。研磨后，使用 Z-primer 和 RelyX U200 产生的 SBS 高于无底漆和使用 Transbond XT ( p  < 0.001)。仅当在未进行毛刺研磨的情况下使用 Transbond XT 以及在研磨后使用 Transbond XT 但未使用 Z 底漆时，才会发生氧化锆-粘合剂界面处的粘合失效。

结论

车针研磨与涂敷含 MDP 的底漆和树脂粘合剂相结合，可增强氧化锆和金属正畸托槽之间的 SBS。