Statement of problem

Newly developed translucent zirconia materials have been used for anterior monolithic complete coverage restorations. Surface treatments can improve adhesion, as well as decrease or increase the strength of ceramics. However, information on the influence of surface treatments on the strength of translucent zirconias is sparse.

Purpose

The purpose of this in vitro study was to measure and characterize the effects of different surface treatments, including airborne-particle abrasion, on the strength of different translucent 4 mol% and 5 mol% yttria-stabilized zirconia materials.

Materials and methods

Disks (N=160) made from 4 types of translucent yttria-stabilized zirconia materials were surface-treated in 4 ways: Control groups were hand-polished with 2000-grit silicon carbide abrasive paper; as-machined; glass bead airborne-particle abraded; and alumina airborne-particle abraded. The biaxial flexural strength was measured by using a piston-on-3-ball test in a universal testing machine. The simple main effects of material type and surface treatment and their interaction on biaxial flexural strength were evaluated with 2-way ANOVA (α=.05). A priori, 1-way ANOVA and the Tukey multiple comparisons tests were used within material and treatment types (α=.05). Surface morphology was assessed by using scanning electron microscopy. Translucency, absolute transmittance, was measured by using a spectrophotometer.

Results

Two-way ANOVA revealed that the effects of zirconia type, surface treatment, and their interaction all significantly affected biaxial flexural strength (P<.001). One-way ANOVA revealed that the 4Y material was stronger than all 5Y materials, regardless of surface treatment; all 5Y materials were ranked from strongest to weakest as polished; as-machined, or glass bead abraded; and alumina abraded. The 4Y material was stronger when alumina abraded than when glass bead abraded. Scanning electron microscopy showed that as-polished surfaces were smoother than all others; as-machined and glass bead abraded surfaces displayed little difference; alumina abraded was the roughest; and differences among materials were not discerned. The 1-way ANOVA and multiple comparisons testing showed that the 4Y material had less absolute transmittance, approximately 5% less, than all the 5Y materials.

Conclusions

Zirconia material type and surface treatment influenced the strength of translucent zirconia materials; a 4 mol% zirconia material was stronger than 5 mol% zirconia materials for all surface treatments tested; airborne-particle abrasion using alumina had a slight strengthening effect on a 4 mol% zirconia but had a weakening effect on 5 mol% materials; airborne-particle abrasion by using alumina produced the roughest surfaces on all materials; and the 4 mol% material was slightly less translucent than the 5 mol% materials.

中文翻译：

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氧化钇含量及表面处理对透光氧化锆材料强度的影响

问题陈述

新开发的半透明氧化锆材料已用于前牙整体全覆盖修复体。表面处理可以提高附着力，以及降低或增加陶瓷的强度。然而，关于表面处理对半透明氧化锆强度影响的信息很少。

目的

这项体外研究的目的是测量和描述不同表面处理（包括空气颗粒磨损）对不同半透明 4 mol% 和 5 mol% 氧化钇稳定氧化锆材料强度的影响。

材料和方法

由 4 种半透明氧化钇稳定氧化锆材料制成的圆盘 (N=160) 以 4 种方式进行表面处理：对照组用 2000 目碳化硅砂纸手工抛光；机加工；玻璃珠悬浮粒子磨损；和氧化铝空气颗粒磨损。双轴抗弯强度通过在万能试验机中使用三球活塞测试来测量。材料类型和表面处理的简单主效应及其相互作用对双轴抗弯强度的影响使用 2 向方差分析 (α=.05) 进行评估。先验、单向方差分析和 Tukey 多重比较测试用于材料和处理类型 (α=.05)。通过使用扫描电子显微镜评估表面形态。使用分光光度计测量半透明度，绝对透射率。

结果

双向方差分析表明，氧化锆类型、表面处理及其相互作用的影响都显着影响双轴抗弯强度 ( P<.001). 单向方差分析表明，无论表面处理如何，4Y 材料都比所有 5Y 材料更坚固；所有 5Y 材料都按照抛光时从最强到最弱的顺序排列；加工状态，或玻璃珠磨损；和氧化铝磨损。4Y 材料在氧化铝磨损时比在玻璃珠磨损时更坚固。扫描电子显微镜显示抛光后的表面比其他所有表面都光滑；加工表面和玻璃珠研磨表面几乎没有区别；氧化铝磨损最粗糙；材料之间的差异没有被辨别出来。单向方差分析和多重比较测试表明，4Y 材料的绝对透光率低于所有 5Y 材料，大约低 5%。

结论

氧化锆材料类型和表面处理影响透光氧化锆材料的强度；对于所有测试的表面处理，4 mol% 的氧化锆材料比 5 mol% 的氧化锆材料更坚固；使用氧化铝的空气颗粒磨损对 4 mol% 的氧化锆有轻微的强化作用，但对 5 mol% 的材料有弱化作用；使用氧化铝的空气颗粒磨损在所有材料上产生了最粗糙的表面；4 mol% 材料的半透明性略低于 5 mol% 材料。