Statement of problem

There is little evidence on how the multiple layers of zirconia (ZrO₂) or glazed material will affect the shear bond strength (SBS) of different resin cements.

Purpose

The purpose of this in vitro study was to compare the SBS of 2 resin cements with the different layers of a monolithic polychromatic ZrO₂ ceramic, both glazed and nonglazed, and a lithium disilicate (LDS) ceramic.

Material and methods

One hundred and sixty-eight composite resin cylinders and 48 monolithic polychromic ZrO₂ plates were prepared. Twenty-four were milled and sintered, and 24 were milled and sintered and had a glaze cycle applied with no liquid glaze. These plates and 12 LDS plates were mounted in autopolymerized acrylic resin. Bonding surfaces were polished, airborne-particle abraded, and cleaned ultrasonically. The different layers (cubic, hybrid, and tetragonal) of the ZrO₂ plates were identified and marked. The plates were assigned to 2 cement groups: a self-adhesive, autopolymerized resin cement, and a dual-polymerizing, adhesive resin cement (DPRC). Bonding surfaces were cleaned and treated according to the cement manufacturer’s instructions. Three composite resin cylinders were luted to the ZrO₂ plates at the appropriate layer, and 2 cylinders were luted to each LDS plate. The specimens were stored in a moist environment for 24 hours at 37 °C. The SBS test was performed with a universal testing machine. Visual inspections of the debonded surfaces were compared under magnification. The data were analyzed with a 2-way ANOVA and a subsequent Student t test (α=.05).

Results

The 2-way ANOVA found no difference among luting agent and LDS and ZrO₂. The SBSs of the nonglazed tetragonal and cubic layer to the ZrO₂ were higher than to the surface exposed to a glazing cycle (P=.001). The bonded surfaces were examined tactilely and under ×3.5 magnification, followed by light and scanning electron microscopy and recorded as either adhesive, cohesive, or mixed. Almost all failures in the glazed ZrO₂ were mixed and cohesive. However, more adhesive failures were observed in the DPRC group of nonglazed ZrO₂.

Conclusions

No differences were found between the 2 luting agents for the LDS. For the ZrO₂ cubic and tetragonal layers, the DPRC had higher bond strengths to the nonglazed surfaces.

中文翻译：

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两种树脂水泥对氧化锆和二硅酸锂的体外剪切粘结强度：体外研究

问题陈述

几乎没有证据表明氧化锆（ZrO ₂）或玻璃材料的多层会如何影响不同树脂水泥的剪切粘结强度（SBS）。

目的

这项体外研究的目的是比较两种树脂水泥与单层多色ZrO ₂ 陶瓷（釉面和非釉面）以及二硅酸锂（LDS）陶瓷的不同层的SBS 。

材料与方法

 制备了168个复合树脂圆柱体和48个整体式多色ZrO ₂板。研磨和烧结二十四个，并且研磨和烧结二十四个，并且施加了没有液体釉的釉循环。将这些板和12个LDS板安装在自聚丙烯酸树脂中。粘合表面被抛光，空气中的颗粒被研磨，并被超声波清洗。 标识并标记了ZrO ₂板的不同层（立方层，杂层和四边形）。这些板分为2组：自粘自聚合树脂胶和双聚合粘树脂胶（DPRC）。根据水泥制造商的说明清洁和处理粘结面。将三个复合树脂圆柱体插入ZrO在适当的层上放置_2个板，并将2个圆柱体浸入每个LDS板上。将样品在潮湿的环境中于37°C下保存24小时。SBS测试是在通用测试机上进行的。在放大下比较脱粘表面的目视检查。数据用2通ANOVA和随后的Student t检验（α= .05）进行分析。

结果

在两向方差分析中发现诱变剂与LDS和ZrO ₂之间没有差异。ZrO ₂的无釉方形和立方层的SBS高于暴露于上釉周期的表面的SBS （P = .001）。触觉检查粘合表面，并在×3.5放大倍率下进行检查，然后进行光镜和扫描电子显微镜检查，并记录为胶粘剂，内聚剂或混合剂。釉面ZrO ₂中几乎所有的缺陷都是混合的和粘结的。但是，在非釉面ZrO ₂的DPRC组中观察到了更多的粘合失败。

结论

LDS的两种诱剂之间没有发现差异。对于ZrO ₂ 立方层和四方层，DPRC与非釉面的结合强度更高。