Residual interface tensile strength of ceramic bonded to dentin after cyclic loading and aging
Residual interface tensile strength of ceramic bonded to dentin after cyclic loading and aging
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DOI：
10.1016/s0022-3913(08)60045-1
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发表时间：
2008-03-01
影响因子：
4.6
通讯作者：
Seghi, Robert R.
中科院分区：
文献类型：
--
作者：
Hernandez, Alfredo I.;Roongruangphol, Thasanai;Seghi, Robert R.
问题陈述。为了防止牙尖骨折的潜在风险，美观的全颌修复体一直被提倡用于大修复体的牙齿。胶粘剂树脂水泥的影响被认为在加强这些修复中起作用。牙齿/粘接剂/陶瓷界面的耐久性对确保临床寿命至关重要。本研究的目的是评估循环载荷和环境老化对陶瓷与牙本质结构结合的残余界面强度的影响。材料和方法。制作了18个简单的三层标本，包括1.5 mm厚的陶瓷板（ProCAD）与扁平的人臼齿结合，暴露冠状牙本质。使用树脂水泥（Nexus 2）和制造商推荐的粘合技术粘合陶瓷板。将试件分为3组，分别在37℃的水中保存10周作为对照组（CT）， 9个月作为老化组（AG），或放置在37℃的水中，在20 - 200 N之间进行1000万次垂直加载循环作为疲劳组（FG）。在实验条件下，将样品垂直于平坦的陶瓷表面切成1 x 1-mm的棒。每个试样的平均残余界面微拉伸键（MTB）强度仅用那些含有陶瓷粘结到牙本质的棒来测定。采用Welbull分析方法对MTB强度数据进行分析，确定组间差异。所有随后失效的试样表面在x 10倍放大的立体显微镜下进行评估，以确定明显的失效模式。在扫描电子显微镜（SEM）下，从每个失效模式类别中选取一些样品进行表面评价。3组的特征Welbull均值分别为CT 19.2, FG 14.7, AG 11.7。CT组黏结强度均显著高于AG组（P= 0.007）和FG组（P= 0.014）。光镜下的破坏模式分类表明，在所有3组中，陶瓷/水泥界面的粘结破坏最为常见（65%）。对各组所选试样的失效表面进行扫描电镜评价，无法区分出任何界面外观差异。对于间接粘接剂保留的陶瓷修复体，循环咀嚼载荷和水解降解都可能导致界面键的减弱。随着时间的推移，陶瓷/树脂界面可能比牙本质/树脂界面更容易受到这些变化的影响。
Statement of problem. To guard against the potential risk of cusp fracture, esthetic onlay restorations have been advocated for teeth with large restorations. The influence of the adhesive resin cement is believed to play a role in strengthening these restorations. The durability of this tooth/adhesive/ceramic interface is critical to ensure clinical longevity.Purpose. The purpose of this study was to assess the effects of cyclic loading and environmental aging on the residual interface strength of a ceramic bonded to dentin structure.Material and methods. Eighteen simple trilayer specimens were fabricated, consisting of a 1.5-mm-thick ceramic plate (ProCAD) bonded to a flattened human molar tooth with exposed coronal dentin. The ceramic plates were bonded using resin cement (Nexus 2) and manufacturer-recommended bonding techniques. The specimens were divided into 3 equal groups and were stored in water at 37 degrees C for 10 weeks as a control group (CT), 9 months as an aging group (AG), or placed in water at 37 degrees C while being subjected to 10 million vertical loading cycles between 20 N to 200 N, as a fatigue group (FG). After the specimens were subjected to the experimental conditions, they were sectioned perpendicular to the flat ceramic surface into 1 x 1-mm sticks. The mean residual interface microtensile bond (MTB) strength was determined for each specimen using only those sticks which contained ceramic bonded to dentin. The MTB strength data were analyzed using Welbull analysis methods to determine differences between groups. All subsequent failed specimen surfaces were evaluated under a stereomicroscope at x 10 magnification to determine the apparent failure modes. Some specimens were selected from each failure mode category for surface evaluation under a scanning electron microscope (SEM).Results. The characteristic Welbull means for the 3 groups were CT, 19.2, FG, 14.7, and AG, 11.7. The bond strength of group CT was significantly greater than both AG (P=.007) and FG (P=.014). Light microscopic categorization of the failure modes suggests that adhesive failure at the ceramic/cement interface was the most common (65%) for all 3 groups. SEM evaluation of failed surfaces of select specimens from each group could not distinguish any interface appearance differences.Conclusions. For indirect adhesive-retained ceramic restorations, both cyclic masticatory loading and hydrolytic degradation may contribute to a weakening of the interface bond. The ceramic/resin interface may be more susceptible to these changes over the time frame of this investigation than the dentin/resin interface.