Objectives

To evaluate the effect of ceramic thickness on the fatigue failure load of two zirconia-reinforced lithium silicate (ZLS) glass-ceramics, adhesively cemented to a dentin analogue material.

Methods

Disc-shaped specimens were allocated into 8 groups (n = 25) considering two study factors: ZLS ceramic type (Vita Suprinity — VS; and Celtra Duo — CD), and ceramic thickness (1.0; 1.5; 2.0; and 2.5 mm). A trilayer assembly (ϕ = 10 mm; thickness = 3.5 mm) was designed to mimic a bonded monolithic restoration. The ceramic discs were etched, silanized and luted (Variolink N) into a dentin analogue material. Fatigue failure load was determined using the Staircase method (100,000 cycles at 20 Hz; initial fatigue load ∼60% of the mean monotonic load-to-failure; step size ∼5% of the initial fatigue load). A stainless-steel piston (ϕ = 40 mm) applied the load into the center of the specimens submerged in water. Fractographic analysis and Finite Element Analysis (FEA) were also performed.

Results

The ceramic thickness influenced the fatigue failure load for both ZLS materials: Suprinity (716 N up to 1119 N); Celtra (404 N up to 1126 N). FEA showed that decreasing ceramic thickness led to higher stress concentration on the cementing interface.

Significance

Different ZLS glass-ceramic thicknesses influenced the fatigue failure load of the bonded system (i.e. the thicker the glass ceramic is, the higher the fatigue failure load will be). Different microstructures of the ZLS glass-ceramics might affect the fatigue behavior. FEA showed that the thicker the glass ceramic is, the lower the stress concentration at the tensile surface will be.

中文翻译：

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两种树脂结合的氧化锆增强硅酸锂玻璃陶瓷的疲劳破坏载荷：陶瓷厚度的影响

目标

为了评估陶瓷厚度对两种粘结在牙本质类似材料上的氧化锆增强硅酸锂（ZLS）玻璃陶瓷疲劳破坏载荷的影响。

方法

考虑两个研究因素，将圆盘状样品分为8组（n = 25）：ZLS陶瓷类型（Vita Suprinity-VS； Celtra Duo-CD）和陶瓷厚度（1.0; 1.5; 2.0;和2.5 mm）。设计了一个三层组件（ϕ  = 10毫米；厚度= 3.5毫米）来模拟粘结的整体修复体。将陶瓷圆盘蚀刻，硅烷化并浸入（Variolink N）制成牙本质类似材料。使用阶梯法确定疲劳破坏载荷（在20 Hz时为100,000个周期；初始疲劳载荷约为平均单调失效载荷的60％；步长约为初始疲劳载荷的5％）。的不锈钢活塞（φ  = 40 MM）施加的负载成淹没在水中的试样的中心。分形分析和有限元分析（FEA）也进行了。

结果

陶瓷厚度影响了两种ZLS材料的疲劳破坏载荷：韧性（716 N至1119 N）；Celtra（404 N至1126 N）。FEA表明，减小陶瓷厚度会导致胶结界面上的应力集中更高。

意义

不同的ZLS玻璃陶瓷厚度会影响粘合系统的疲劳破坏负荷（即，玻璃陶瓷越厚，疲劳破坏负荷就越大）。ZLS玻璃陶瓷的不同微结构可能会影响疲劳行为。FEA表明，玻璃陶瓷越厚，拉伸表面的应力集中就越低。