OBJECTIVES to evaluate the probability of survival and failure modes of lithium-disilicate, feldspathic-ceramic, and resin-nanoceramic anterior veneers cemented on dentin analog substrates after sliding-contact step-stress accelerated life testing (SSALT). METHODS A virtual incisor tooth preparation was produced with a reduction of 1.5mm at the incisal edge and of 0.7mm buccally. A .STL file of the preparation was generated and CAD/CAM based G10 dentin-analog material was used for testing. Laminate veneers were milled in three different materials: lithium-disilicate (LDS, E.max CAD), resin-nanoceramic (RN, Lava Ultimate), and feldspathic-ceramic (FELDS, Vita Blocks). SSALT was employed where a spherical indenter contacted the veneer, slided along its interface with G10 to lift off and start a new cycle at 2Hz in water. Qualitative fractography was performed. The probability of survival (90% confidence-bounds) was calculated for several load/cycle missions. RESULTS The probability of survival for a mission of 50,000 cycles decreased from 50 up to 150N equally for all groups and were not different between them. At 200N, the probability of survival was significantly lower for FELDS (10%) compared to RN veneers (41%), whereas LDS presented intermediate values (22%). The characteristic strength of RN (247N) was significantly higher than LDS (149N), and FELDS (151N). In FELDS and LDS, hackles, wake hackles and twist hackles indicated the direction of crack propagation. In RN, hackles were observed. CONCLUSIONS Differences in probability of survival were observed only at 180 and 200N between groups. Failure modes were similar with veneer fracture down to the tooth-analog substrate.

中文翻译：

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整体式CAD / CAM层压胶合板：可靠性和失效模式。

目的评估在滑动接触式步进应力加速寿命试验（SSALT）后胶结在牙本质类似基质上的二硅酸锂，长石瓷和树脂-纳米陶瓷前饰板的存活和破坏模式的可能性。方法制作一个虚拟的切牙准备，切牙边缘切牙1.5mm，颊侧切牙0.7mm。生成了.STL文件的准备文件，并将基于CAD / CAM的G10牙本质类似物材料用于测试。层压薄板用三种不同的材料研磨：二硅酸锂（LDS，E.max CAD），树脂纳米陶瓷（RN，Lava Ultimate）和长石陶瓷（FELDS，Vita Blocks）。使用SSALT时，球形压头与贴面接触，沿着贴面与G10的界面滑动以提起并在水中以2Hz频率开始新的循环。进行定性分形术。计算了几次负荷/循环任务的存活概率（90％置信区间）。结果50,000个周期的任务的生存概率在所有组中均从50N降低到150N，并且两组之间没有差异。在200N时，与RN单板（41％）相比，FELDS的存活概率（10％）明显较低，而LDS则为中等值（22％）。RN（247N）的特征强度显着高于LDS（149N）和FELDS（151N）。在FELDS和LDS中，、,和扭曲wake表明了裂纹扩展的方向。在RN中，观察到黑头。结论两组之间仅在180和200 N时观察到存活概率的差异。