A new method to test the fracture probability of all-ceramic crowns with a dual-axis chewing simulator
A new method to test the fracture probability of all-ceramic crowns with a dual-axis chewing simulator
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DOI：
10.1016/j.dental.2010.09.004
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发表时间：
2011-02-01
期刊：
影响因子：
5
通讯作者：
Steiner, M.
中科院分区：
文献类型：
--
作者：
Heintze, S. D.;Albrecht, T.;Steiner, M.
目标。本研究的目的是验证一种新的实验室方法来测试全瓷系统的失败率。16个标准下颌磨牙冠，由两种不同材料(IPS Empress和IPS e.max Press)组成，粘接在CAD/CAM加工的PMMA基牙(第一下磨牙，圆形倒角)上。所有的冠在Willytec咀嚼模拟器上施加偏心力(钢笔，空置2.4 mm，从牙窝到尖尖横向移动2 mm)，逐步增加载荷(3，5，9 kg，每个循环100,000次，0.8赫兹)和同时热循环(5℃/55℃×417每相)。每种材料的另外四个冠在每个加载阶段使用两种不同的横向运动(从牙窝到牙尖和从牙尖到牙尖)进行动态加载时，用三维力传感器进行测力。与咀嚼模拟器的静载荷(3 kg 60N、5 kg 160N、9 kg 240N)相比，空间三个方向的累积作用力要大得多。两种材料或两种不同侧向运动的平均或最大力差异无统计学意义。在动态加载过程中，IPSe.max Press制作的磨牙全冠没有发生折裂，而IPS Empress全冠有50%的折裂(75%的折裂和25%的碎屑)(对数检验p=0.002)。大部分皇后冠在第三次加载时折断(9 Kg)。动荷载作用下的自重作用力是静荷载作用下的2-3倍。在动态加载过程中，二硅酸锂陶瓷磨牙冠无一例折断，而白榴石增强磨牙冠有一半失效。(C)2010年牙科材料学会。爱思唯尔有限公司出版。保留所有权利。
Objectives. The purpose of this study was to validate a new laboratory method to test all-ceramic systems with regard to the proportion of failures.Methods. Sixteen standardized mandibular molar crowns consisting of two different materials (IPS Empress, IPS e.max Press) were adhesively luted on CAD/CAM milled PMMA abutments (first lower molar, circular chamfer). All crowns were loaded applying an eccentric force in a Willytec chewing simulator (steel stylus, empty set 2.4 mm, 2 mm lateral movement from fossa to cuspal tip) with stepwise increase of the load (3, 5, 9 kg, 100,000 cycles each, 0.8 Hz) and simultaneous thermocycling (5 degrees C/55 degrees C x 417 per phase). Another four crowns of each material were subjected to force measurements with a 3D force sensor during dynamic loading of each loading phase using two different lateral movements (from fossa to cusp and vice versa).Results. The cumulative forces for the three directions in space were much higher compared to the static load of the chewing simulator (maximal force at 3 kg 60 N, 5 kg 160 N, 9 kg 240 N). There was no statistically significant difference in the mean or maximal force between the two materials or two different lateral movements. During dynamic loading, no fractures occurred in the molar crowns made of IPS e.max Press, whereas 50% of the IPS Empress crowns showed failures (75% fractures and 25% chippings) (log-rank test p = 0.002). Most of the Empress crowns fractured during the third loading phase (9 kg).Conclusions. The forces that the dead weights exerted during dynamic loading were 2-3 times higher than those during static loading. None of the lithium disilicate ceramic molar crowns fractured, whereas half of the leucite reinforced molar crowns failed during dynamic loading. (C) 2010 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.