Fracture strength of two oxide ceramic crown systems after cyclic pre-loading and thermocycling
Fracture strength of two oxide ceramic crown systems after cyclic pre-loading and thermocycling
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DOI：
10.1111/j.1365-2842.2005.01604.x
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发表时间：
2006-09-01
影响因子：
2.9
通讯作者：
Nilner, K.
中科院分区：
文献类型：
--
作者：
von Steyern, P. Vult;Ebbesson, S.;Nilner, K.
本研究的目的是调查氧化锆冠的抗折性能，并将结果与临床上已知的材料(氧化铝)制成的反映临床特征的全冠进行比较。制作了60个牙冠，其中30个相同的氧化铝冠和30个相同的氧化锆冠。每组30个，随机分为3组，每组10个冠，分别进行不同的处理：(I)单纯水储存，(Ii)预加载(10000个循环，30-300N，1 Hz)，(Iii)热循环(5-55度，5000个循环)+预加载(10000个循环，30-300N，1 Hz)。随后，所有60个全冠都承受载荷，直到发生折断。骨折有两种类型：完全骨折和部分骨折。断裂强度(N)分别为：组1，氧化铝905/氧化锆975(P=0.38)，组2，氧化铝904/氧化锆1108(P<；0.007)，组3，氧化铝917/氧化锆910(P>；0.05)。氧化铝组的全部骨折发生率更高(P<；0.01)。在这项体外研究的限制范围内，可以得出结论，如果没有任何循环预加载或热循环，氧化锆冠和氧化铝冠在断裂强度上没有差异。然而，断裂模式有显著差异(P=0.01)，表明氧化锆核比氧化铝核更坚固。用氧化锆核制作的全冠在预加载后具有明显更高的断裂强度。
The aim of the present study was to investigate the fracture resistance of zirconia crowns and to compare the results with crowns made of a material with known clinical performance (alumina) in away that reflects clinical aspects. Sixty crowns were made, 30 identical crowns of alumina and 30 of zirconia. Each group of 30 was randomly divided into three groups of 10 crowns that were to undergo different treatments: (i) water storage only, (ii) pre-loading (10 000 cycles, 30-300 N, 1 Hz), (iii) thermocycling (5-55 degrees, 5000 cycles) + pre-loading (10 000 cycles, 30-300 N, 1 Hz). Subsequently, all 60 crowns were subjected to load until fracture occurred. There were two types of fracture: total fracture and partial fracture. Fracture strengths (N) were: group 1, alumina 905/zirconia 975 (P = 0.38); group 2, alumina 904/zirconia 1108 (P < 0.007) and group 3, alumina 917/zirconia 910 (P > 0.05). Total fractures were more frequent in the alumina group (P < 0.01). Within the limitations of this in vitro study, it can be concluded that there is no difference in fracture strength between crowns made with zirconia cores compared with those made of alumina if they are subjected to load without any cyclic pre-load or thermocycling. There is, however, a significant difference (P = 0.01) in the fracture mode, suggesting that the zirconia core is stronger than the alumina core. Crowns made with zirconia cores have significantly higher fracture strengths after pre-loading.