Fan P, Nicholls J I, Kois J C
Department of Restorative Dentistry, School of Dentistry, University of Washington, Seattle 98195, USA.
Int J Prosthodont. 1995 May-Jun;8(3):213-20.
Twenty-five freshly extracted maxillary first premolars were divided equally among five modalities for rebuilding structurally compromised premolars. These modalities were: (A) buccal stainless steel Parapost/amalgam core, (B) palatal stainless steel parapost/amalgam core, (C) two stainless steel Paraposts/amalgam core, (D) two regular Link Plus TMS single-shear Minim pins/amalgam core, and (E) palatal cast gold post and core. Load fatigue was used as the testing protocol, using a 5.2-kg load applied at 72 cycles per minute. Each tooth was prepared with a 1.0-mm ferrule, and an upper limit of 250,000 load cycles was set for the testing. Two failures were exhibited, (1) preliminary failure which involved a crack in the luting cement layer, and (2) catastrophic failure wherein the core and crown separated from the root section. Statistical analysis using Kruskal-Wallis test showed three subsets (P < or = .05). The subset with the highest number of load cycles to failure contained the palatal stainless steel post/amalgam core, two stainless steel Paraposts/amalgam core, and palatal cast gold post and core.
25颗新鲜拔除的上颌第一前磨牙被平均分为五组，用于重建结构受损的前磨牙。这些方法包括：(A) 颊侧不锈钢桩核/汞合金核，(B) 腭侧不锈钢桩核/汞合金核，(C) 两个不锈钢桩核/汞合金核，(D) 两个常规Link Plus TMS单剪切微型桩/汞合金核，以及(E) 腭侧铸造金桩核。采用负载疲劳作为测试方案，以每分钟72次循环的频率施加5.2千克的负载。每颗牙齿制备1.0毫米的箍套，测试设定的负载循环上限为250,000次。出现了两种失败情况，(1) 初期失败，涉及粘结水门汀层出现裂缝，(2) 灾难性失败，即核与冠从牙根部分分离。使用Kruskal-Wallis检验进行统计分析显示有三个亚组（P≤0.05）。失败时负载循环次数最多的亚组包括腭侧不锈钢桩/汞合金核、两个不锈钢桩核/汞合金核以及腭侧铸造金桩核。
