Osborne-Smith K L, Burke F J, Farlane T M, Wilson N H
University Dental Hospital of Manchester, UK.
J Dent. 1998 Jul-Aug;26(5-6):427-33. doi: 10.1016/s0300-5712(97)00029-8.
The effect of non-carious cervical lesions (NCCL) on tooth fracture resistance has not previously been investigated. The aims of this in vitro study were to examine the fracture resistance of a group of extracted maxillary premolar teeth with mesio-occlusal-distal (MOD) restorations of amalgam, and restored or unrestored simulated NCCL.
Forty sound maxillary, premolar teeth were divided at random into four groups, each of 10 teeth, which were fixed crown uppermost and long axis vertical in stainless steel moulds. Groups 1,2,3 and 4 were prepared with standardized parallel-sided MOD cavities, then restored with amalgam. Groups 1, 2 and 3 were further prepared with standardized NCCL. The NCCL in Group 1 were restored using a resin-modified polyalkenoate (glass-ionomer) cement, and the NCCL in Group 2 were restored with an adhesive composite resin system. The NCCL in Group 3 were left unrestored. The specimens were loaded compressively at 1 mm min-1 using a universal testing machine.
Mean fracture loads (KN) of 1.08, 1.03, 0.98 and 1.14, respectively, were recorded for Groups 1, 2, 3 and 4. Two-way ANOVA and Scheffe's Multiple Range Test showed no statistically significant difference between the groups.
It is concluded that the presence of a standardized NCCL in an extracted maxillary premolar tooth does not reduce the fracture resistance of the tooth when loaded compressively at 1 mm min-1. The restoration of NCCL with the materials tested did not result in an increase in the fracture resistance of the previously restored premolar teeth, when loaded compressively at 1 mm min-1.
以往尚未研究非龋性颈部病变（NCCL）对牙齿抗折性的影响。本体外研究的目的是检测一组带有银汞合金近中-咬合-远中（MOD）修复体以及存在或不存在模拟NCCL的上颌前磨牙的抗折性。
40颗完好的上颌前磨牙随机分为四组，每组10颗，将其牙冠朝上固定，长轴垂直于不锈钢模具中。第1、2、3和4组制备标准化的平行面MOD洞型，然后用银汞合金修复。第1、2和3组进一步制备标准化的NCCL。第1组的NCCL使用树脂改性聚烯烃酸酯（玻璃离子）水门汀修复，第2组的NCCL用粘结复合树脂系统修复。第3组的NCCL未修复。使用万能试验机以1毫米/分钟的速度对标本进行压缩加载。
第1、2、3和4组的平均抗折载荷（千牛）分别记录为1.08、1.03、0.98和1.14。双向方差分析和谢费多重极差检验显示各组之间无统计学显著差异。
得出结论，当上颌前磨牙以1毫米/分钟的速度进行压缩加载时，存在标准化的NCCL并不会降低牙齿的抗折性。当以1毫米/分钟的速度进行压缩加载时，用测试材料修复NCCL并不会导致先前修复的前磨牙的抗折性增加。
