Scherrer Susanne S, Wiskott Anselm H W, Coto-Hunziker Viviana, Belser Urs C
School of Dental Medicine, University of Geneva, Switzerland.
J Prosthet Dent. 2003 Jun;89(6):579-88. doi: 10.1016/s0022-3913(03)00174-4.
Ordinarily, the mechanical strength of composites is characterized by their flexural strength. Information as to the material's fatigue strength is seldom provided.
The purpose of this study was to compare the flexural strength and the resistance to fatigue loading of composites and an acrylic resin for provisional and definitive restorations.
Artglass, Colombus, and Targis (composites) and Jet, Protemp II, Protemp Garant, and Provipont DC (provisional restorations) were subjected to mechanical tests. Fatigue tests (MPa) (n = 30 specimens/group) were conducted with the rotating-bending cantilever design. Monotonic flexural strength (MPa) (n = 10) was determined in 3-point bending tests. Fatigue resistance was analyzed via the staircase procedure, and flexural strength was examined by use of the 2-parameter Weibull distribution (confidence intervals at 95%).
The mean fatigue resistances (S(50)) in MPa +/- SD were: Targis, 62.1 +/- 7.0; Artglass, 58.5 +/- 3.7; Colombus, 54.6 +/- 6.2; Provipont DC, 29.5 +/- 3.2; Protemp II, 23.1 +/- 5.3; Jet, 22.8 +/- 8.3; Protemp Garant, 19.6 +/- 4.6. The flexure strengths (Weibull's S(0)) in MPa and their shape parameters (m) were: Colombus, 145.2 (13.1); Targis, 110.3 (7.8); Artglass, 5.9 (5.4); Jet, 150.9 (17.3); Provipont DC, 97.3 (23.8); Protemp II, 57.9 (6.4); Protemp Garant, 54.2 (12.8). The S(50) of Targis was significantly higher than that of Colombus but not different from Artglass. In flexion, the S(0) of Colombus was significantly higher than that of Artglass and Targis. The S(50) ranged between 40% and 60% of the S(0) for the composites and between 15% and 30% for the provisional restorative materials.
Correlations between monotonic flexure strength and resistance to fatigue loading were weak. Because fatigue tests are considered more pertinent than monotonic tests as to their predictive value, it is concluded that flexure strength data alone may not provide relevant information for long-term clinical performance. The material's resistance to fatigue loading should also be determined.
通常，复合材料的机械强度由其弯曲强度来表征。关于材料疲劳强度的信息很少提供。
本研究的目的是比较用于临时和最终修复的复合材料与丙烯酸树脂的弯曲强度和抗疲劳载荷能力。
对Artglass、Colombus和Targis（复合材料）以及Jet、Protemp II、Protemp Garant和Provipont DC（临时修复材料）进行机械测试。采用旋转弯曲悬臂设计进行疲劳测试（MPa）（每组n = 30个样本）。在三点弯曲试验中测定单调弯曲强度（MPa）（n = 10）。通过阶梯程序分析抗疲劳性，并使用双参数威布尔分布（95%置信区间）检查弯曲强度。
以MPa为单位的平均抗疲劳性（S(50)）及标准差为：Targis，62.1 +/- 7.0；Artglass，58.5 +/- 3.7；Colombus，54.6 +/- 6.2；Provipont DC，29.5 +/- 3.2；Protemp II，23.1 +/- 5.3；Jet，22.8 +/- 8.3；Protemp Garant，19.6 +/- 4.6。以MPa为单位的弯曲强度（威布尔S(0)）及其形状参数（m）为：Colombus，145.2（13.1）；Targis，110.3（7.8）；Artglass，5.9（5.4）；Jet，150.9（17.3）；Provipont DC，97.3（23.8）；Protemp II，57.9（6.4）；Protemp Garant，54.2（12.8）。Targis的S(50)显著高于Colombus，但与Artglass无差异。在弯曲方面，Colombus的S(0)显著高于Artglass和Targis。复合材料的S(50)介于S(0)的40%至60%之间，临时修复材料的S(50)介于15%至30%之间。
单调弯曲强度与抗疲劳载荷之间的相关性较弱。由于就预测价值而言，疲劳测试比单调测试更具相关性，因此得出结论，仅弯曲强度数据可能无法为长期临床性能提供相关信息。还应确定材料的抗疲劳载荷能力。
