Braga R R, Cesar P F, Gonzaga C C
Department of Dental Materials, School of Dentistry, University of São Paulo, São Paulo, Brazil.
J Oral Rehabil. 2002 Mar;29(3):257-62. doi: 10.1046/j.1365-2842.2002.00821.x.
Dual-cured cements have been studied in terms of the hardness or degree of conversion achieved with different curing modes. However, little emphasis is given to the influence of the curing method on other mechanical properties. This study investigated the flexural strength, flexural modulus and hardness of four proprietary resin cements. Materials tested were: Enforce and Variolink II (light-, self- and dual-cured), RelyX ARC (self- and dual-cured) and C & B (self-cured). Specimens were fractured using a three-point bending test. Pre-failure loads corresponding to specific displacements of the cross-head were used for flexural modulus calculation. Knoop hardness (KHN) was measured on fragments obtained after the flexural test. Tests were performed after 24 h storage at 37 degrees C. RelyX ARC dual-cured showed higher flexural strength than the other groups. RelyX ARC and Variolink II depended upon photo-activation to achieve higher hardness values. Enforce showed similar hardness for dual- and self-curing modes. No correlation was found between flexural strength and hardness, indicating that other factors besides the degree of cure (e.g. filler content and monomer type) affect the flexural strength of composites. No statistical difference was detected in the flexural modulus among the different groups.
针对双固化水门汀，人们已就不同固化模式下所达到的硬度或固化程度展开了研究。然而，对于固化方法对其他机械性能的影响却鲜有重视。本研究调查了四种专利树脂水门汀的弯曲强度、弯曲模量和硬度。所测试的材料有：Enforce和Variolink II（光固化、自固化和双固化）、RelyX ARC（自固化和双固化）以及C & B（自固化）。使用三点弯曲试验使样本断裂。对应于十字头特定位移的失效前载荷用于计算弯曲模量。在弯曲试验后获得的碎片上测量努氏硬度（KHN）。试验在37℃下储存24小时后进行。RelyX ARC双固化显示出比其他组更高的弯曲强度。RelyX ARC和Variolink II依赖光活化来获得更高的硬度值。Enforce在双固化和自固化模式下显示出相似的硬度。未发现弯曲强度与硬度之间存在相关性，这表明除固化程度之外的其他因素（例如填料含量和单体类型）会影响复合材料的弯曲强度。不同组之间的弯曲模量未检测到统计学差异。
