Mirmohammadi Hesam, Kleverlaan Cornelis J, Aboushelib Moustafa N, Feilzer Albert J
Department of Dental Materials Science, Academic Center for Dentistry Amsterdam, University of Amsterdam, The Netherlands.
Am J Dent. 2011 Feb;24(1):31-6.
To evaluate the effect of enzymatic activity and alkaline medium on flexural strength and rotary fatigue resistance of direct and indirect resin composite restorative materials.
Three direct resin composite materials Filtek Z100, Filtek Z250 and Filtek Silorane (3M ESPE), and two indirect resin composite materials; Sinfony (3M ESPE) and an experimental composite (Heraeus Kulzer) were used to fabricate bar-shaped specimens (2 x 2 x 25 mm; n=10) to determine the flexural strength (Fs) by means of a 3-point bending test according to ISO 4049. Additional specimens of the same dimensions (n=20) were used to prepare hour-glass shaped specimens which were immersed in distilled water for 48 hours, transferred to one of five aqueous media at 37 degrees C for 2 weeks; phosphate buffer, distilled water, 0.1N NaOH, 1 unit/ml Amylase, 0.1 unit/ml Esterase, and a group in 0.1N NaOH at 60 degrees C. Rotary fatigue resistance (RFR) was determined in a rotating-bending cantilever test with the highest stress located at the constriction of the hour glass. The rotary fatigue resistance tests were conducted according to the staircase approach (10(4) cycles, 1.0 Hz) and the mean RFR was calculated using logistic regression analysis.
NaOH produced a significant decrease in Fs of all materials. The effect of enzymatic biodegradation on Fs of Filtek Z100 and Filtek Z250 was found to be significant, however, for Silorane and indirect composites it was not significant. Except for NaOH the influence of the different aqueous solutions on RFR was not significant for all tested materials.
评估酶活性和碱性介质对直接和间接树脂复合修复材料的弯曲强度和抗旋转疲劳性的影响。
使用三种直接树脂复合材料Filtek Z100、Filtek Z250和Filtek Silorane（3M ESPE），以及两种间接树脂复合材料；Sinfony（3M ESPE）和一种实验性复合材料（贺利氏古莎）制作条形试件（2×2×25mm；n = 10），根据ISO 4049通过三点弯曲试验确定弯曲强度（Fs）。使用相同尺寸的额外试件（n = 20）制备沙漏形试件，将其浸入蒸馏水中48小时，转移至37℃的五种水性介质之一中2周；磷酸盐缓冲液、蒸馏水、0.1N NaOH、1单位/毫升淀粉酶、0.1单位/毫升酯酶，以及一组在60℃的0.1N NaOH中。在旋转弯曲悬臂试验中测定抗旋转疲劳性（RFR），最大应力位于沙漏形的缩颈处。旋转疲劳抗性试验按照阶梯法（10⁴ 次循环，1.0 Hz）进行，并使用逻辑回归分析计算平均RFR。
NaOH使所有材料的Fs显著降低。发现酶促生物降解对Filtek Z100和Filtek Z250的Fs有显著影响，然而，对于Silorane和间接复合材料则不显著。除NaOH外，不同水溶液对所有测试材料的RFR影响不显著。
