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首页> 外文期刊>Journal of Applied Oral Science >The effect of different light-curing units on tensile strength and microhardness of a composite resin
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The effect of different light-curing units on tensile strength and microhardness of a composite resin

机译:不同光固化单元对复合树脂拉伸强度和显微硬度的影响

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摘要

The aim of this study was to evaluate the influence of different light-curing units on the tensile bond strength and microhardness of a composite resin (Filtek Z250 - 3M/ESPE). Conventional halogen (Curing Light 2500 - 3M/ESPE; CL) and two blue light emitting diode curing units (Ultraled - Dabi/Atlante; UL; Ultrablue IS - DMC; UB3 and UB6) were selected for this study. Different light intensities (670, 130, 300, and 600 mW/cm2, respectively) and different curing times (20s, 40s and 60s) were evaluated. Knoop microhardness test was performed in the area corresponding to the fractured region of the specimen. A total of 12 groups (n=10) were established and the specimens were prepared using a stainless steel mold composed by two similar parts that contained a cone-shaped hole with two diameters (8.0 mm and 5.0 mm) and thickness of 1.0 mm. Next, the specimens were loaded in tensile strength until fracture in a universal testing machine at a crosshead speed of 0.5 mm/min and a 50 kg load cell. For the microhardness test, the same matrix was used to fabricate the specimens (12 groups; n=5). Microhardness was determined on the surfaces that were not exposed to the light source, using a Shimadzu HMV-2 Microhardness Tester at a static load of 50 g for 30 seconds. Data were analyzed statistically by two-way ANOVA and Tukey's test (p<0.05). Regarding the individual performance of the light-curing units, there was similarity in tensile strength with 20-s and 40-s exposure times and higher tensile strength when a 60-s light-activation time was used. Regarding microhardness, the halogen lamp had higher results when compared to the LED units. For all light-curing units, the variation of light-exposure time did not affect composite microhardness. However, lower irradiances needed longer light-activation times to produce similar effect as that obtained with high-irradiance light-curing sources.
机译:这项研究的目的是评估不同光固化单元对复合树脂(Filtek Z250-3M / ESPE)的拉伸粘合强度和显微硬度的影响。本研究选择了常规卤素灯(Cing Light 2500-3M / ESPE; CL)和两个蓝色发光二极管固化装置(Ultraled-Dabi / Atlante; UL; Ultrablue IS-DMC; UB3和UB6)。评估了不同的光强度(分别为670、130、300和600 mW / cm2)和不同的固化时间(20s,40s和60s)。努氏显微硬度测试在与样品的断裂区域相对应的区域中进行。总共建立了12组(n = 10),并使用由两个相似的零件组成的不锈钢模具制备样品,该零件包含两个直径(8.0毫米和5.0毫米),厚度为1.0毫米的锥形孔。接下来,在万能试验机中以0.5 mm / min的十字头速度和50 kg称重传感器在拉伸试验中加载样品直至断裂。对于显微硬度测试,使用相同的基质制作样品(12组; n = 5)。使用Shimadzu HMV-2显微硬度测试仪在50 g的静态载荷下30秒,测定未暴露在光源下的表面的显微硬度。通过双向方差分析和Tukey检验对数据进行统计学分析(p <0.05)。关于光固化单元的个别性能,在20秒和40秒的曝光时间下拉伸强度相似,而在使用60秒的光活化时间时拉伸强度更高。关于显微硬度,与LED单元相比,卤素灯具有更高的结果。对于所有光固化单元,曝光时间的变化都不会影响复合材料的显微硬度。但是,较低的辐照度需要较长的光激活时间才能产生与使用高辐照度光固化源获得的效果相似的效果。

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