Sharafeddin Farahnaz, Motamedi Mehran, Fattah Zahra
Biomaterial Research Center, Dept. of Operative Dentistry, School of Dentistry, Shiraz University of Medical Science, Shiraz, Iran.
Dept. of Operative Dentistry, School of Dentistry, Shiraz University of Medical Science, Shiraz, Iran.
J Dent (Shiraz). 2015 Sep;16(3 Suppl):224-9.
Composite resin may be used in different temperatures; it is crucial to determine the effect of temperature on mechanical properties of nanohybrid and silorane-based composite.
This in vitro study compared the flexural strength and modulus of elasticity of nanohybrid and silorane-based resin composite, at 4˚C, room temperature (25˚C), and 45˚C.
In this experimental study, 60 specimens were prepared in a metal split mold (2×2×25mm). Two different resin composites, Filtek Z250 XT (3M/ ESPE) and Filtek P90 (3M/ESPE), were evaluated. The material were inserted into split molds at room temperature, 4˚C or 45˚C and cured with LED (1200 mW/cm(2)) for 20 seconds in four points (n=10). Then, a three-point bending test was performed using a universal testing machine at a crosshead speed of 0.5 mm/min for measuring the flexural strength and flexural modulus of samples. The data were analyzed by the two-way ANOVA and Tukey test (p< 0.05).
The mean highest flexural strength was observed at 45˚C, showing statistically significant difference with flexural strength at 4˚C (p= 0.0001) and 25˚C (p= 0.003) regardless of the type of resin composite. The flexural modulus at 45˚C was highest, showing the statistically significant difference with flexural modulus at 4˚C (p= 0.0001) and 25˚C (p= 0.002). The flexural modulus was statistically different between nanohybrid and silorane-based resin composite (p= 0.01) in 25˚C and 45˚C, but there were no statistically significant differences between flexural strength of Filtek Z250 XT and Filtek P90 regardless of the temperatures (p= 0.062).
Preheating the resin composite at 45˚C improves flexural strength and modulus of nanohybrid and silorane-based resin composite. However, flexural strength and modulus of the tested materials were not affected by precooling. The flexural modulus of nanohybrid resin composite was significantly higher than silorane-based resin composite in 25˚C and 45˚C temperatures.
复合树脂可在不同温度下使用；确定温度对纳米混合和硅氧烷基复合树脂力学性能的影响至关重要。
本体外研究比较了纳米混合和硅氧烷基树脂复合材料在4˚C、室温（25˚C）和45˚C下的弯曲强度和弹性模量。
在本实验研究中，使用金属分体模具（2×2×25mm）制备60个样本。评估了两种不同的树脂复合材料，Filtek Z250 XT（3M/ ESPE）和Filtek P90（3M/ESPE）。将材料在室温、4˚C或45˚C下插入分体模具中，并用LED（1200 mW/cm(2)）在四个点固化20秒（n = 10）。然后，使用万能试验机以0.5 mm/min的十字头速度进行三点弯曲试验，以测量样本的弯曲强度和弯曲模量。数据通过双向方差分析和Tukey检验进行分析（p < 0.05）。
无论树脂复合材料的类型如何，在45˚C时观察到的平均弯曲强度最高，与4˚C（p = 0.0001）和25˚C（p = 0.003）时的弯曲强度相比具有统计学显著差异。45˚C时的弯曲模量最高，与4˚C（p = 0.0001）和25˚C（p = 0.002）时的弯曲模量相比具有统计学显著差异。在25˚C和45˚C时，纳米混合和硅氧烷基树脂复合材料之间的弯曲模量存在统计学差异（p = 0.01），但无论温度如何，Filtek Z250 XT和Filtek P90的弯曲强度之间均无统计学显著差异（p = 0.062）。
将树脂复合材料在45˚C下预热可提高纳米混合和硅氧烷基树脂复合材料的弯曲强度和模量。然而，测试材料的弯曲强度和模量不受预冷的影响。在25˚C和45˚C温度下，纳米混合树脂复合材料的弯曲模量显著高于硅氧烷基树脂复合材料。
