七种光固化复合树脂冷热循环后机械性能评价(英文)

目的研究7种不同的光复合树脂热循环试验后的机械性能,探讨各性能之间的关系。方法将每种树脂(A110:AH、ESTELITE∑:ET、AELITE:AT、Z250:ZS、CharmFil plus:CP、Z350:ZH、Grandio:GD,其中AH、ET为微充填复合树脂,AT、ZS、CP为混合型复合树脂,ZH、GD为纳米型复合树脂)制成直径为12 mm,厚度为1.0 mm的实验样本。所得样本在37℃的蒸馏水中浸泡24 h,然后在5℃和55℃下间隔15 s冷热循环1 000次。应用尖端速率为0.5 mm/min的双轴挠曲强度试验测量材料的强度值(ISO4049),所得数据采用Weibull和ANOVA统计学分析。样本断面经扫描电镜观察,剩余样本碎片经Knoop硬度试验测试(负载50 g,时间10 s)。结果最高和最低的Weibull系数值分别出现在AH(18.752)和AT(5.290)组,最高和最低的双轴挠曲强度值分别出现在ZS(158.2MPa)和ET(54.0 MPa)组。不同填料的强度值大小依次为混合型复合树脂>纳米型复合树脂>微充填复合树脂,具有相同类型填料的复合树脂之间的强度值差异没有统计学意义(P>0.05),且强度试验所得碎片的数量与材料强度大小成正相关。GD组的硬度值最大(110.81±14.77)kg/mm2,AH组平均硬度值最小(42.81±1.91)kg/mm2,复合树脂的强度值与硬度值成正相关。扫描电镜观察显示树脂基质和填料之间是裂痕形成的薄弱部位。结论纳米型复合树脂比混合型复合树脂更适于临床应用。Knoop硬度实验是否适用于复合树脂材料的硬度测量还需要进一步证实。

Changes in mechanical properties of seven light-cured composite resins after thermal cycling

Objective To examine the changes of the mechanical properties of 7 different light-cured composite resins after thermal cycling and the correlations between these properties.Methods Seven different light-cured composite resins,including 2 microfilled composites (A110:AH and ESTELITE ∑:ET),3 microhybrid composites (AELITE:AT,Z250:ZS,and CharmFil plus:CP),and 2 nanohybrid composites (Z350:ZH and Grandio:GD),were prepared into test specimens with a diameter of 12 mm and a thickness of 1.0 mm.The specimens were stored in distilled water at 37 ℃ for 24 h prior to 1 000thermal cycles of 5 ℃ for 15 s and 55 ℃ for 15 s.The biaxial flexural strength (of) was tested using the ball-on-three-ball method at a crosshead speed of 0.5 mm/min (ISO4049).The fracture surface was observed under scanning electron microscope (SEM),and the remaining specimens underwent Knoop hardness test with a 50-g loading for 10 s.Results The highest and lowest Weibull modulus was observed in AH (18.752) and AT (5.290) group,respectively.The highest and lowest biaxial flexural strength was observed in ZS (158.2 MPa) and ET (54.0 MPa) groups,respectively.The off of the tested materials decreased in the order of microhybrid composite,nanohybrid composite,and microfiller composite,and the of showed no significant difference between the composites with a similar filler (P＞0.05).The fracture number was positively correlated tothe strength of the material.The Knoop hardness numbers (H) was the highest in GD group (110.81+ 14.77 kg/mm2) and the lowest in AH group (42.81+ 1.91 kg/mm2).SEM showed that the interface region of the matrix and the filler was vulnerable to crack formation.Conclusion The nanohybrid composite resins better suit clinical applications than microhybrid composites.The applicability of Knoop hardness test in hardness measurement of the composite resins needs to be further demonstrated.