Guiraldo Ricardo Danil, Consani Simonides, Consani Rafael Leonardo Xediek, Berger Sandrine Bittencourt, Mendes Wilson Batista, Sinhoreti Mario Alexandre Coelho
Prosthodontics Post-graduate Program, College Pythagoras, Belo Horizonte, MG, Brazil.
Bull Tokyo Dent Coll. 2009;50(4):183-90. doi: 10.2209/tdcpublication.50.183.
This study investigated the influence of different composite resin shades on light energy transmission through the composite, hardness and cross-link density (CLD). The composite Filtek Z250 was used in shades A1, A2, A3, A3.5 and A4. A quartz tungsten halogen light curing unit was used at an irradiance of 900 mW/cm(2). Thirty specimens were made for each shade. Light energy transmission that passed through the composite was calculated (n=10). Differences in Knoop hardness between the top and bottom (DKH) of the same specimen were calculated (n=10). The Knoop hardness value for each surface was recorded as the average of three indentations (KHN(1)). Thereafter, the specimens were soaked in absolute ethanol for 24hr at room temperature, and hardness was again determined (KHN(2)). The CLD was estimated by the softening effect produced by ethanol, i.e., by decrease in hardness. The percentage of decrease in KHN(2) compared with KHN(1) (PD) in the same specimen was then calculated for both surfaces (n=10). The data were submitted to an ANOVA in different tests (Light energy transmission, Knoop hardness and CLD). The irradiance of light that passed through composite shade A1 (408 mW/cm(2)) was statistically greater than that through shade A2 (376 mW/cm(2)), and was greater through A2 than A3 (359 mW/cm(2)) and through A3 than A3.5 (327 mW/cm(2)); A3.5 showed no statistical difference when compared to A4 (324 mW/cm(2)). The DKH of A4 (20.56%) was not statistically higher than that of A3.5 (20.14%), which was greater than that of A3 (14.08%), A2 (11.65%) and A1 (9.06%). There was no statistical difference in CLD. Darker shades had a significant influence on light energy transmission through dental resin composite and its hardness. However, CLD was not affected by darker dental composite shades.
本研究调查了不同复合树脂色阶对光透过复合树脂的能量传递、硬度和交联密度（CLD）的影响。使用了Filtek Z250复合树脂的A1、A2、A3、A3.5和A4色阶。采用石英钨卤素光固化机，辐照度为900 mW/cm²。每个色阶制作30个样本。计算透过复合树脂的光能量传递（n = 10）。计算同一样本顶部和底部努氏硬度的差异（DKH）（n = 10）。每个表面的努氏硬度值记录为三次压痕的平均值（KHN(1)）。此后，将样本在室温下于无水乙醇中浸泡24小时，再次测定硬度（KHN(2)）。通过乙醇产生的软化效应，即硬度降低来估计CLD。然后计算同一样本两个表面的KHN(2)与KHN(1)相比的硬度降低百分比（PD）（n = 10）。将数据在不同测试（光能量传递、努氏硬度和CLD）中进行方差分析。透过复合树脂色阶A1的光辐照度（408 mW/cm²）在统计学上高于透过色阶A2的（37 mW/cm²），透过A2的高于透过A3的（359 mW/cm²），透过A3的高于透过A3.5的（327 mW/cm²）；A3.5与A4（324 mW/cm²）相比无统计学差异。A4的DKH（20.56%）在统计学上不高于A3.5的（20.14%），A3.5的大于A3的（14.08%）、A2的（11.65%）和A1的（9.06%）。CLD无统计学差异。较深色阶对光透过牙科复合树脂的能量传递及其硬度有显著影响。然而，较深色的牙科复合树脂色阶对CLD没有影响。
