Piva Evandro, Correr-Sobrinho Lourenço, Sinhoreti Mario Alexandre Coelho, Consani Simonides, Demarco Flávio Fernando, Powers John Michael
Department of Restorative Dentistry, Dental School, Federal University of Pelotas, Pelotas, RS, Brazil.
J Appl Oral Sci. 2008 May-Jun;16(3):189-93. doi: 10.1590/s1678-77572008000300005.
The purpose of this study was to evaluate the Knoop hardness of a dual-cured resin-based luting cement irradiated with different light sources as well energy density through a ceramic sample. Three light-curing unit (LCUs) were tested: tungsten halogen light (HAL), light-emitting diode (LED) and xenon plasma-arc (PAC) lamp. Disc-shaped specimens were fabricated from a resin-based cement (Enforce). Three energy doses were used by modifying the irradiance (I) of each LCU and the irradiation time (T): 24 Jcm(-2) (I/2x2T), 24 Jcm(-2) (IxT) and 48 Jcm(-2) (Ix2T). Energy doses were applied through a 2.0-mm-thick ceramic sample (Duceram Plus). Three groups underwent direct irradiation over the resin cement with the different LCUs and a chemically-activated group served as a control. Thirteen groups were tested (n=10). Knoop hardness number (KHN) means were obtained from cross-sectional areas. Two-way ANOVA and the Holm-Sidak method were used for statistical comparisons of activation mode and energy doses (alpha=5%). Application of 48 J.cm(-2) energy dose through the ceramic using LED (50.5+/-2.8) and HAL (50.9+/-3.7) produced significantly higher KHN means (p<0.05) than the control (44.7+/-3.8). LED showed statistically similar performance to HAL. Only HAL showed a relationship between the increase of LCU energy dose and hardness increase.
本研究的目的是评估通过陶瓷样本，用不同光源以及能量密度照射的双固化树脂类粘结水门汀的努氏硬度。测试了三种光固化单元（LCU）：卤钨灯（HAL）、发光二极管（LED）和氙等离子弧（PAC）灯。由一种树脂类水门汀（Enforce）制作圆盘状样本。通过改变每个LCU的辐照度（I）和照射时间（T）使用三种能量剂量：24 J/cm²（I/2×2T）、24 J/cm²（I×T）和48 J/cm²（I×2T）。能量剂量通过一个2.0毫米厚的陶瓷样本（Duceram Plus）施加。三组使用不同的LCU对树脂水门汀进行直接照射，一组化学活化组作为对照。测试了13组（n = 10）。从横截面积获得努氏硬度值（KHN）均值。采用双向方差分析和霍尔姆 - 西达克方法对活化模式和能量剂量进行统计学比较（α = 5%）。使用LED（50.5±2.8）和HAL（50.9±3.7）通过陶瓷施加48 J/cm²能量剂量产生的KHN均值显著高于对照组（44.7±3.8）（p<0.05）。LED表现出与HAL在统计学上相似的性能。只有HAL显示出LCU能量剂量增加与硬度增加之间的关系。
