Taher Nadia Malek A
Division of Operative Dentistry, Department of Restorative Dental Sciences, College of Dentistry, King Saud University, P.O. Box 5967, Riyadh 11432, Saudi Arabia.
Saudi Dent J. 2010 Jul;22(3):107-12. doi: 10.1016/j.sdentj.2010.04.002. Epub 2010 Apr 18.
This study aimed to assess the bi-axial flexural strength of two dual-polymerizing resin luting agents cemented to human dentin when photo-activated with different light-curing units.
Two dual-cured resin cements: choice (CH) and Variolink II (VL) were tested. Hybrid composite resin (Z-250) discs (12 × 1.5 mm) were fabricated. Three types of light-curing units were used halogen-curing unit (QTH), light-emitting diode (LED) and plasma arc (PAC). Sixty dentin discs of 0.5 mm thickness were prepared from extracted human teeth. A circular mold (2.5 mm in height and 12 mm diameter) was utilized to create supporting structure for dentin, resin cement complex. The resin luting cement (0.5 mm) was placed on the previously prepared dentin discs and covered with the prefabricated composite discs. Photo-activation of cements was performed for 40 s with QTH and LED units and for 3 s with PAC. The specimens were divided into 12 groups (20 specimens for each light source). Six groups were kept in distilled water for 24 h and the rest were stored for 6 weeks. Bi-axial flexural strength was determined using Instron machine. The data was analyzed using two-way ANOVA and Tukey test for comparison.
The findings indicated that the bi-axial flexural strength values for both cements CH and VL were higher for 24 h over 6 weeks but not statistically significant when cured with QTH. Meanwhile, when LED light was used for photo-activation the cements, the flexural strength values reported were statistically higher of 24 h over 6 weeks storage at P = 0.4(E-6) However, PAC light did not record any statistically significant difference between two duration for the CH cement although when used for polymerization of VL the reported value for 6 weeks were statistically significantly higher value than 24 h duration at P = 0.002.
When high immediate flexural strength is preferred in clinical situation photo-activation the cements with LED reported the greatest value.
本研究旨在评估两种双重固化树脂粘结剂粘结至人牙本质时，使用不同光固化设备进行光激活后的双轴弯曲强度。
测试了两种双重固化树脂水门汀：Choice（CH）和Variolink II（VL）。制作了混合复合树脂（Z-250）圆盘（12×1.5毫米）。使用了三种类型的光固化设备：卤素固化设备（QTH）、发光二极管（LED）和等离子弧（PAC）。从拔除的人牙制备了60个厚度为0.5毫米的牙本质圆盘。使用一个圆形模具（高2.5毫米，直径12毫米）为牙本质、树脂水门汀复合体创建支撑结构。将树脂粘结水门汀（0.5毫米）放置在先前制备的牙本质圆盘上，并用预制的复合圆盘覆盖。使用QTH和LED设备对水门汀进行40秒的光激活，使用PAC进行3秒的光激活。将标本分为12组（每种光源20个标本）。6组在蒸馏水中保存24小时，其余组保存6周。使用Instron机器测定双轴弯曲强度。使用双向方差分析和Tukey检验进行数据分析以进行比较。
研究结果表明，CH和VL两种水门汀在QTH固化时，24小时的双轴弯曲强度值高于6周，但无统计学意义。同时，当使用LED光对水门汀进行光激活时，报告的弯曲强度值在24小时储存时比6周时在统计学上更高（P = 0.4(E-6)）。然而，PAC光对CH水门汀在两个时间段之间未记录到任何统计学上的显著差异，尽管在用于VL聚合时，报告的6周值在统计学上显著高于24小时时间段，P = 0.002。
在临床情况下，当首选高即时弯曲强度时，使用LED对水门汀进行光激活可获得最大的值。
