Li R, Ren Y, Han J
Department of Stomatology, 3rd Affiliated Hospital, Sun Yat-San Medical University.
Hua Xi Kou Qiang Yi Xue Za Zhi. 2000 Dec;18(6):377-9.
To evaluate the shear bond strength of composite resin bonded to pretreated porcelain surfaces by use of a pulsed Nd:YAG laser irradiation and by use of 8% hydrofluoric etching.
Surfaces of porcelain were roughened with coarse diamonds until the opaque body porcelains were exposed. The samples were divided into four groups. Samples of the first group were etched with 8% hydrofluoric acid for 3 min by following the manufacter's instructions. Samples of the 2nd, 3rd and 4th groups were separately irradiated by a pulsed Nd:YAG laser of three energy parameters of 15 Hz, 40 mJ; 0.6 W; 15 Hz, 60 mJ, 0.9 W and 15 Hz, 80 mJ, 1.2 W different respectively, each specimen was irradiated for 1 min. Then, silane coupling agent was equally placed on the treated surfaces for 3 min, the activator was used on each surface. The adhesive was applied and light-cured. The composite resin material was finally bonded to the treated porcelain surface, forming a 3 mm x 3 mm x 2 mm resin mass. Samples were then tested for shear bond strength between the treated porcelain and composite resin by using a SWD-10 electric universal testing machine with a crosshead speed of 1 mm/min until fracture. At the end of testing, the data was evaluated by using a two-way analysis of variance (ANOVA) comparing the shear bond strength. On the other hand, characteristic morphology of laser irradiated surfaces of porcelain was prepared and observed by a scanning electron microscopy.
The shear bond strength of laser groups of 0.6 W, 0.9 W, 1.2 W and etching group was respectively 8.61, 14.07, 11.22 and 13.47 MPa. There was no significantly difference among groups of laser 0.9 W, 1.2 W and the etching group. This suggested that irradiated on surfaces of porcelain by Nd:YAG laser at the above laser energy could attain the same effectiveness as hydrofluoric acid etching. But the shear bond strength of laser 0.6 W group was significantly lower than the etching group. It suggested that shear bond strength would obviously decrease when laser energy was 0.6 W or lower than this parameter, and had no use in treatment on porcelain surfaces comparing to acid etching. SEM showed that porcelain surfaces irradiated by Nd:YAG laser exhibited rough, umbilicate, lava crater-like structure. This structure helped to produce mechanical retention between resin composite and porcelain.
The pulsed Nd:YAG laser could replace etching method to pretreat the fracture porcelain surfaces for bonding with composite resin at appropriate energy parameters.
评估通过脉冲Nd:YAG激光照射和8%氢氟酸蚀刻预处理后的瓷表面上复合树脂的剪切粘结强度。
用粗金刚石将瓷表面粗糙化，直至暴露不透明体瓷。将样品分为四组。第一组样品按照制造商说明用8%氢氟酸蚀刻3分钟。第二、三、四组样品分别用三种不同能量参数的脉冲Nd:YAG激光照射，参数分别为15Hz、40mJ、0.6W；15Hz、60mJ、0.9W；15Hz、8mJ、1.2W，每个样品照射1分钟。然后，将硅烷偶联剂均匀涂覆在处理过的表面上3分钟，在每个表面上使用活化剂。施加粘合剂并光固化。最后将复合树脂材料粘结到处理过的瓷表面上，形成一个3mm×3mm×2mm的树脂块。然后使用SWD - 10电动万能试验机以横梁速度1mm/min测试处理过的瓷与复合树脂之间的剪切粘结强度，直至断裂。测试结束时，使用双向方差分析（ANOVA）评估数据，比较剪切粘结强度。另一方面，制备并通过扫描电子显微镜观察瓷的激光照射表面的特征形态。
0.6W、0.9W、1.2W激光组和蚀刻组的剪切粘结强度分别为8.61、14.07、11.22和13.47MPa。0.9W、1.2W激光组和蚀刻组之间无显著差异。这表明在上述激光能量下用Nd:YAG激光照射瓷表面可达到与氢氟酸蚀刻相同的效果。但0.6W激光组的剪切粘结强度明显低于蚀刻组。这表明当激光能量为0.6W或低于此参数时，剪切粘结强度会明显降低，并与酸蚀刻相比在瓷表面处理中无用。扫描电子显微镜显示，Nd:YAG激光照射的瓷表面呈现粗糙、脐状、火山口状结构。这种结构有助于在树脂复合材料和瓷之间产生机械固位。
在适当的能量参数下，脉冲Nd:YAG激光可替代蚀刻方法预处理断裂的瓷表面以与复合树脂粘结。
