Murray Andrea K, Attrill David C, Dickinson Mark R
Laser Photonics Group, Department of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL, UK.
Dent Mater. 2005 Sep;21(9):837-45. doi: 10.1016/j.dental.2005.01.003.
The aims of this study were to compare the mode of debonding (adhesive or cohesive) of laser-etched Ni-Cr alloy (Wiron 99) to a standard sandblasting technique, and to a combination of sandblasting and laser etching. The etched surfaces were examined using optical and electron microscopy techniques.
Five groups of randomly allocated Ni-Cr cylinders were prepared: Group I-sandblasted; Groups II-IV-laser etched at three fluences (3.0, 4.0 and 4.9 J/cm2), Group V-combination sandblasting and laser etching (4.0 J/cm2). Within groups specimens were bonded into pairs (N=8) with composite luting cement (Panavia 21) prior to tensile debonding. Optical and scanning electron microscopy were performed both prior to and following debonding.
An oxide layer was observed on sample surfaces before surface preparation by lasing or abrasion. Sandblasting removed the oxidation layer, which low and medium laser fluences alone failed to fully ablate. The highest (4.9 J/cm2) laser fluence melted the surface of the Ni-Cr alloy, covering the oxidation layer. A combination of sandblasting and lasing at 4.0 J/cm2 allowed full removal of the surface oxidation layer due to abrasion, followed by roughening of the surface with the laser. This resulted in greater mean tensile debonding strengths [Murray, A, Attrill, D, Dickinson, M. Dent Mater, 2004, In press] and a tendency for cohesive rather than adhesive interface failures. Groups I-IV underwent partial adhesive failure at both surfaces. Group V, in the main, underwent cohesive failure with a layer of adhesive remaining on both surfaces.
Laser etching of Ni-Cr alloy in combination with sandblasting optimises bonding to composite luting agents, resulting in a high proportion of cohesive failures when compared to sandblasting or lasing alone.
本研究旨在比较激光蚀刻镍铬合金（Wiron 99）与标准喷砂技术以及喷砂和激光蚀刻相结合的脱粘模式（粘结性或内聚性）。使用光学和电子显微镜技术对蚀刻表面进行检查。
制备五组随机分配的镍铬圆柱体：第一组 - 喷砂处理；第二至四组 - 以三种能量密度（3.0、4.0和4.9 J/cm²）进行激光蚀刻，第五组 - 喷砂和激光蚀刻相结合（4.0 J/cm²）。在每组中，在拉伸脱粘之前，将标本用复合粘结剂（Panavia 21）成对粘结（N = 8）。在脱粘之前和之后都进行了光学和扫描电子显微镜检查。
在通过激光或研磨进行表面处理之前，在样品表面观察到氧化层。喷砂去除了氧化层，而单独的低和中等激光能量密度未能完全去除该氧化层。最高（4.9 J/cm²）的激光能量密度使镍铬合金表面熔化，覆盖了氧化层。4.0 J/cm²的喷砂和激光蚀刻相结合，由于研磨作用完全去除了表面氧化层，随后激光使表面粗糙化。这导致了更高的平均拉伸脱粘强度[默里，A，阿特里尔，D，迪金森，M。牙科材料，2004，即将发表]，并且倾向于内聚性而非粘结性界面失效。第一至四组在两个表面均发生部分粘结性失效。第五组主要发生内聚性失效，两个表面均残留一层粘结剂。
镍铬合金的激光蚀刻与喷砂相结合可优化与复合粘结剂的粘结，与单独的喷砂或激光蚀刻相比，内聚性失效的比例更高。
