Study of zirconia surface modification by femto-second laser.

采用飞秒激光技术对氧化锆牙修复体进行表面改性，以提高其粘接强度。在本研究中，在表面采用了两种直线微槽对齐方式。考察了粘接剪切强度的提高以及取向对强度的影响。利用飞秒激光系统对直径为5 mm的全烧结氧化锆棒的圆端面进行了激光加工，脉冲能量为9μJ，光斑进给量为5μm/脉冲。通过该工艺获得了深度为51μm、宽度为53μm的微槽。在这项研究中，在直线槽中产生了两种类型的对准。在第一种排列中，直线槽线是平行的。在第二种方案中，两组平行的凹槽相互垂直，将改性后的氧化锆表面粘接在Crearfi DC Core Auto-Mix One(Kuraray Medical Inc.，日本)的镜面上，将玻璃片的表面转移到镜面上。使用的粘结剂是Crearfi SA Cement Auto-Mix Universal(Kuraray Medical Inc.，日本)。厚度为50μm，圆形粘结区直径为4 mm。粘接剪切强度试验是在岛津公司的DCS5000万能试验机上进行的，十字头的速度为1 mm/min，有直线平行微槽的氧化锆表面的粘接剪切强度为35.8(S.D.：6.0)Mpa，而未开槽的原始表面的粘接剪切强度为23.4(S.D.：9.2 Mpa)。此外，具有交叉型微槽的表面强度提高到46.8(S.D.：5.5)Mpa。利用飞秒激光进行表面改性，在表面形成微沟槽，是提高氧化锆修复体与骨水泥粘接强度的有效手段。

We modified the surface of zirconia dental prostheses through femto-second laser process in order to improve the adhesion strength of them. In this study, two alignments of linear micro-grooves were employed on the surface. The increase of adhesion shear strength and the effect of the alignment on the strength were examined. A round end surface of a fully-sintered zirconia bar with diameter of 5mm was processed with femto-second laser system, which provided pulse energy of 9μJ and spot feed of5μm/pulse. Through the process, micro grooves with depth of 51μm and width of 53μm were obtained. In this study, two types of alignments in linear grooves were produced. In the first alignment, straight groove lines were parallel. In the second, two groups of parallel grooves were perpendicular to each other.The modified zirconia surfaces were bonded to the mirror surface of Crearfil DC Core Auto-mix ONE (Kuraray Medical Inc.,Japan) to which the surface of a glass slide was transferred. The adhesion used was Crearfil SA Cement Auto-mix universal (Kuraray Medical Inc.,Japan). The thickness was 50μm and the diameter of round bonded area was 4mm. Adhesion shear strength tests were carriedout on the universal testing machine(DCS-5000, Shimazu Co.), in which the speed of cross head was 1mm/min.The adhesion shear strength of zirconia surface with linear parallel microgrooves was35.8(S.D.:6.0) MPa, while the strength of original surface without grooves was23.4(S.D.:9.2) MPa. Moreover, the strength of the surface with cross-typed microgrooves increased up to 46.8(S.D.:5.5) MPa. The surface modification through femto-second laser process, in which micro-grooves were formed on it, is very useful tool for improving the adhesion strength between zirconia prostheses and cements.