Effect of Co-Cr coating by EB-PVD on the bonding strength between titanium and porcelain.

To investigate the effect of the deposited Co-Cr coatings on the bonding strength of titanium-porcelain restoration, Co-Cr coatings with different thickness were deposited onto the pure titanium substrate by electron beam physical vapor deposition (EB-PVD).Sixty pure titanium specimens (25.0 mm×3.0 mm×0.5 mm) were randomly divided into 5 groups. Four Co-Cr coatings with different thickness, including 20, 40, 60 and 80 nm, were deposited onto the specimens (group A, B, C and D, respectively). Sandblasting treatment was selected as a control group (group E). After porcelain fusion, bonding strengths of titanium-porcelain restoration were measured by three-point bending test according to ISO 9 693. Scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) were employed to evaluate the morphology and elemental composition of both Co-Cr coatings and interfaces of the titanium-porcelain restoration.The bonding strengths in the group E and the test groups (groups A, B, C, and D) were (30.23±1.94), (36.11±1.17), (43.33±1.17), (39.95±2.22), (38.85±1.10) MPa, respectively. In contrast to the group E, the Co-Cr coatings significantly improved the bonding strength between titanium and porcelain (P<0.05). Moreover, some cracks and pores were found at the titanium-porcelain interface in the group E, while the titanium-porcelain interface in the group B was tight and compact (P<0.05). Meanwhile, comparing to the group E, more residual porcelains were found on the substrate of group B (P<0.05).Co-Cr coating with appreciate thickness using EB-PVD could significantly improve bonding strength between titanium and porcelain.目的: 应用电子束蒸镀的方法于纯钛表面沉积不同厚度钴铬合金涂层以研究其对钛瓷结合强度的影响。方法: 将60个喷砂后的钛片(25.0 mm×3.0 mm×0.5 mm)随机分成实验组(A，B，C，D组)和对照组(E组) 5组，实验组喷砂后通过电子束蒸镀的方式于表面形成不同厚度的钴铬合金涂层，其厚度分别为20 nm(A组)、40 nm(B组)、60 nm(C组)、80 nm(D组)，E组仅喷砂处理。对电子束蒸镀完成后于纯钛表面形成的涂层进行扫描电镜(scanning electron microscope，SEM)观察及能谱(energy dispersive spectrum，EDS)分析，试件烤瓷后通过三点弯曲力学试验检测其钛瓷结合强度，瓷剥脱后进行SEM和EDS分析以及钛瓷结合界面的SEM和线性分析。结果: A，B，C，D，E组钛瓷结合强度分别为(36.11±1.17)，(43.33±1.17)，(39.95±2.22)，(38.85±1.10)和(30.23±1.94) MPa。实验组钛瓷结合强度均高于对照组(均P<0.05)，且高于ISO 9693规定的临床标准，其中B组(40 nm)的钛瓷结合界面结合紧密，无空洞及裂隙，钛瓷结合强度和钛片瓷剥脱后表面瓷粉残留高于其他各组(均P<0.05)。结论: 通过电子束蒸镀的方式于纯钛表面形成适宜厚度的钴铬合金涂层可提高钛瓷结合强度。.