钛表面镀铬对纯钛烤瓷剪切强度的影响

Effect of pure titanium electroplated chromium on shear bond strength between porcelain and titanium

目的评估钛表面镀铬对纯钛烤瓷剪切强度的影响。方法 70个纯钛标准试件(10 mm×10 mm×1 mm)分为3组,A组10个(不进行任何处理);B组30个,5%硝酸铬溶液(w/v)处理;C组30个,10%硝酸铬溶液(w/v)处理;B组和C组根据电镀时间不同(0.5、1、2 h)又分为3个亚组,每一组中5个试件用Vita Titankeramik瓷粉,5个试件用Triceram瓷粉。钛瓷界面万能试验机(0.5 mm/min)进行剪切测试,并对断裂界面进行电镜扫描,用方差分析法和Tukey检验法分析。结果钛表面镀铬后与瓷粉的结合强度明显提升,差异有统计学意义(P<0.05),瓷粉对结合强度的影响无统计学意义,其中0.5 h、10%硝酸铬溶液、Vita Titankeramik瓷粉,0.5 h、5%硝酸铬溶液、Triceram瓷粉的结合强度是两个实验组中最高的,分别达到了(26.72±5.78)MPa和(25.48±4.14)MPa,0.5 h、10%硝酸铬溶液、钛-Vita T组和0.5 h、5%硝酸铬溶液、钛-Triceram组可以很好地提高钛-瓷结合强度,电镜扫描图也显示镀铬可以提高钛-瓷的结合强度。结论 0.5 h、5%硝酸铬溶液对于提高结合强度已经足够。说明铬层可以很好地阻挡钛-氧结合,减少钛氧层厚度,有效提高钛-瓷结合强度。

Objective To evaluate the effect of pure titanium electroplated chromium on the shear bond strength between titanium and porcelain. Methods Seventy specimens of machined commercially pure titanium （CP Ti） plates grade Ⅱ （10 mm × 10 mm× 1 mm） were prepared. The specimens were divided into three groups saccording to the concentration of eleetroplating solution, Gr Ⅰ （ control without electroplating, n = 10）, Gr Ⅱ （5%, w/v, of chromium nitrate solution, n = 30） and Gr Ⅲ （ 10%, w/v, of chromium nitrate solution, n =30）. Groups Ⅱ and m were further divided into three subgroups （n = 10） according to the electroplating time （0.5, 1 and 2 h）. Two titanium-porcelains （Vita Titankeramik and Triceram） were applied to each subgroup （n = 5）. The titanium-porcelain interfaces were loaded under shear in a universal testing machine （crosshead speed： 0.5 mm/min） until failure occurred. Failure types were examined by stereomicroscopy and the titanium-porcelain interface examined by SEM. Data were analyzed using ANOVA and Tukey＇ s test. Results Bond strength values were significantly affected by the type of electroplating treatment （P 〈 0.05 ）, but not by the type of porcelain. The CP Ti/Vita Titankeramik （0.5 h,10% , w/v） and the CP Ti/Trieeram （0.5 h 5% , w/v） groups showed the highest bond strength（MPa） （26.72 ± 5.78 and 25.48 ± 4. 14 ） respectively among the groups, suggesting that surface treatment of CP Ti using chromium interlayer coating for 0.5 h 5% （w/v） and 0.5 h 10% （w/v） by electroplating enhanced the shear bond strength between titanium and porcelain. Stereomicroscope and SEM images showed that chromium interlayer enhanced the bond strength between porcelain and titanium. Conclusions There are no significant differences between chromium plating treatment for 0. 5 h 5% （w/v） and 0. 5 h 10% （w/v） in the bond strength for both types of titanium-porcelain. Consequently, eleetroplating treatment using 5% （w/v） for 0. 5 h may he sufficient for bond improvement between titanium and porcelain. It appears that the Cr interlayer acts as a good oxygen diffusion barrier and effectively prevents excessive oxidation of titanium surfaces at porcelain sintering temperatures.