使用FUS-invest锆系牙科纯钛包埋料提高铸件的物理机械性能及精度

目的:评价自制FUS-invest锆系牙科纯钛包埋料铸造的纯钛铸件的物理机械性能及标准化单冠的精度.方法:制备7个厚度为0.8 mm的纯钛比例铸件.经伺服液压动态实验系统、断口扫描电镜观察及能谱分析,评价其物理机械性能.制备38个标准化单冠,实验组(FUS-invest锆系包埋料)、对照组(磷酸盐系包埋料)各19个,测量显微镜测标准化单冠边缘差异值d和铸件内壁与工作模的距离,进行铸件精度评价.采用SPSS17.0软件包对数据进行统计学分析.结果:①纯钛铸件的弹性模量为(123.5±14.2)GPa,屈服强度为(569.3±16.5) MPa,抗拉强度为(668.4±16.1) MPa,延伸率为(4.5±0.2)％;断口EDS分析除钛元素外,不同深度处可发现少量不同含量的Si元素和Fe元素,但未检测出Zr元素.②精度实验中,单因素方差分析及两独立样本t检验显示,组内标准化单冠边缘4个标记点处的测量值无显著差异(P＞0.05);实验组和对照组相比亦无显著差异(P＞0.05).2组内部测量值无显著差异(P＞0.05),而组内内部不同标记点间差异显著(P＜0.01).结论:虽然FUS-invest锆系包埋料铸造获得铸件的延伸率略低,但各项物理机械性能均达到临床要求.无论边缘适合性还是内部适合性,2组均无显著差异且均在临床可接受范围,2组边缘差异均值约为46 μm,内部近咬合面的差异均值约为56 μm,内部轴壁处的差异均值约为0.

Research on physical and mechanical properties,crown accuracy by using self-made FUS-invest dental investment

PURPOSE:To evaluate the physical and mechanical properties of pure titanium castings cast by self-made FUS-invest dental investment,and evaluate casting accuracy.METHODS:Seven pure titanium castings were cast by selfmade FUS-invest zirconium investment and analyzed using servo hydraulic dynamic experiment system (JJG139-83 standard),scanning electron microscope and energy spectrum analysis.Thirty-eight crowns of pure titanium were cast by two different methods.One cast by FUS-invest zirconium embedding material was used for experiment and the other cast by phosphate embedding material was used as control.Casting accuracy was assessed through measuring the difference value d at the marginal marker points and distance between casting pieces of wall and working modes of casting were examined under microscope.Scanning electron microscope with energy-dispersive spectrum (EDS) was used to analyze the status of composition of the casting surface.SPSS 17.0 software package was used to investigate the difference of two groups.RESULTS:①Qualitative analysis of servo hydraulic dynamic experiment system showed various mechanical properties:elastic modulus (123.5±14.2) GPa,yield strength (569.3±16.5) MPa,tensile strength (668.4±16.1) MPa,elongation (4.5±0.2)％.EDS analysis of the fracture was observed at different depth (13,25,50,350 μm) under the surface of pollution layer,a little Si and Fe with different atomic percentage was found but no Zr.②No significant difference (P＞0.05) was found between each group of four markers on the marginal fit,and internal fit,whereas significant difference (P＜ 0.01) was found at different marker point.CONCLUSIONS:The mechanical properties of commercially pure titanium casting by self-made FUS-invest zirconium-based investment can meet the qualification of dental metal materials,although elongation was a little lower.Both the marginal adaptation and internal fit between the two groups had no significant difference.The mean marginal difference was 46 μm,the mean internal difference at axial angle was 56 μm and approximately 0 at axial wall.