光固化成型ZTA全瓷冠的机械性能及精度研究

Mechanical Properties and Precision Analysis of Zirconia Toughened Alumina Crowns Fabricated by Stereolithography Method

目的:研究利用立体光固化成型(stereolithography,SLA)技术制作氧化锆增韧氧化铝(zirconia toughened alumina,ZTA)试件的机械性能及其全瓷冠的精度研究,为其临床应用提供实验依据。方法:将SLA技术制作的ZTA试件(SL组,stereolithography)与数控切削的氧化锆试件(CM组,CAD/CAM milling)进行抗弯强度(ISO 6872)、硬度、断裂韧性、脆性指数比较,并制作相应全瓷冠进行精度比较。结果:虽然SL组抗弯强度小于CM组(P>0.05),但已达(579.01±43.24)MPa,符合包含磨牙的三单位修复体基底陶瓷的最小挠曲强度临床标准;硬度及脆性指数大于CM组,断裂韧性小于CM组,差异均有统计学意义(P<0.05)。SL组全瓷冠的精度在外表面与CM组无明显差异(P>0.05),在内表面比CM组较差(P<0.05)。结论:利用SLA技术制作ZTA全瓷冠的机械性能及精度能初步满足临床要求,但与数控切削技术仍有一定差距,在后期临床应用推广前尚需优化。

Objective:To evaluate the mechanical properties and precision of zirconia toughened alumina(ZTA)crowns fabricated by stereolithography(SLA)method.Methods:ZTA specimens(group SL)were made by SLA technology and zirconia specimens(group CM)were made by CAD/CAM milling technology.The flexural strength,Vickers hardness,fracture toughness,and brittleness index were compared.Ten ZTA crowns were made by SLA technology and ten zirconia crowns were made by CAD/CAM milling technology.The precision was evaluated.Results:Although the flexural strength of group SL was lower than that of group CM(P>0.05),it satisfied the clinical requirement(579.01±43.24)MPa.The Vickers hardness and brittleness index of group SL were higher than group CM,and the fracture toughness of group SL was lower than group CM(P<0.05).There was no significant difference on the precision between two all-ceramic crown groups in the outer surface(P>0.05),however,significant difference in the inner surface(P<0.05).Conclusion:Although in the clinical acceptable range,the mechanical properties and precision of ZTA crowns made by SLA method are still less than those of crowns made by CAD/CAM milling technology.It needs further optimization.