不同排溢沟设计对CEREC 3D全瓷冠边缘适合性和抗压强度影响的研究

The effect of different rows of overflow groove on the marginal accuracy and on the fracture strength of the CEREC 3D all-ceramic crown

目的探讨牙体预备中排溢沟设计对CEREC 3D全瓷冠边缘适合性和抗压强度的影响。方法制作三组不同排溢沟(无排溢沟、两排溢沟、四排溢沟)的复合树脂代型,黏固CEREC 3D全瓷冠。采用体视显微镜测量冠的边缘适合性。使用万用测力机测试其抗压强度。结果对照组与两排溢沟组及对照组与四排溢沟组之间边缘适合性和抗压强度存在显著差异;而两排溢沟组与四排溢沟组之间无显著差异。结论增加两条排溢沟可使CEREC 3D全瓷冠达到较好的的边缘适合性和抗压强度。

Objective To evaluate the effect of different rows of overflow groove on the marginal accuracy and on the fracture strength of the CEREC 3D all-ceramic crown.Methods Three types of composite resin die with different rows of overflow groove(no overflow groove,two rows of overflow groove,four rows of overflow groove)were made.Ten dies were made for each group of tooth preparation.Then CEREC 3D all-ceramic crowns were fabricated.The marginal adaption were measured with a stereomicroscope after cementation.Then the specimens were compressively loaded to failure in a universal testing machine.Results Marginal gaps and fracture strength between the group of no overflow groove and group of two rows of overflow groove,and between the group of no overflow groove and group of four rows of overflow groove,showed a significant difference,while there wasn't significant difference between the group of two rows and the group of four rows.Conclusion Increasing the rows of overflow groove decreased the marginal discrepancy of CEREC 3D all-ceramic crowns,thus improved the marginal fit and fracture strength,but this improvement became less evident when the rows of overflow groove was raised from two to four.