不同边缘设计对选择性激光熔覆钴铬合金基底冠边缘微渗漏的影响

Comparative study of microleakage by using different finished lines in selective laser melting metal crowns

目的 :研究不同边缘设计对选择性激光熔覆(selective laser melting,SLM)钴铬合金基底冠边缘微渗漏的影响。方法:选择30个离体磨牙,随机分为3组,每组10颗。A组设计135°浅凹状肩台并常规制作钴铬合金基底冠;B组和C组分别设计90°直角和135°浅凹状肩台并制作SLM钴铬合金基底冠,3组用玻璃离子粘固后,进行5000次冷热循环采用染料渗入法,用体式显微镜观察边缘微渗漏。采用SPSS 20.0软件包对数据进行统计学分析。结果:A组和B组,A组和C组间边缘微渗漏差异均有显著性(P<0.05),B组的微渗漏大于C组,但两者之间的差异无显著性(P>0.05)。结论 :2种边缘设计的SLM钴铬合金基底冠微渗漏均显著小于传统铸造钴铬合金基底冠;从减少边缘微渗漏和保护牙体组织的角度出发,在进行SLM基底冠修复时,建议使用浅凹型肩台。

PURPOSE： To evaluate microleakage of SLM Co -Cr alloy metal crown with two types finished line （chamfer and shoulder）, compared with conventional fabrication of Co -Cr alloy metal crowns. METHODS： Thirty healthy non- carious human molars were selected and randomly assigned to 3 groups, 10 in each. Teeth in group A and C received a chamfer finish line preparation, whereas teeth in group C received a shoulder finish line. Conventional Co -Cr alloy metal crowns were fabricated for group A when SLM metal crowns were made for group B and group C. Glass ionomer was applied for bonding. After 5000 thermocycles ranging from 5℃ to 55℃,all the specimens were evaluated by dye penetration and then microleakage was examined under light microscope. The data were analyzed statistically with SPSS 20.0 software package. RESULTS： Microleakage in group A was significantly higher than the other two groups, group B and group C showed no significant difference in microleakage while microleakage in group B was higher than that in group C. CONCLUSIONS： Microleakage of SLM metal crowns was significantly less than that of conventional Co-Cr alloy metal crowns; chamfer finish line designs was recommended for SLM metal crowns in consideration of reducing microleakage and protecting tooth.