不同粘结剂和不同边缘设计对冠边缘微渗漏的影响

目的：研究不同粘结剂和不同边缘设计对冠边缘微渗漏的影响，以指导临床设计、操作，为临床减少微渗漏提供依据。方法：选取45颗离体牙，按不同肩台形式随机分为凹形肩台组、直角肩台组和斜面形肩台组。制作金属冠。每种肩台分别用3种粘结剂粘固，分别为Rely X Unicem树脂组、3M树脂改良型玻璃离子组和聚羧酸组。经冷热循环实验后氨化硝酸银染色，显影。沿牙体长轴切开，光学显微镜下观察冠修复体剖面染料渗透情况，并进行分级评估，对各组微渗漏程度进行统计分析。结果：相同肩台组中，树脂组微渗漏最少，聚羧酸组微渗漏最大（P<0.05）；相同粘结剂组中，凹形肩台组斜面形肩台组微渗漏无明显差别（P>0.05），均少于直角肩台组（P<0.05）。结论：树脂类粘结剂抗微渗漏性能优于玻璃离子类及聚羧酸类粘结剂，是全冠粘结的首选材料；凹形和斜面形肩台是减少微渗漏的理想肩台形式。

Influence of different cements and margin designs on marginal microleakage in metal crowns

Objective To study the influence of different cements and margin designs on marginal microleakage in metal crowns in order to guide clinical design,operation,and to provide basis for reducing microleakage in clinic.Methods 45 extracted human teeth were randomly divided into 3 groups.Teeth were prepared to the different margin finish lines,respectively chamfer,shoulder and bevel,and cast metal crowns.The crowns in each group were randomly subdivided into 3 subgroups according to the cements:Rely X Unicem resin adhesive,3M resin modified glass ionomer cement,and polycarboxylate cement.After thermocycling experiment,the teeth were dyed and developed,and the crowns were cut along the long axis of the teeth,then all specimens were evaluated under the microscope,and were graded using SPSS 17.0 software for statistical analysis on the degree of microleakage.Results With the same finish line,the resin adhesive demonstrated the least marginal microleakage,and polycarboxylate cement was associated with severe marginal microleakage(P<0.05);With the same cement,chamfer and bevel had no significant difference in microleakage(P>0.05),and they were both less than shoulder(P<0.05).Conclusion Resin adhesive luting system which is the first selection in clinic is better than glass ionomer cement and polycarboxylate cement;the chamfer and bevel which are the appropriate finish lines for decreasing microleakage are better than shoulder.