Objective To evaluate the effect of four different placement techniques on the edge sealing and compactness of mineral trioxide aggregate(MTA) using Portland cement(PC), and the impact of using conveyor on residual materials on the root canal wall. Methods Established large apical straight root canal model and trumpet-shaped straight root canal model. Using four different placement techniques(Gutta-percha, EndoActivator, direct ultrasonic and indirect ultrasonic) placement PC in two models. Then they were observed and scored under a stereomicroscope. Using delivery and plugger transport PC into large apical root canal model, then the PC that residual on the root canal wall was measured. Results In guttapercha group, large apical root canal was great than trumpet-shaped straight root canal(P
