To evaluate the effect of two different root canal therapy on postoperative pain of root canal preparation.

Patients need to do root canal treatment of 118 cases were randomly divided into two groups: group A (59), root canal working length of apical stop point located in the root tester instructions arc baseline on the highest point (Beep 35 times / min); group B (59), root canal working length of apical stop point located in the root tester instructions arc baseline nadir (Beep 65 times/min), pain visual simulation score (visual analogue scale, VAS) scores recorded root of two groups of patients with preoperative preparation and after 12 h, 1 d, 2 d, 3 d, 1 week pain situation tube.

In 118 cases, the total incidence rate of tooth pain was 18.6%, the A group was 16.9% (10/59), and the B group was 20.3% (12/59), and there was no significant difference between 2 groups (P ＞ 0.05 ). VAS of two groups had no statistical significance (P ＞ 0.05 ).

There was no significant difference for postoperative pain of the two kinds of apical stop preparations.