[The effect of root canal irrigation and variance of apical foramen pressure by use of casing aspiration needle system in vitro].
The authors introduced casing aspiration needle system (CANS) to irrigating root canal. The effect of root irrigation on removing canal debris and the variance of apical foramen pressure on extracted teeth were compared between the conventional irrigation and CANS irrigation. The results indicated that the effect of root canal irrigation by CANS was much better than the conventional method (P < 0.01). CANS irrigation didn't produce pressure to apical foramen during root canal irrigation. However, in the conventional method, with irrigation needle inserted deeper and deeper in root cancal the pressure of apical foramen gets higher and higher.