Forces and efficacy in endodontic irrigation systems.

Measurements of the pressure necessary to activate three commercially available types of endodontic irrigation systems were obtained from an in vitro testing procedure. In addition, the irrigation process was observed in simulated 1 mm. diameter root canals prepared in clear acrylic. Except for one patented system, the force necessary to depress the plunger of an irrigation syringe was found to increase as the size of the needle decreased. the most effective irrigation was observed when the larger needles of a blunted, open-end design were inserted to the full length of the preparation.