AN IN-VITRO STUDY OF APICAL EXTRUSION OF SODIUM-HYPOCHLORITE DURING ENDODONTIC CANAL PREPARATION

One hundred fifty-three single rooted teeth were divided into four gro ups. Canals were cleaned and shaped using the balanced forces techniqu e. In one group of 50 teeth, irrigation was delivered with the irrigat ion needle deep within the root canal, In the other group of 51 teeth, the needle was placed passively in the coronal access cavity and the irrigation carried into the root canal during filing. The remaining 52 teeth in the control groups were treated in the same manner using dis tilled water as the irrigation solution. The concentration of sodium e xtruded apically was measured by means of atomic emission spectrophoto metry, and the volume of sodium hypochlorite extruded was calculated. Significantly more sodium hypochlorite was extruded apically during de ep delivery of the irrigation (p < 0.05). It is concluded that the use of a reservoir of irrigation in the coronal access cavity results in significantly less apical extrusion of irrigation solution than with d eep delivery.