CLEANING OF OVAL CANALS USING ULTRASONIC OR SONIC INSTRUMENTATION

This study investigated the effect of direction of file oscillation on the amount of debris and smear remaining within oval canals. Sixty-fi ve lower premolars were allocated to six experimental groups (n = 10) and one control group (n = 5). Canals were prepared using Gates Glidde n burs and hand instruments. Preparations were completed using either an ultrasonic size 15 K file or a sonic size 15 shaper file. Three pre paration techniques were used: (a) file oscillation toward oval recess es within the canal, (b) file oscillation at right angles to the reces ses, and (c) rotational movement of handpiece. Canals were examined un der the scanning electron microscope and blindly scored for debris and smear layer. Log linear analysis revealed no significant difference ( p > 0.05) between sonic or ultrasonic instrumentation as to debris or smear layer remaining. File oscillation directed toward oval recesses left the least amount of debris (p < 0.05). Smear layer remained unaff ected by all techniques.