[The balanced force and the GT-rotary technique in comparison with the non-instrumental technique (NIT)]

The aim of the study was to compare the cleansing effect of the latest modification of the non-instrumentation technique (NIT) to that of conventional instrumentation. The root curvature in 100 vital human molars was determined by a standardized X-ray procedure and the teeth were assigned to five groups with 20 teeth each with an equal distribution of the root curvature. The preparation methods were the Balanced Force technique and the GT Rotary technique. Each root was irrigated with 40 ml of 3% sodium hypochlorite. The other groups were irrigated by NIT during 2.5, 5 or 10 minutes, respectively. The remaining pulpal tissue was stained and the root canals were exposed longitudinally. The teeth were then evaluated using a microscope and an image analysis-system. The residual organic debris in the apical, middle and coronal sections of the root canals were assessed as a percentage of the corresponding total examined length. The cleansing effect of the NIT in the coronal and middle parts of the canal used for 5 and 10 minutes was significantly better (p < 0.05) compared to using the device for 2.5 minutes. The cleansing effect of the NIT in the coronal and middle parts of the canal used for 5 and 10 minutes was also significantly better (p < 0.05) compared to using the GT Rotary or Balanced Force techniques. Apically, the cleansing effect of the NIT used for 5 and 10 minutes and the GT Rotary technique was significantly better (p < 0.05) compared to using the Balanced Force technique or the NIT for 2.5 minutes. It was concluded that the cleansing effect of the latest modification of the Non-instrumentation Technology (NIT) was equivalent to or better than that of conventional instrumentation requiring significantly less time.