SMEAR LAYER REMOVAL WITH DIFFERENT CONCENTRATIONS OF EDTA-ETHYLENEDIAMINE MIXTURES

The purpose of this study was to observe the effectiveness of EDTA and ethylenediamine mixtures in removing the smear layer from prepared ro ot canal walls following instrumentation. Thirty-five freshly extracte d, single-rooted maxillary anterior teeth were used. After the prepara tion of access cavities and establishing the working length, the apica l foramen of each canal was sealed with casting wax. All canals were t hen sequentially enlarged with K-type files to size 50. The sample was divided into seven groups of five teeth. The teeth in the control gro up were irrigated with saline solution. The specimens in the other gro ups were irrigated with 10 and 20 ml of three different EDTA-ethylened iamine mixtures. A scanning electron microscopic evaluation of the can al walls following irrigation showed that the superficial layer was to tally removed and the openings of the dentinal tubules were patent. On ly at the coronal third of the teeth in group 4 and the apical thirds in groups 2 and 4 was a moderate smear layer observed. The most favora ble results were obtained with groups 5, 6, and 7. The results show th at the smear layer can be totally removed by using 10 ml of a four-to- three by volume mixture of EDTA and ethylenediamine for irrigation of instrumented root canals.