EFFICIENCY OF CHELATING IRRIGATION AGENTS FOR REMOVING A LUBRICATED DENTIN LAYER OF ROOT CANAL.

The study is aimed at investigating the smear layer, formed on the walls of dental root canals as a result of endodontic treatment, by using scanning electron microscope (SEM) and determining its removal and/or modification quality after applying water solution of 18% ethylenediaminetetraacetic acid (EDTA) and gel. 50 extracted teeth preliminary prepared using Step-Back technique has been studied. Experimental teeth were randomly divided into the following 3 groups: control group (20 teeth), study group I (15 teeth) and study group II (15 teeth), respectively, irrigated by water solution of 18% ethylenediaminetetraacetic acid (EDTA). SEM examination was carried out for 3 different areas of preliminary prepared separated dental roots: coronal, middle and apical portions. The entire study was based on the analysis of 900 electron microscope photo- images. SEM study revealed formation of the thick smear layer on the surface of root canal dentin, practically covering the openings of canal tubules. Both the water solution and/or gel of 18% ethylenediaminetetraacetic acid provided partial or complete removal of the mentioned smear layer; among them, EDTA 18% water solution appeared to be more effective for coronal and middle thirds of dental root (P<0.05). Removal of the smear layer from root canals by using the chelating agents was less effective in the apical third. Having studied these areas, the portions covered with the smear layer and blocked dentinal tubules on canal surfaces were revealed.