Effectiveness of rotary instrumentation technique using different endodontic irrigants

Objectives: The effects of different endodontic irrigants on a smear layer created by Profile.04 instruments were evaluated in vitro in the apical thirds of flattened root canals. Methods: Fifty human mature extracted mandibular incisors teeth with a single root canal and a closed apex were distributed randomly into five groups of 10 teeth each. Whilst cleaning and shaping up to a size 40 master apical file with a crown-down technique, the root canals were irrigated with 5.25% NaOCl (Group I); 5.25% NaOCl and 17% EDTAC final irrigation (Group II); 5.25% NaOCl and EDTA gel alternate irrigation (Group III); 2% chlorhexidine gel and distilled water alternate irrigation (Group IV); and 5.25% NaOCl alternate irrigation Glyde File Prep™ (Group V). The root canals were irrigated with 3 mL of each endodontic irrigant alternately, between each file size, including 3 mL of final irrigation. After chemomechanical preparation, the teeth were split longitudinally and prepared for examination by scanning electron microscopy. The cleaning capacity was observed by score. Results: The parametric test showed a significant difference at the level of 1% between the irrigant solutions. The 5.25% NaOCl, and 5.25% NaOCl with alternate irrigation Glyde File Prep™ were statistically similar (p>0.05), showing higher presence of smear layer covering dentin walls. The 5.25% NaOCl with 17% EDTAC final irrigation, 5.25% NaOCl with EDTA gel alternate irrigation, and 2% chlorhexidine gel showed absent smear layer with open dentinal tubules. Conclusions: The rotary technique was more efficient in cleaning mesial-distal flattened root canals when using 5.25% NaOCl with 17% EDTAC final irrigation, 5.25% NaOCl and EDTA gel alternate irrigation, and 2% chlorhexidine gel with distilled water alternate irrigation.