Effect of Rotary Instrumentation on Endotoxins Removal from Root Canals

Because of the high toxicity of endotoxin, developing periapical inflammation and bone-resorption, its removal or neutralization from infected root canals during endodontic treatment is important for the healing process of the periapical tissues. Objective: This study was conducted to investigate the ability of the chemomechanical preparation with 2.5% NaOCl + 17% EDTA and rotary NiTi system in removing endotoxins from the root canals of teeth with primary endodontic infection and apical periodontitis. Methods: Twenty-one root canals with necrotic pulps were selected. Samples were collected before (s1) and after chemomechanical preparation (s2) using paper points. The Limulus Amebocyte Lysate (LAL) -Turbidimetric kinetic assay (Pyrogent®-5000) was used to quantify endotoxins. Results: The LAL assay (Pyrogent®-5000) indicated that endotoxins were present in 100% of the root canals investigated (19/19) before (s1) and after chemo-mechanical preparation (s2), with a median value of 9.19 EU/mL (range, 0.0597 – 289 EU/mL). As a result of the chemomechanical preparation, LPS content was reduced to a median value of 0.228 EU/mL (range, 0.01 – 4.21 EU/mL). There was a significant difference in the median value of endotoxin detected before (s1) and after chemomechanical preparation (s2) (p<0.05). Analyses of the quantitative data revealed that the endotoxin content after chemomechanical preparation with 2.5% NaOCl + EDTA 17% and rotary NI-TI files (s2) was significantly reduced (98.06%) compared to that at s1 (p<0.05). Conclusion: Our findings indicate that chemomechanical preparation with 2.5% NaOCl + 17% EDTA and rotary NiTi files was effective in reducing endotoxins from the root canals of teeth with primary endodontic infection and apical periodontitis.

Supported by FAPESP (07/58518-4, 08/58299-3, 08/57551-0, 0857954-8) & CNPq (3470820/2006-3; 471631/2008-6; 302575/2009-0)