Effect of different methods of sterilization on the inactivation of bacterial endotoxin (LPS) in endodontic files

Abstract

This study evaluated the presence of lipopolysaccharide (LPS) in endodontic files after in vitro contamination with E. coli LPS and sterilization in dry heat or wet heat, with or without previous immersion in a Ca(OH)2 suspension. LPS was quantified using the Kinetic QCL™ test and data were analyzed statistically by the t-test. LPS was quantified only in the contaminated group, not submitted to any immersion or sterilization procedure (0.262±0.1296 endotoxin units/mL) (p=0.0003). In conclusion, both wet heat and dry heat sterilization were effective in inactivating LPS without the need of previous immersion of the files in a Ca(OH)2 suspension.