Thyme Essential Oil As an Antibacterial Irrigant in Root Canal Treatment: In Vitro Preliminary Study

Abstract

Irrigation is crucial in cleaning and disinfection of the root canal system, because endodontic instruments are unable to reach a large part of the root canal system (isthmuses, accessory canals, apical ramifications) and bacteria that can reside. Sodium hypochlorite (NaOCl) is currently used as irrigant in root canal therapies for its non-specific protheolytic and antimicrobial properties, but undesirable effects may be observed especially when used near the terminus of apical foramen. This study aims to evaluate antimicrobial properties of Thyme Essential Oil (TEO) used alone or in combination with NaOCl against different bacterial strains, especially Staphylococcus aureus and Streptococcus mutans. TEO non-cytotoxic concentration (9,28mg/mL) showed antimicrobial properties comparable to NaOCl after 1min of contact, both in presence of organic material (6% sheep blood). Moreover, the combination of TEO and NaOCl did not compromise their individual antimicrobial properties at the same time of contact. These data suggest that TEO could be used as antimicrobial irrigant in root canal therapies in association with NaOCl, to reduce concentration of NaOCl and its undesirable side effects. Due to the absence of cytotoxic effects at tested dilution, TEO could be safely used also near the terminus of apical foramen for its cytocompatibility.