Boutsioukis C, Arias-Moliz M T. Present status and future directions - irrigants and irrigation methods. Int Endod J 2022; DOI: 10.1111/iej.13739. Online ahead of print.

Sodium hypochlorite remains the primary irrigant of choice.

This review aimed to set the framework for the obstacles that irrigation needs to overcome, to critically appraise currently used irrigants and irrigation methods, to highlight knowledge gaps and methodological limitations in the available studies and to provide directions for future developments. Organisation of bacteria in biofilms located in anatomic intricacies of the root canal system and the difficulty to eliminate them is the main challenge for irrigants. Sodium hypochlorite remains the primary irrigant of choice, but it needs to be supplemented by a chelator. Delivery of the irrigants using a syringe and needle and activation by an ultrasonic file are the most popular irrigation methods. There is no evidence that any adjunct irrigation method, including ultrasonic activation, can improve the long-term outcome of root canal treatment beyond what can be achieved by instrumentation and syringe irrigation. It is necessary to redefine the research priorities in this field and investigate in greater depth the penetration of the irrigants, their effect on the biofilm and the long-term treatment outcome. New studies must also focus on clinically-relevant comparisons, avoid methodological flaws and have sufficiently large sample sizes to reach reliable conclusions.