Efficacy of continuous apical negative ultrasonic irrigation (CANUI) in penetration of simulated lateral canals in extracted teeth

Pablo Castelo-Baz,Juan Seoane-Romero,Francisco J Rodríguez Lozano,María J Ginzo-Villamayor,José Martín-Cruces,Benjamín Martín-Biedma,Ramón Miguéns Vila

doi:10.1038/s41598-021-90430-0

Abstract

The aim of this study was to evaluate the efficacy of continuous apical negative ultrasonic irrigation into simulated lateral canals and the apical third in straight and curved root canals. Two simulated lateral canals were created 2, 4 and 6 mm from the working length in 120 single-rooted teeth (6 canals/tooth, n = 360 straight, n = 360 curved). The teeth were randomly divided into 3 experimental groups: positive pressure irrigation (PPI) (n = 20); passive ultrasonic irrigation (PUI) (n = 20); continuous apical negative ultrasonic irrigation (CANUI) (n = 20). 20% Chinese ink was added to a 5% sodium hypochlorite solution and delivered into the root canals. The results showed a significantly higher (P < 0.05) penetration of irrigant into the lateral canals and up to working length in the CANUI group for straight and curved roots. CANUI improves penetration into the lateral canals and up to the working length of the cleared teeth in straight and curved roots.

Highlights

Apical periodontitis is a biofilm-related infection, and one of the primary goals of treatment is to kill or remove microbes from the root canal system[1]
Two important factors should be considered during irrigation: (a) whether the system can deliver irrigant to the entire root canal system, the apical third, and (b) whether it is capable of debriding areas not accessible by mechanical instrumentation, such as lateral canals and isthmuses[3,7,8]
Gutarts et al.[13] developed continuous ultrasonic irrigation (CUI) using an ultrasonically activated needle placed inside the root canal with a flow of NaOCl, enabling continuous replenishment

Summary

Introduction

Apical periodontitis is a biofilm-related infection, and one of the primary goals of treatment is to kill or remove microbes from the root canal system[1]. The most common irrigation method is the conventional type using an irrigating cannula with the front extremity or side coupled to a syringe This method is limited for cleaning the apical portion and areas such as isthmuses and lateral c anals[3,9]. Passive ultrasonic irrigation (PUI), which uses ultrasound to induce cavitation and acoustic waves, is used to agitate irrigating solutions, thereby improving irrigant properties and cleaning ability in anatomically complex areas[10,11] This approach may result in uncontrolled removal of dentin in straight root c anals[12]. Gutarts et al.[13] developed continuous ultrasonic irrigation (CUI) using an ultrasonically activated needle placed inside the root canal with a flow of NaOCl, enabling continuous replenishment Using this method, in vivo studies have shown high cleaning efficiency in areas inaccessible via instrumentation[7,14]. Various studies have supported the safety of negativepressure cleaning systems compared to irrigation with a syringe or ultrasonic irrigation[17,18]

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Conclusion