Irrigation dynamics associated with positive pressure, apical negative pressure and passive ultrasonic irrigations: A computational fluid dynamics analysis

Abstract

Complexities in root canal anatomy and surface adherent biofilm structures remain as challenges in endodontic disinfection. The ability of an irrigant to penetrate into the apical region of a canal, along with its interaction with the root canal walls, will aid in endodontic disinfection. The aim of this study was to qualitatively examine the irrigation dynamics of syringe irrigation with different needle tip designs (open-ended and closed-ended), apical negative pressure irrigation with the EndoVac® system, and passive ultrasonic-assisted irrigation, using a computational fluid dynamics model. Syringe-based irrigation with a side-vented needle showed a higher wall shear stress than the open-ended but was localised to a small region of the canal wall. The apical negative pressure mode of irrigation generated the lowest wall shear stress, while the passive-ultrasonic irrigation group showed the highest wall shear stress along with the greatest magnitude of velocity.

Efficacy of irrigant activation techniques in removing intracanal smear layer and debris from mature permanent teeth: a systematic review and meta‐analysis

“…This concept is further reinforced by validated computational fluid dynamic studies such as Chen et al . () who found shear stresses and hydrodynamic pressures generated through CNI were more localized than those created by IATs. This is consistent with a large body of evidence that reports greater irrigant distribution via IATs (de Gregorio et al .…”

“…Additionally, no study found CNI to be significantly better than any of the aforementioned IATs in any segment of the canal. This concept is further reinforced by validated computational fluid dynamic studies such as Chen et al (2014) who found shear stresses and hydrodynamic pressures generated through CNI were more localized than those created by IATs. This is consistent with a large body of evidence that reports greater irrigant distribution via IATs , Munoz & Camacho-Cuadra 2012, Spoorthy et al 2013, Dhaimy et al 2016.…”

The effectiveness of various irrigation protocols on organic tissue removal from simulated internal resorption defects

“…As the shear stress is highest around the tip (Chen et al . ), if it was placed at the same level on the resorption cavities, the dissolution values obtained from PUI groups could be different. The results are in conflict with those of Keskin et al .…”

Effectiveness of supplementary irrigant agitation with the Finisher GF Brush on the debridement of oval root canals instrumented with the Gentlefile or nickel titanium rotary instruments

“…Irrigation of the root canal system using a needle and syringe does not generate sufficient hydrodynamic shear stresses to dislodge the biofilms or tissue that adhere to the root canal walls (Goode et al 2013, Chen et al 2014, Neelakantan et al 2016a. To counteract this disadvantage, irrigant agitation strategies have been suggested (Plotino et al 2016).…”