Effect of the Passive Ultrasonic Irrigation and the Apical Diameter Size on the Debridement Efficacy of Infected Root Canals: A Multivariate Statistical Assessment of Histological Data

Marcela Alcota,Claudia Díaz,Cristián Peñafiel,Ana Ortega-Pinto,Juan C Rivera,Germán Manríquez,Fermín E González,Jimena Osorio,Daniela Salazar

doi:10.3390/app11167495

Abstract

The removal of necrotic and vital pulp substrates and microorganisms and their toxins from the root canal system (RCS) has been found to be the basis for a successful endodontic treatment. In this study, our aim was to evaluate the effect of passive ultrasonic irrigation (PUI) on the elimination of the organic remnant tissue from infected, narrow and curved mandibular root canals during their instrumentation. For this purpose, mesiobuccal canals from mandibular first molars were instrumented with the RaCe rotary system, using PUI activation or conventional irrigation (CI) and two apical diameters (#25 and #35). The root canal cleanness of the samples was evaluated by microscopy and using a modified Langeland’s ordinal scale. Parametric and non-parametric statistical analyses and principal coordinates analysis (PCoA) of the samples were performed. When PUI was used, there was a significant reduction of the organic remnant in the apical enlargement of 25 at 2 mm from the apex (p < 0.001). After pooling the groups, regardless of the depth of the observation (2 and 4 mm from the apex), the pair #35 + PUI vs. #25 + CI showed statistically significant differences (p < 0.001). The effect of PUI explained 65% of the overall variance when compared with the CI samples. The use of PUI reduced the organic material of narrow infected and curved root canals with an apical enlargement of #25 and #35. When PUI is not used, a biomechanical instrumentation up to a diameter ≥#35 is recommended.

Highlights

The cleaning of the root canal system (RCS) is done with a chemicalmechanical preparation using endodontic instruments and irrigating the area profusely with disinfecting chemical solutions [1]
The basis for a successful endodontic treatment is the complete removal from the RCS [2] of both necrotic and vital pulp substrates, together with microorganisms and their toxins
The objective of this study was to evaluate the effect of passive ultrasonic irrigation (PUI) on the removal of the organic remnant tissue from narrow, infected and curved root canals during their instrumentation with apical enlargements of #25 and #35

Summary

Introduction

The cleaning of the root canal system (RCS) is done with a chemicalmechanical preparation using endodontic instruments and irrigating the area profusely with disinfecting chemical solutions [1]. The basis for a successful endodontic treatment is the complete removal from the RCS [2] of both necrotic and vital pulp substrates, together with microorganisms and their toxins. In this context, the complexity of the morphology of the RCS makes their complete mechanical debridement a major challenge for clinicians. One of the most important factors for the clinical success of an endodontic treatment is the proper preparation of the apical third of the root canal. These, in turn, may cause periapical inflammation, disfavouring tissue repair and resulting in the consequent failure of the treatment, especially in non-vital and infected teeth [5,6]

Objectives

Methods

Results

Conclusion