Irrigant flow in the root canal during ultrasonic activation: A numerical fluid-structure interaction model and its validation.

Aim: The aim of the study was (a) to develop a three-dimensional numerical model combining the oscillation of a tapered ultrasonic file and the induced irrigant flow along with their two-way interaction in the confinement of a root canal. (b) To validate this model through comparison with experiments and theoretical (analytical) solutions of the flow.

Methodology: Two partial numerical models, one for the oscillation of the ultrasonic file and another one for the irrigant flow inside the root canal around the file, were created and coupled in order to take into account the two-way coupled fluid-structure interaction.

Present status and future directions - irrigants and irrigation methods.

Irrigation is considered the primary means of cleaning and disinfection of the root canal system. The purpose of this review was 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. Organization 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.

The Effect of the Ultrasonic Irrigant Activation Protocol on the Removal of a Dual-species Biofilm from Artificial Lateral Canals.

Introduction: Lateral canals are particularly challenging to clean and disinfect. The aim of this study was to compare the removal efficacy of a dual-species biofilm from a lateral canal model by different ultrasonic irrigant activation protocols in vitro.

Methods: Artificial root canal models with 270 simulated lateral canals were made of polydimethylsiloxane.

A critical analysis of research methods and experimental models to study irrigants and irrigation systems.

Irrigation plays an essential role in root canal treatment. The purpose of this narrative review was to critically appraise the experimental methods and models used to study irrigants and irrigation systems and to provide directions for future research. Studies on the antimicrobial effect of irrigants should use mature multispecies biofilms grown on dentine or inside root canals and should combine at least two complementary evaluation methods.

Methodological quality assessment criteria for the evaluation of laboratory-based studies included in systematic reviews within the specialty of Endodontology: A development protocol.

High-quality systematic reviews in the field of Dentistry provide the most definitive overarching evidence for clinicians, guideline developers and healthcare policy makers to judge the foreseeable risks, anticipated benefits, and potential harms of dental treatment. In the process of carrying out a systematic review, it is essential that authors appraise the methodological quality of the primary studies they include, because studies which follow poor methodology will have a potentially serious negative impact on the overall strength of the evidence and the recommendations that can be drawn. In Endodontology, systematic reviews of laboratory studies have used quality assessment criteria developed subjectively by the individual authors as there are no comprehensive, well-structured, and universally accepted criteria that can be applied objectively and universally to individual studies included in reviews.

Syringe Irrigation in Minimally Shaped Root Canals Using 3 Endodontic Needles: A Computational Fluid Dynamics Study.

Introduction: The aim of this study was to compare the irrigant flow in curved root canals prepared to various apical sizes by constant-taper or variable-taper instruments during syringe irrigation with 3 endodontic needles at 2 different flow rates.

Methods: Two matched curved mesial root canals of human mandibular molars were imaged by micro-computed tomographic imaging after preparation to apical size 20, 25, and 30/.06 taper either by constant-taper or variable-taper instruments.

PRILE 2021 guidelines for reporting laboratory studies in Endodontology: A consensus-based development.

Reproducible, skilfully conducted and unbiased laboratory studies provide new knowledge, which can inform clinical research and eventually translate into better patient care. To help researchers improve the quality and reproducibility of their research prior to a publication peer-review, this paper describes the process that was followed during the development of the Preferred Reporting Items for Laboratory studies in Endodontology (PRILE) 2021 guidelines and which used a well-documented consensus-based methodology. A steering committee was created with eight individuals (PM, RO, OP, IR, JS, EP, JJ and SP), plus the project leaders (PD, VN).

Biofilm removal from a simulated isthmus and lateral canal during syringe irrigation at various flow rates: a combined experimental and Computational Fluid Dynamics approach.

Aim: (i) To quantify biofilm removal from a simulated isthmus and a lateral canal in an artificial root canal system during syringe irrigation with NaOCl at different concentrations and delivered at various flow rates (ii) to examine whether biofilm removal is further improved by a final high-flow-rate rinse with an inert irrigant following irrigation with NaOCl. (iii) to simulate the irrigant flow in these areas using a computer model (iv) to examine whether the irrigant velocity calculated by the computer model is correlated to biofilm removal.

Methodology: Ninety-six artificial root canals with either a simulated isthmus or lateral canal were used.

Subcutaneous emphysema in patients undergoing root canal treatment: a systematic review of the factors affecting its development and management.

Background: Subcutaneous emphysema is an infrequent mishap during root canal treatment which, in rare cases, can lead to severe complications.

Aim: To systematically review the literature on the factors affecting the development of subcutaneous emphysema during root canal treatment, and on its management.

Data Sources: An electronic search was conducted in EMBASE (1947-2018), LILACS (1982-2018), PubMed (1950-2018), SciELO (1997-2018), Scopus (1970-2018), Web of Science (1900-2018) and two grey literature databases.

Ultrasonic Irrigant Activation during Root Canal Treatment: A Systematic Review.

Introduction: The aim of this study was to systematically review the evidence on the cleaning and disinfection of root canals and the healing of apical periodontitis when ultrasonic irrigant activation is applied during primary root canal treatment of mature permanent teeth compared with syringe irrigation.

Methods: An electronic search was conducted of the Cochrane Library, Embase, LILACS, PubMed, SciELO, and Scopus databases using both free-text key words and controlled vocabulary. Additional studies were sought through hand searching of endodontic journals and textbooks.

Cleaning of used rotary nickel-titanium files in an ultrasonic bath by locally intensified acoustic cavitation.

Aim: To compare the pre-sterilization cleaning of rotary Ni-Ti files of different sizes previously used a. ex vivo and b. clinically by a washer-disinfector, a regular ultrasonic bath, and the same ultrasonic bath in combination with a recently developed cavitation intensifying method.

Apical negative pressure irrigation versus syringe irrigation: a systematic review of cleaning and disinfection of the root canal system.

The aim of this study was to systematically review and critically analyse the published data on the treatment outcome (primary outcome) and on the cleaning and disinfection of root canals (secondary outcomes) achieved by negative pressure irrigation as compared to syringe irrigation. An electronic search was conducted in EMBASE, LILACS, PubMed, SciELO, Scopus and Web of Knowledge using both free-text keywords and controlled vocabulary. Additional studies were sought through hand searching of endodontic journals and of the relevant chapters of endodontic textbooks.

Uncontrolled Removal of Dentin during In Vitro Ultrasonic Irrigant Activation in Curved Root Canals.

Introduction: The aim of this study was to examine the effect of file type and activation time on the uncontrolled removal of dentin during in vitro ultrasonic irrigant activation in prepared curved root canals.

Methods: Seventy-two curved mesial root canals of human mandibular molars were prepared to size 35/.04 taper.

Uncontrolled Removal of Dentin during In Vitro Ultrasonic Irrigant Activation.

Introduction: The aim of this study was to evaluate uncontrolled removal of dentin during in vitro ultrasonic irrigant activation in prepared root canals using 2 different files.

Methods: Fifty-four human single-rooted teeth with straight root canals were prepared to size 35/.06 taper.

Observer variation in the assessment of root canal curvature.

Aim: To evaluate the inter- and intra-observer agreement between training/trained endodontists regarding the ex vivo classification of root canal curvature into three categories and its measurement using three quantitative methods.

Methodology: Periapical radiographs of seven extracted human posterior teeth with varying degrees of curvature were exposed ex vivo. Twenty training/trained endodontists were asked to classify the root canal curvature into three categories (<10°, 10-30°, >30°), to measure the curvature using three quantitative methods (Schneider, Weine, Pruett) and to draw angles of 10° or 30°, as a control experiment.

Porosity distribution in root canals filled with gutta percha and calcium silicate cement.

Objective: Gutta percha is commonly used in conjunction with a sealer to produce a fluid-tight seal within the root canal fillings. One of the most commonly used filling methods is lateral compaction of gutta percha coupled with a sealer such as calcium silicate cement. However, this technique may result in voids and worse, the filling procedures may damage the root.

Acoustic streaming induced by an ultrasonically oscillating endodontic file.

Ultrasonically activated irrigation is an advanced dental technique for irrigation of the root canal system during a root canal treatment. The basic cleaning mechanism is a result of acoustic streaming induced by an oscillating file, leading to mixing of the irrigant and pressure and shear stresses on the walls of the root canal. Here the induced acoustic streaming, pressure, and shear stress are investigated in a two-dimensional cross-section of the root canal, using a combination of theory, numerical predictions, and experimental validation through high-speed particle tracking velocimetry.

The effect of flow rate and agitation technique on irrigant extrusion ex vivo.

Aim: To evaluate (i) the effect of irrigant flow rate, needle type, needle insertion depth and apical constriction diameter and (ii) the effect of ultrasonic, sonic and manual dynamic agitation on irrigant extrusion using a recently introduced method.

Methodology: Thirty-two human teeth with a straight root canal were prepared to size 35, 0.06 taper and assigned to group A or B.

Formation and removal of apical vapor lock during syringe irrigation: a combined experimental and Computational Fluid Dynamics approach.

Aim: (i) To evaluate the effect of needle type and insertion depth, root canal size and irrigant flow rate on the entrapment of air bubbles in the apical part of a root canal (apical vapor lock) during syringe irrigation using experiments and a Computational Fluid Dynamics (CFD) model, (ii) to investigate whether the irrigant contact angle affects bubble entrapment, (iii) to examine if an established vapor lock can be removed by syringe irrigation.

Methodology: Bubble entrapment during irrigation of straight artificial root canals of size 35 or 50 was evaluated by real-time visualizations. The irrigant was delivered by a closed-ended or an open-ended needle positioned at 1 or 3 mm short of working length (WL) and at a flow rate of 0.

Effect of needle insertion depth and root canal curvature on irrigant extrusion ex vivo.

Introduction: The aim of this study was to evaluate the effect of needle type and insertion depth, apical preparation size, and root canal curvature on irrigant extrusion by using a recently introduced method.

Methods: Sixteen human teeth with a straight root canal (group A) and 16 with a moderately curved root canal (group B) were sequentially prepared to sizes 25 or 35, .06 taper and mounted on a plastic vial filled with distilled water to simulate a periapical lesion.

Measurement and visualization of file-to-wall contact during ultrasonically activated irrigation in simulated canals.

Aim: (i) To quantify in a simulated root canal model the file-to-wall contact during ultrasonic activation of an irrigant and to evaluate the effect of root canal size, file insertion depth, ultrasonic power, root canal level and previous training, (ii) To investigate the effect of file-to-wall contact on file oscillation.

Methodology: File-to-wall contact was measured during ultrasonic activation of the irrigant performed by 15 trained and 15 untrained participants in two metal root canal models. Results were analyzed by two 5-way mixed-design anovas.

Factors affecting irrigant extrusion during root canal irrigation: a systematic review.

The aim of the present study was to conduct a systematic review and critical analysis of published data on irrigant extrusion to identify factors causing, affecting or predisposing to irrigant extrusion during root canal irrigation of human mature permanent teeth. An electronic search was conducted in Cochrane Library, LILACS, PubMed, SciELO, Scopus and Web of Knowledge using a combination of the terms 'irrigant', 'rinse', 'extrusion', 'injection', 'complication', 'accident', 'iatrogenic', 'root canal', 'tooth' and 'endodontic'. Additional studies were identified by hand-searching of six endodontic journals and the relevant chapters of four endodontic textbooks, resulting in a total of 460 titles.

A new method for real-time quantification of irrigant extrusion during root canal irrigation ex vivo.

Aim: (i) To introduce a new method of quantifying extruded irrigant during root canal irrigation ex vivo. (ii) to evaluate the effect of periapical tissue simulation and pressure equalization and (iii) to determine the effect of needle type, apical preparation size and apical constriction diameter on irrigant extrusion.

Methodology: Sixteen human single-rooted teeth were sequentially prepared to sizes 25-45, 0.

The effect of needle-insertion depth on the irrigant flow in the root canal: evaluation using an unsteady computational fluid dynamics model.

Introduction: The aim of this study was to evaluate the effect of needle-insertion depth on the irrigant flow inside a prepared root canal during final irrigation with a syringe and two different needle types using a Computational Fluid Dynamics (CFD) model.

Methods: A validated CFD model was used to simulate irrigant flow from either a side-vented or an open-ended flat 30-G needle positioned inside a prepared root canal (45 .06) at 1, 2, 3, 4, or 5 mm short of the working length (WL).