The trend of radiographic healing after root canal treatment in teeth with apical periodontitis based on cone-beam computed tomography: A 4-year longitudinal study.

Objectives: The aim of this study was to observe the radiographic healing of periapical lesions after root canal treatment via volumetric measurements based on cone-beam computed tomography (CBCT) over 4 years.

Methods: In total, 162 single-root teeth from patients with chronic periapical periodontitis who underwent primary root canal treatment were included in this retrospective study. Follow-up visits were scheduled at 1, 2, and 4 years after treatment.

Radiographic healing after a root canal treatment performed in single-rooted teeth with and without ultrasonic activation of the irrigant: a randomized controlled trial.

Introduction: The aim of this study was to compare the outcome of a root canal treatment with and without additional ultrasonic activation of the irrigant.

Methods: Single-rooted teeth with radiographic evidence of periapical bone loss were randomly assigned to 2 treatment groups. In both groups syringe irrigation was performed, and in one group the irrigant was also activated by ultrasound.

Localized removal of layers of metal, polymer, or biomaterial by ultrasound cavitation bubbles.

We present an ultrasonic device with the ability to locally remove deposited layers from a glass slide in a controlled and rapid manner. The cleaning takes place as the result of cavitating bubbles near the deposited layers and not due to acoustic streaming. The bubbles are ejected from air-filled cavities micromachined in a silicon surface, which, when vibrated ultrasonically at a frequency of 200 kHz, generate a stream of bubbles that travel to the layer deposited on an opposing glass slide.

Sodium chloride and potassium sorbate: a synergistic combination against Enterococcus faecalis biofilms: an in vitro study.

Incomplete disinfection of the root canal system is a major cause of post-treatment disease. This study aimed to investigate the disinfecting property of organic acid salts and sodium chloride (NaCl), in a double-hurdle strategy, on Enterococcus faecalis biofilms. First of all, the high-throughput resazurin metabolism assay (RMA) was used to test a range of organic acid salts.

Comparison of the cleaning efficacy of different final irrigation techniques.

Introduction: The aim of this study was to evaluate the removal of dentin debris from artificially made grooves in standardized root canals by 6 different final irrigation techniques.

Methods: Conventional syringe irrigation, manual dynamic activation (MDA) with tapered or nontapered gutta-percha (GP) cones, the Safety Irrigator system, continuous ultrasonic irrigation (CUI), and apical negative pressure (ANP) irrigation were tested ex vivo in 20 root canals with a standardized, debris-filled groove in the apical portion of one canal wall. After each irrigation procedure, the groove was photographed, and the residual amount of dentin debris was scored.

Irrigant flow beyond the insertion depth of an ultrasonically oscillating file in straight and curved root canals: visualization and cleaning efficacy.

Introduction: The purpose of this study was to evaluate the influence of the insertion depth of an ultrasonically oscillating file on the ability to remove dentin debris from simulated canal irregularities in an extracted tooth model of a straight root canal and its influence on the flow of irrigant in both straight and curved canals.

Methods: A tooth model with artificial depressions in 1 canal wall at 0.5, 2, 4, and 6 mm from the working length was used.

The influence of the ultrasonic intensity on the cleaning efficacy of passive ultrasonic irrigation.

Introduction: It is not clear whether increasing the ultrasonic intensity would enhance the cleaning efficacy of passive ultrasonic irrigation (PUI) inside a root canal. The aim of this study was to evaluate the effect of the ultrasonic intensity on PUI to remove dentin debris and whether there is any lateral effect beyond the ultrasonic tip.

Methods: Each of 15 in vitro root canal models with four standard depressions in the apical part of one canal wall were filled with dentin debris and received PUI repeatedly.

Resazurin metabolism assay for root canal disinfectant evaluation on dual-species biofilms.

Introduction: Endodontic infections are caused by polymicrobial biofilms. Therefore, novel root canal disinfectants should be evaluated not only on single-species biofilms but also on dual- or mixed-species biofilms. A simple, high-throughput assay is urgently needed for this.

An evaluation of the effect of pulsed ultrasound on the cleaning efficacy of passive ultrasonic irrigation.

Introduction: Multiple activations of the irrigant by using pulsed ultrasound may enhance the removal of dentin debris because of repeated acceleration of the irrigant. The aim of this study was to evaluate the effect of pulsed ultrasound on passive ultrasonic irrigation (PUI) in its ability to remove artificially placed dentin debris from a simulated apical oval extension within standardized root canals.

Methods: Each of 20 in vitro root canal models with a standard groove in the apical portion of one canal wall filled with dentin debris received PUI repeatedly, either without pulsation (group 1) or with pulsation (730 milliseconds on/100 milliseconds off in group 2, 400 milliseconds on/400 milliseconds off in group 3, and 100 milliseconds on/670 milliseconds off in group 4), corresponding to duty cycles of 100%, 88%, 50%, and 13%, respectively.

Influence of the oscillation direction of an ultrasonic file on the cleaning efficacy of passive ultrasonic irrigation.

Introduction: The cleaning mechanisms and characteristics of passive ultrasonic irrigation (PUI) are not yet completely understood. The aim of this study was to investigate whether the oscillatory direction of the ultrasonically driven file had an influence on dentin debris removal from artificially made grooves in standardized root canals.

Methods: Each of 20 ex vivo root canal models with a standard groove in the apical portion of one canal wall filled with dentin debris received PUI repeatedly, either with file oscillation toward the groove or with file oscillation perpendicular to the groove.

Evaluation of a sonic device designed to activate irrigant in the root canal.

Introduction: The aims of this study were to evaluate the removal of dentin debris from the root canal by sonic or ultrasonic activation of the irrigant and the physical mechanisms of sonic activation by visualizing the oscillations of the sonic tip, both inside and outside the confinement of the root canal.

Methods: Roots of 18 canines were embedded, split, and prepared into standardized root canals. A standard groove was cut on the wall of one half of each root canal and filled with the same amount of dentin debris before irrigation procedures.

Influence of Streptococcus mutans on Enterococcus faecalis biofilm formation.

Introduction: An important virulence factor of Enterococcus faecalis is its ability to form biofilms. Most studies on biofilm formation have been carried out by using E. faecalis monocultures.