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.

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).

The effect of apical preparation size on irrigant flow in root canals evaluated using an unsteady Computational Fluid Dynamics model.

Aim: To evaluate the effect of apical preparation size on irrigant flow inside a root canal during final irrigation with a syringe and two different needles types, using a Computational Fluid Dynamics (CFD) model.

Methodology: A validated CFD model was used to simulate the irrigant flow from either a side-vented or a flat 30G needle positioned inside root canals having sizes of 25, 35, 45 and 55, all with a .06 taper, at 3 mm short of working length (WL).

The effect of root canal taper on the irrigant flow: evaluation using an unsteady Computational Fluid Dynamics model.

Aim: To evaluate the effect of root canal taper on irrigant flow inside a prepared root canal during final irrigation with a syringe and two types of needles, using a Computational Fluid Dynamics (CFD) model.

Methodology: A validated CFD model was used to simulate irrigant flow from either a side-vented or a flat 30G needle positioned inside size 30, .02 taper, 30, .

Irrigant flow in the root canal: experimental validation of an unsteady Computational Fluid Dynamics model using high-speed imaging.

Aim: To compare the results of a Computational Fluid Dynamics (CFD) simulation of the irrigant flow within a prepared root canal, during final irrigation with a syringe and a needle, with experimental high-speed visualizations and theoretical calculations of an identical geometry and to evaluate the effect of off-centre positioning of the needle inside the root canal.

Methodology: A CFD model was created to simulate irrigant flow from a side-vented needle inside a prepared root canal. Calculations were carried out for four different positions of the needle inside a prepared root canal.

Evaluation of irrigant flow in the root canal using different needle types by an unsteady computational fluid dynamics model.

Introduction: The aim of this study was to evaluate the effect of needle tip design on the irrigant flow inside a prepared root canal during final irrigation with a syringe using a validated Computational Fluid Dynamics (CFD) model.

Methods: A CFD model was created to simulate the irrigant flow inside a prepared root canal. Six different types of 30-G needles, three open-ended needles and three close-ended needles, were tested.

Rheological study of synovial fluid obtained from dogs: healthy, pathological, and post-surgery, after spontaneous rupture of cranial cruciate ligament.

In the present study synovial fluid (SF) obtained from the stifle joint of healthy adult dogs and of dogs after cranial cruciate ligament rupture was analyzed regarding its rheological characteristics according to the condition of the joint. The viscoelastic and shear flow properties were measured at 25 and 38 degrees C. The results showed that the healthy SF exhibits practically temperature independent viscosity curve and satisfactory viscoelastic characteristics, i.

Irrigant flow within a prepared root canal using various flow rates: a Computational Fluid Dynamics study.

Aim: To study using computer simulation the effect of irrigant flow rate on the flow pattern within a prepared root canal, during final irrigation with a syringe and needle.

Methodology: Geometrical characteristics of a side-vented endodontic needle and clinically realistic flow rate values were obtained from previous and preliminary studies. A Computational Fluid Dynamics (CFD) model was created using FLUENT 6.

Measurement of pressure and flow rates during irrigation of a root canal ex vivo with three endodontic needles.

Aim: To monitor ex vivo intra-canal irrigation with three endodontic needles (25, 27 and 30 gauge) and compare them in terms of irrigant flow rate, intra-barrel pressure, duration of irrigation and volume of irrigant delivered.

Methodology: A testing system was constructed to allow measurement of selected variables with pressure and displacement transducers during ex vivo intra-canal irrigation with a syringe and three different needles (groups A, B, C) into a prepared root canal. Ten specialist endodontists performed the irrigation procedure.

Influence of the flow velocity on a Kovasznay type vorticity probe.

The output signal of a Kovasznay type vorticity probe is in first-order approximation proportional to the longitudinal component of the vorticity omegax= partial differentialw/ partial differentialy- partial differentialv/ partial differentialz and does not depend on the two transverse components of the flow velocity v, w. An experimental investigation of the influence of all three fluctuating velocity components on the longitudinal vorticity signal showed that their influence may not be neglected. The error in the probe response caused by the longitudinal component of the flow velocity was easily corrected using the instantaneous longitudinal velocity component and digital measuring techniques.