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The aim of this study was to evaluate the effects of mechanized final irrigation protocols (XPE, XP-Endo Finisher; XPC, XP-Clean; and ECL, Easy Clean) compared to PUI (passive ultrasonic irrigation) on the debris incidence and open dentinal tubules, and their effects on the adhesion interface after 48 h and 6 months. One hundred twenty maxillary central incisors were submitted to chemical–mechanical preparation using a rotary instrument and 2.5% sodium hypochlorite. Specimens were distributed in 4 groups (n = 30) in accordance with the mechanized final irrigation protocol: XPE, XPC, ECL, or PUI. Forty specimens (n = 10/group) were submitted to SEM analysis to evaluate the residue incidence and dentin open tubules. The other specimens were obturated using Bio-C Sealer and submitted to push-out bond strength and adhesive failure mode evaluations in the cervical, middle, and apical thirds after 48 h or 6 months (n = 10/group). Only in the apical third, ECL presented the highest residue incidence and fewer open dentinal tubules when compared to the XPE, XPC, and PUI groups (p < 0.05). In the cervical and middle root thirds, no significant differences were observed regardless of the group evaluated (p > 0.05). After 48 h, ECL resulted in the lowest bond strength only in the apical third (p < 0.05), while the XPE, XPC, and PUI groups remained similar in the cervical and middle thirds (p > 0.05). At 6 months, all groups showed lower bond strength values regardless of the root third evaluated, but ECL showed the lowest bond strength in the apical and middle root thirds when compared to the other groups (p < 0.05). The ECL protocol did not provide adequate residue removal on the apical radicular third and negatively affected the longevity of endodontic obturation using a calcium silicate-based sealer. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate the effects of mechanized final irrigation protocols (XPE, XP-Endo Finisher; XPC, XP-Clean; and ECL, Easy Clean) compared to PUI (passive ultrasonic irrigation) on the debris incidence and open dentinal tubules, and their effects on the adhesion interface after 48 h and 6 months. One hundred twenty maxillary central incisors were submitted to chemical–mechanical preparation using a rotary instrument and 2.5% sodium hypochlorite. Specimens were distributed in 4 groups (n = 30) in accordance with the mechanized final irrigation protocol: XPE, XPC, ECL, or PUI. Forty specimens (n = 10/group) were submitted to SEM analysis to evaluate the residue incidence and dentin open tubules. The other specimens were obturated using Bio-C Sealer and submitted to push-out bond strength and adhesive failure mode evaluations in the cervical, middle, and apical thirds after 48 h or 6 months (n = 10/group). Only in the apical third, ECL presented the highest residue incidence and fewer open dentinal tubules when compared to the XPE, XPC, and PUI groups (p < 0.05). In the cervical and middle root thirds, no significant differences were observed regardless of the group evaluated (p > 0.05). After 48 h, ECL resulted in the lowest bond strength only in the apical third (p < 0.05), while the XPE, XPC, and PUI groups remained similar in the cervical and middle thirds (p > 0.05). At 6 months, all groups showed lower bond strength values regardless of the root third evaluated, but ECL showed the lowest bond strength in the apical and middle root thirds when compared to the other groups (p < 0.05). The ECL protocol did not provide adequate residue removal on the apical radicular third and negatively affected the longevity of endodontic obturation using a calcium silicate-based sealer.

Aim: This study aimed to compare the efficiency of continuous and intermittent irrigating methods on the removal of dentin debris from the simulated grooves and to evaluate the dynamics of irrigant using computational fluid dynamics (CFD). Methodology: Seventy-five extracted human permanent maxillary canines were selected. Access cavities were made, working length was determined, and canals were prepared by crown down technique. The teeth were split longitudinally and standard groove 2.0 mm in length was made in split halves and each groove was filled with dentin debris and the images were taken under a microscope (E200). The halves were re-assembled and divided into five groups based on different irrigation methods. Group 1: ultrasonic Irrigation with continuous flow for 3.0 min; Group 2: ultrasonic irrigation with continuous flow for 1.5 min; Group 3: ultrasonic irrigation with intermittent flow for 3.0 min; Group 4: ultrasonic irrigation with the intermittent flow for 1.5 min; and Group 5: syringe irrigation for 1 min. The root halves were again separated and re-evaluated for debris elimination after the irrigation protocol for all the groups separately. The effect of time and method of passive ultrasonic irrigation were compared. For the computational fluid analysis, a GAMBIT 2.2 (Ansys) software was used for mesh construction. FLUENT 6.2 (Ansys) software was used to set the boundary conditions and reconstruction of the canal; flow patterns and turbulence were graphically constructed. Results: The continuous irrigation methods were better at debris removal than intermittent irrigation flow methods. The CFD showed that the turbulence of flow of irrigant was dependent on the inlet velocity and pressure of the irrigant. Conclusion: Debris removal from the simulated grooves was better with continuous irrigation compared with intermittent irrigation. CFD study revealed that the turbulence that was affected by the velocity and pressure of the irrigant introduced and is a variable entity. [ABSTRACT FROM AUTHOR]

Aim: The aim of this study was compare the capacity of different irrigation protocols for debris removal from artificial grooves and assess the effectiveness of Easy Clean used in different kinematics by means of micro-CT. Methodology: Fifty acrylic prototyped maxillary incisors were instrumented and included in a muffle. The specimens were longitudinally sectioned, and a longitudinal groove was made on the inner surface of the root canal in one of hemisections, and the dentin debris was inserted into the grooves. The specimens were divided into five groups (n = 10): G1: Conventional with open-ended needle; G2: Conventional with double side-vented needle; G3: Easy Clean in reciprocating movement; G4: Easy clean in continuous rotation (ECCR); and G5: Passive ultrasonic irrigation (PUI). All specimens were scanned using microcomputed tomography before and after the irrigation technique and calculated the volume (mm³) of dentin debris. The paired t-test and post hoc Tukey test were the statistical tests used, with significance set at 5%. Results: There were no significant difference (P > 0.05) between PUI and ECCR. ECCR was significantly (P < 0.05) more effective than the groups of conventional irrigation techniques. Conclusions: PUI and ECCR favored the removal of a larger volume of dentin debris from the groove. [ABSTRACT FROM AUTHOR]

Aim: To evaluate the cleanliness of rotary prepared root canals when the irrigation needle was placed at full or half the working length. Materials and Methods: Forty-five root canals were collected from extracted human teeth and divided into three groups each group of fifteen roots. Group 1: Root canals were instrumented using Profile® system and irrigated with 3% EDTA and 0.5% NaOCl. Group 2: Root canals were instrumented in the same manner as group 1 and irrigated with 18% EDTA and 5.25% NaOCl and the tip of the irrigation needle was introduced to the full working length. Group 3: Root canals were instrumented in the same manner as group 2 except that the tip of the irrigation needle was introduced half the working length. The roots were sectioned longitudinally and evaluated for smear layer at coronal, middle and apical thirds of the canals under SEM. The results were analyzed using the Kruskal-Wallis test. Results: No statistically significant difference was found in the distribution of the scores between all groups. However, the scores in the apical part of group 1were significantly higher than the middle and the coronal areas. Conclusion: The placement depth of irrigation needle or concentration of irrigants solutions has no influence on the cleanliness of rotary prepared canals.

Introduction The aim of this study was to compare the effectiveness of Easy Clean (Easy Dental Equipment, Belo Horizonte, MG, Brazil) in continuous and reciprocating motion, passive ultrasonic irrigation (PUI), Endoactivator systems (Dentsply Maillefer, Ballaigues, Switzerland), and conventional irrigation for debris removal from root canals and isthmus. Methods Fifty mesial roots of mandibular molars were embedded in epoxy resin using a metal muffle; afterward, the blocks containing the roots were sectioned at 2, 4, and 6 mm from the apex. After instrumentation, the roots were divided into 5 groups ( n = 10) for application of the final irrigation protocol using Easy Clean in continuous rotation, Easy Clean in reciprocating motion, PUI, Endoactivator, and conventional irrigation. Scanning electron microscopic images were taken after instrumentation and after the first, second, and third activation of irrigating solution to evaluate the area of remaining debris with image J software (National Institutes of Health, Bethesda, MD). Results The protocol of 3 irrigating solution activations for 20 seconds provided better cleaning of the canal and isthmus. On conclusion of all procedures, analysis of the canals showed a statistical difference only at 2 mm; the Easy Clean in continuous rotation was more efficient than conventional irrigation ( P < .05). On conclusion of all steps, the largest difference was observed in the isthmus in which the Easy Clean in continuous rotation was more effective than conventional irrigation at the 3 levels analyzed and the Endoactivator at 4 mm ( P < .05). The PUI promoted greater cleaning than conventional irrigation at 6 mm ( P < .05). There was no statistical difference between Easy Clean in continuous rotation, Easy Clean in reciprocating motion, and PUI ( P > .05). Conclusions Irrigating solution activation methods provided better cleaning of the canal and isthmus, especially the Easy Clean used in continuous rotation. The protocol of 3 irrigating solution activations for 20 seconds favored better cleaning. [ABSTRACT FROM AUTHOR]

Introduction The purpose of this study was to determine the influence of dentin powder on the concentration, pH, and antimicrobial activity of sodium hypochlorite (NaOCl) alone and combined with etidronic acid (HEBP). Methods Biofilms of Enterococcus faecalis were grown on the surface of dentin blocks for 5 days and then exposed to 1% and 2.5% NaOCl alone or combined with 9% HEBP for 3 minutes in the absence and presence of dentin powder. The biovolumes of the biofilm were measured using confocal microscopy and the live/dead technique. The available chlorine and pH of the solutions were also measured. Nonparametric tests were used to determine statistical differences ( P < .05). Results The presence of dentin powder resulted in a reduction of the free available chlorine and pH in all the irrigating solutions; 1% NaOCl lost its antimicrobial activity completely in the presence of dentin powder. The antimicrobial activity was significantly reduced in the 2.5% NaOCl and 1% NaOCl/HEBP groups, and it was not affected in the 2.5% NaOCl/HEBP group. Conclusions The presence of dentin powder significantly decreased the available chlorine and antimicrobial activity of 1% NaOCl, 2.5% NaOCl, and 1% NaOCl/HEBP irrigating solutions. The antimicrobial activity of 2.5% NaOCl/HEBP was not affected by the dentin powder after a 3-minute contact time against E. faecalis biofilms. [ABSTRACT FROM AUTHOR]

Introduction The aim of this in vitro study was to compare the effectiveness of saline, 2.5% sodium hypochlorite, and 2% chlorhexidine, with or without passive ultrasonic irrigation (PUI), in debris removal from simulated canal irregularities within prepared root canals. Methods Ninety bovine lateral incisors were randomly divided into 3 main groups ( n = 30) based on the irrigant and prepared with hand files attached to an oscillating handpiece (NSK, Tokyo, Japan) up to a size #80 K-file. Next, the teeth were split longitudinally, and a standardized groove was prepared into the apical third and filled with dentin debris. After the halves were reassembled, they were placed in a muffle. Each main group was randomly subdivided into 2 groups ( n = 14) and was treated with different final irrigation protocols. In the sodium hypochlorite/PUI, chlorhexidine/PUI, and saline/PUI groups, the solution was ultrasonically activated 3 times for 20 seconds. In the remaining groups, PUI was not performed. Specimens were scored for debris removal and analyzed under a scanning electron microscope. Results An association was observed between the score of debris removal and protocols using PUI ( P < .05). No association was observed between the scores of debris removal and the irrigants ( P = .87). Conclusions Final irrigation protocols that used PUI were more effective in removing debris from simulated canal irregularities into the apical third than those that did not use it. [ABSTRACT FROM AUTHOR]

Abstract: 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. Results: There was no significant difference between the MDA with a nontapered GP cone, the Safety Irrigator, and the ANP irrigation. These techniques produced better cleaning efficacy than syringe irrigation (P < .005) but significantly worse than the MDA with a tapered cone (P < .05). CUI was significantly better than all the other techniques tested in this study (P < .001). Conclusions: CUI was the most effective technique in dentin debris removal from the apical irregularities, and syringe irrigation alone was the least effective. MDA technique was more effective with a tapered GP cone than with a nontapered one. [Copyright &y& Elsevier]

Abstract: 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. Ultrasonic-activated irrigation was performed with the file inserted 1, 2, 3, 4, or 5 mm short of the working length. Dye penetration and high-speed recordings of the flow in straight and curved canals showed the static and dynamic behavior of the flow during ultrasonic activation. Results: The overall cleaning efficacy decreased with increasing distance between the file and the apex, with the depressions next to the file and within 3 mm in front of the file being the cleanest. The flow observed from the visualization experiments matched this distance, suggesting a direct relation between flow and cleaning. The observed flow depth increased with increasing power setting; the curvature of the root canal had no influence on the flow depth. High-speed imaging showed a start-up phase with deeper fluid activation than in the steady phase afterward. Conclusions: The ultrasonically oscillating file could remove dentin debris up to 3 mm in front of the file tip, coinciding with the extent of the observed flow. The root canal curvature had no influence on the irrigant flow. [Copyright &y& Elsevier]

Abstract: 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. The most apical depression was localized apically from the ultrasonic tip. The highest intensity was applied in group 1, the lowest intensity was applied in group 3, and syringe irrigation was performed in group 4 as a control. Before and after irrigation, images of the canal wall with depressions were taken and compared. The removal of dentin debris in the depressions was categorized as clean or not clean. The data were analyzed by means of the chi-square test. The oscillation amplitude of the ultrasonic file at each intensity was recorded in vitro using time-resolved high-speed imaging. Results: Group 1 (highest intensity) exhibited significantly better cleaning than all the other groups (P < .05); no significant difference was found between the four levels of the depressions within any of the four groups. High-speed imaging showed that the amplitude of the oscillating file increased as the intensity went up, which leads to a higher velocity of the irrigant around the file. Conclusions: Higher ultrasonic intensity resulted in a higher amplitude of the oscillating file and, consequently, enhanced the cleaning efficacy of PUI. [Copyright &y& Elsevier]

Abstract: 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 (group1) 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. After each irrigation procedure, the amount of dentin debris in the groove was evaluated by taking photographs of the groove and scoring. The irrigation procedures were also visualized in vitro using high-speed imaging performed in glass root canal models. Results: The debris score was significantly lower only in group 3 (p = 0.023). The in vitro visualization showed increased streaming and cavitation during the start-up phase of each pulse. Conclusions: PUI with a pulsation pattern of 400 milliseconds on/400 milliseconds off and a duty cycle of 50% is more effective in removing dentin debris from a simulated apical oval extension in standardized root canals than continuous ultrasonic activation. Duty cycles of 13% and 88% showed no difference compared with continuous oscillation. [ABSTRACT FROM AUTHOR]

Abstract: 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. After each irrigation procedure, the amount of dentin debris in the groove was evaluated by photographs of the groove and by scoring. The oscillations of the ultrasonic file were also visualized in vitro by using high-speed imaging at a time scale relevant to the cleaning process, order 10 microseconds. Results: A nonparametric analysis showed significantly more dentin debris reduction when the file oscillated toward the groove (P = .002). High-speed imaging showed that the oscillation of the file is in a single plane, resulting in high-velocity jets emanating from the file tip in the direction of the oscillations. Conclusions: Oscillation of the ultrasonically driven file toward the groove is more effective in removing dentin debris from the groove than oscillation perpendicular to the groove, which can be related to the fact that there is a high-velocity jet from the file tip in a single direction following the file oscillation and a relatively slow inflow in the perpendicular direction. [Copyright &y& Elsevier]