Can ultrasonography be used to determine working length in endodontic treatment? An in vitro study.

This study was conducted to evaluate efficacy of ultrasonography (USG) in determining working length in in-vitro conditions. Twenty five access cavities of maxillary incisor teeth were opened and actual working lengths (AWL) were measured with dental operating microscope. The working length were then measured with an electronic apex locator and USG. USG and apex locator measurements were statistically analyzed using one sample t-test and compared with AWL. The mean AWL measurment was 20.68 mm. USG measured the working length slightly longer (21.09 mm) than the measurements of apex locator (20.64 mm). Statistical analysis showed that the USG method provided similar measurements to electronic apex locators and with no statistical difference with actual working length (P < .05). USG emerges as a promising method for working length measurement that allows simultaneous visualization of root tip anatomy in cases where electronic apex locators may be insufficient and there is buccal cortical bone loss.

Efficacy of different irrigant activation devices in removing dentin debris from an artificial isthmus connecting curved canals.

The aim of this study was to evaluate the debridement efficacy of sonic irrigation (EDDY; VDW, Munich, Germany and EndoActivator; Dentsply-Sirona, Ballaigues, Switzerland) and ultrasonically activated irrigation (Irrisafe; Satelec Acteon, Merignac, France) in a simulated canal isthmus connecting curved canals. Transparent resin blocks were produced containing two curved canals connected with an isthmus. The isthmus was then filled with dentin debris. Three irrigant activation cycles were performed and the amount of remaining debris was compared analysing pictures taken after each activation cycle. Data were statistically analysed using one-way ANOVA and post hoc Tukey tests at a significance level of p < 0.05. EDDY showed greater efficiency in removing dentin debris from the simulated isthmus than the other techniques tested. An increase in the activation time enhanced the efficiency of both EDDY and ultrasonically activated irrigation in debris removal.

Investigation of the effectiveness of sonic, ultrasonic and new laser-assisted irrigation activation methods on smear removal and tubular penetration.

The aim of this study was to examine the effectiveness of different irrigation activation methods on smear layer removal and tubular penetration. One hundred-five distal roots of mandibular molar teeth in total; 50 for smear removal efficiency (n = 10) analysis using scanning electron microscopy (SEM), and 55 roots were used to examine tubular penetration using confocal laser scanning microscope (CLSM). Five different irrigation activation methods were used in this study; conventional needle irrigation (CNI), sonic irrigation device of EDDY, passive ultrasonic irrigation (PUI), PIPS and SWEEPS techniques, which are two different laser irrigation activation methods. The obtained data were statistically analyzed and the significance level was determined as p < 0.05. At the apical level, the cleanest canal walls were observed when laser methods PIPS and SWEEPS were used, while in the middle third, there was no difference in smear removal efficiencies between all groups except for the CNI (p > 0.05). Penetration depths and percentages increased from apically to coronally in all groups. The PUI and EDDY generally showed similar penetration depths and percentages to the CNI, except at the coronal root level (p > 0.05). In all groups, when PIPS was used, it showed greater penetration depth and percentage (p < 0.05). PIPS and SWEEPS techniques showed lowest and similar smear scores compared to PUI and EDDY in the apical area where access and effectiveness of the irrigation solution are difficult.

Effect of EDDY and manual dynamic activation techniques on postoperative pain in non-surgical retreatment: a randomized controlled trial.

BACKGROUND: During non-surgical retreatment process, the products such as dentin debris, root canal fillings, irrigation solutions, microorganisms and remaining pulp tissues can extrude to the apical area and can cause the postoperative pain and flare-up. Thus, the aim of this study was to evaluatethe effect of EDDY and manual dynamic activation (MDA) techniques on postoperative pain (PP) associated with retreatment. METHODS: Ninety patients scheduled for retreatment were treated at a single visit. Non-vital mandibular premolar teeth diagnosed with asymptomatic apical periodontitis were included in this study. The patients were divided into two groups (n = 45) on the basis of the need for additional irrigation activation procedures (EDDY and MDA). The patients' post-treatment pain levels were asked to rate the intensity of their pain on a 10-point numerical rating scale (NRS) at the 12th, 24th, 48th, and 72nd h and 7 days.The data were analyzed using the chi-square and Wilcoxon signed-rank test was used for within-group comparisons and Mann Whitney U test was used to compare the groups by time period. RESULTS: The difference in postoperative pain intensity between two groups was statistically significant at 12, 24, 48, and 72 h (p < 0.05). There was no significant difference at 7 days. Moreover, no statistically significant difference was found between the two groups in terms of gender and analgesic medication intake (p > 0.05). Pain intensity after the treatment was lesser in the MDA groupthanin the EDDY group at 12, 24, 48, and 72 h. CONCLUSION: This study could lead us to conclude that the two activation systems can be used during endodontic retreatment with no difference at PP 7 days later. However, a comparison of the groups indicated that the EDDY resulted in significantly more PP at 12, 24, 48, and 72 h. Trial registration ClinicalTrials.gov Identifier: NCT04726670.

Investigation of the effect of indirect pulp capping materials on dentin mineral density

Aim: To evaluate the potential of inducing mineral density changes of indirect pulp capping materials applied to demineralized dentin. Methods: A total of 50 cavities were prepared, 5 in each tooth, in extracted ten molars without caries, impacted or semi-embedded. The cavities were scanned by microcomputed tomography (µ-CT) after creating artificial caries by microcosm method (pre-treatment). Each cavity was subjected to one of 5 different experimental conditions: control (dental wax), conventional glass ionomer cement (Fuji IX GP Extra), resin-modified calcium silicate (TheraCal LC), resin-modified calcium hydroxide (Ultra-Blend Plus), MTA (MM-MTA) and the samples were kept under intrapulpal pressure using simulated body fluid for 45 days. Then, the second µ-CT scan was performed (post-treatment), and the change in dentin mineral density was calculated. Afterward, elemental mapping was performed on the dentinal surfaces adjacent to the pulp capping agents of 5 randomly selected samples using energy dispersive X-ray spectroscopy (EDS) apparatus attached to a scanning electron microscope (SEM). The Ca/P ratio by weight was calculated. Friedman test and Wilcoxon Signed Ranks test were used to analyze the data. Results: There was a significant increase in mineral density values of demineralized dentin after treatment for all material groups (p<0.05). Resin-modified calcium silicate had similar efficacy to MTA and conventional glass ionomer cement, but was superior to resin-modified calcium hydroxide in increasing the mineral density values of demineralized dentin. Conclusions: Demineralized dentin tissue that is still repairable can be effectively preserved using materials with remineralization capability

Mechanical Properties of the New Generation RACE EVO and R-Motion Nickel-Titanium Instruments.

This study aimed to evaluate and compare the dynamic cyclic fatigue, torsional and bending resistance of two novel RACE EVO (FKG Dentaire SA, La Chaux de Fonds, Switzerland) and R-Motion (FKG) nickel−titanium instruments with traditional RaCe (FKG) instruments. RACE EVO, R-Motion and RaCe instruments with a size of 25 and taper of 0.06 were used. A dynamic cyclic fatigue test was used to assess the time to fracture. The fractured surfaces were further analyzed using scanning electron microscopy at ×350 and ×3000 magnifications. A torsional resistance test was performed to measure the maximum torsional strength and angle of rotation. Phase transformations with temperature were evaluated using differential scanning calorimetry. The results were statistically analyzed with a Kruskal−Wallis test at a 5% significance level. R-Motion had the highest time to fracture and the lowest torsional and bending resistance, whereas RaCe had the lowest time to fracture and the highest torsional and bending resistance (p < 0.05). In relation to the angle of rotation, RACE EVO instruments had the highest deformation capacity followed by R-Motion and RaCe instruments (p < 0.05). The greater cyclic fatigue resistance and lower torsional and bending resistance results indicate that the novel R-Motion and RACE EVO instruments are less rigid and more flexible than RaCe instruments.

Postoperative pain after SWEEPS, PIPS, sonic and ultrasonic-assisted irrigation activation techniques: a randomized clinical trial.

To investigate the efficacy of a new laser irrigation activation system [shock wave-enhanced emission photo-acoustic streaming (SWEEPS)] in terms of postoperative pain after primary root canal treatment compared with other techniques, namely photon-induced photo-acoustic streaming (PIPS), sonic system with EDDY, passive ultrasonic system (PUI), and manual dynamic activation (MDA). Two hundred patients with symptomatic irreversible pulpitis in mandibular premolar teeth were enrolled and randomly allocated to five different irrigation activation groups (n = 40) after chemo-mechanical root canal preparation. For irrigation activation, the SWEEPS and PIPS tips were attached to the Er-YAG laser system in the respective groups, while the Irrisafe tip was used in the PUI group and the EDDY tip in the sonic group. In the MDA group, irrigation was agitated with the master gutta-percha cone. At postoperative hours 8, 24, and 48 and on day 7, pain intensity was evaluated using the 10-mm Visual Analog Scale (VAS) and analgesic intake was recorded. The Kruskal-Wallis test was used to analyze the VAS scores, and pain prevalence and analgesic intake were examined with the Pearson's chi-square test at the 5% significance level. The PIPS and SWEEPS groups had the lowest level and prevalence of pain when compared to the remaining groups (P < 0.001). The PUI, sonic and MDA groups did not differ in terms of pain scores at hours 8 and 48 (P > 0.05). On day 7, the highest score and pain prevalence were recorded in the MDA group (P < 0.001). There was no difference between the groups in terms of analgesic intake (P > 0.05). Laser-activated irrigation systems provided lower postoperative pain scores and levels compared to the other activation systems. The MDA group had the highest pain scores and incidence at the end of the seventh day.

Postoperative pain after different irrigation activation techniques: a randomized, clinical trial.

The aim of this study was to assess the effectiveness of irrigation activation techniques on postoperative pain (PP) in mandibular premolar teeth with irreversible pulpitis after single-visit endodontic treatment. A total of 160 patients with symptomatic irreversible pulpitis were included in this prospective randomized clinical study. Four different activation methods were used in mandibular premolar teeth. In group 1, teeth were irrigated with side-port endodontic needles (NI) without any agitation; in groups 2 and 3, sonic activation was performed using EDDY and EndoActivator (EA), respectively; and in group 4, passive ultrasonic irrigation (PUI) was used. Patients' analgesic intake-as well as pain intensity during and after treatment-were recorded at 8, 24, 48 h and 7 days. The data relating to age, sex and analgesic intake was evaluated using the Chi-square test and the preoperative pain and PP intensity at different time intervals was evaluated with the Kruskal-Wallis test at a 5% significance level. Highest PP was recorded at 8 h, pain intensity decreased in all groups by the time. Pain in the NI group was found higher than that of EDDY group at 24 h (P < 0.05). EA and PUI had caused mild pain and had similar pain scores at 24 h. (P > 0.05). No statistically difference was found among the groups with regard to analgesic intake (P > 0.05). Although there were slight differences in PP levels between the groups at 24 h, pain levels decreased in all groups after 24 h. Activation of the irrigation solution did not make any difference in terms of PP after 24 h.

Cyclic fatigue resistance of reduced-taper nickel-titanium (NiTi) instruments in doubled-curved (S-shaped) canals at body temperature.

Background. This study was conducted to compare the cyclic fatigue resistance of VDW.ROTATE, TruNatomy Prime, HyFlex CM, and 2Shape nickel-titanium (NiTi) rotary instruments in double-curved canals in a simulated clinical environment. Methods. Eighty NiTi files were used for the fatigue testing in stainless steel canals compatible with instrument sizes until fracture occurred (n=20): VDW.ROTATE (04./25#), TruNatomy Prime (04./26#), HyFlex CM (04./25#) and 2Shape TS04./25#( 1). For each instrument, the number of cycles to fracture (NCF) was calculated, and the fractured fragment length (FL) was measured. To verify that the files were fractured due to cyclic fatigue, the fractured surfaces of the files were evaluated under a scanning electron microscope. Data were statistically analyzed using the Kruskal-Wallis and Student's t-tests at the %95 confidence level. Results. The failure of the files due to cyclic fatigue was first seen in the apical curvature before the coronal curvature (P<0.05). The highest fatigue resistance was observed in VDW.ROTATE and HyFlex CM files in both curvatures (P<0.05). There were no significant differences in the fatigue resistance between the HyFlex CM and VDW.ROTATE files or between the 2Shape and the TruNatomy files (P>0.05). There was no difference in the fractured lengths of the files between the apical and coronal curvatures (P>0.05). Conclusion. In artificial S-shaped root canals, VDW.ROTATE and HyFlex CM files exhibited higher fatigue resistance compared to 2Shape and TruNatomy files.

Comparison of the cyclic fatigue resistance of VDW.ROTATE, TruNatomy, 2Shape, and HyFlex CM nickel-titanium rotary files at body temperature.

OBJECTIVES: This study aims to compare the cyclic fatigue resistance of VDW.ROTATE, TruNatomy, 2Shape, and HyFlex CM nickel-titanium (NiTi) rotary files at body temperature. MATERIALS AND METHODS: In total, 80 VDW.ROTATE (25/0.04), TruNatomy (26/0.04), 2Shape (25/0.04), and HyFlex CM (25/0.04) NiTi rotary files (n = 20 in each group) were subjected to static cyclic fatigue testing at body temperature (37°C) in stainless-steel artificial canals prepared according to the size and taper of the instruments until fracture occurred. The number of cycles to fracture (NCF) was calculated, and the lengths of the fractured fragments were measured. The data were statistically analyzed using a 1-way analysis of variance and post hoc Tamhane tests at the 5% significance level (p < 0.05). RESULTS: There were significant differences in the cyclic fatigue resistance among the groups (p < 0.05), with the highest to lowest NCF values of the files as follows: VDW.ROTATE, HyFlex CM, 2Shape, and TruNatomy. There was no significant difference in the lengths of the fractured fragments among the groups. The scanning electron microscope images of the files revealed typical characteristics of fracture due to cyclic fatigue. CONCLUSIONS: The VDW.ROTATE files had the highest cyclic fatigue resistance, and the TruNatomy and 2Shape files had the lowest cyclic fatigue resistance in artificial canals at body temperature.

Fracture strength of endodontically treated teeth restored with different fiber post and core systems.

The aim of this study was to investigate the effects of different post and core systems, CAD/CAM crown placement on fracture strength of endodontically treated mandibular premolar teeth. One hundred forty single-rooted premolar teeth were randomly divided into a control group and six experimental groups as follows: control group (Group 1); FiberSite post luting with Clearfil DC Core Plus (Group 2); RelyX Fiber post luting and core build up with Clearfil DC Core Plus (Group 3); RelyX Fiber post luting with Clearfil DC Core Plus and core build up with Filtek Bulk Fill Posterior (Group 4); specimens that received CAD/CAM crowns after the same procedures performed in Groups 2, 3, and 4, respectively (Groups 5, 6, and 7). Fracture strength tests were performed, and the failure modes were recorded. Data were statistically analyzed using one-way ANOVA and post hoc Tukey tests. The highest fracture resistance was observed in the control group and among the experimental groups in Group 4. Groups 3 and 5 showed similar fracture resistance followed by Group 2. The lowest fracture resistances were seen in the samples of Groups 6 and 7. While the fracture strength of Group 2 increased after the crown placement (Group 5), the fracture strength of Group 3 and Group 4 decreased (P < 0.05). While the specimens in Groups 1, 2, 3, and 4 predominantly showed favorable failure, unfavorable failure was more frequent in Groups 5, 6, and 7.

Cyclic fatigue resistance of HyFlex EDM, Reciproc Blue, WaveOne Gold, and Twisted File Adaptive rotary files under different temperatures and ambient conditions.

Background. This study examined the effects of changes in temperature and environmental conditions on the cyclic fatigue resistance of Reciproc Blue, HyFlex EDM, WaveOne Gold, and Twisted File Adaptive. Methods. Forty-five Reciproc Blue (25/.08), 45 HyFlex EDM (25/.08), 45 WaveOne Gold (25/.07), and 45 Twisted File Adaptive (25/.08) files were tested for cyclic fatigue at room temperature (20°C) in air and water and at body temperature (35°C) in water. All the instruments were rotated in artificial canals made of stainless steel with an inner diameter of 1.5 mm, 60° angle of curvature and a radius of curvature of 5 mm until fracture occurred; the time to fracture was recorded in seconds, using a digital chronometer. Mann-Whitney U test was used for the statistical analysis of data, with SPSS 21.0. Results. Cyclic fatigue resistance was significantly higher in all the groups in water at an ambient temperature of 20°C compared with air and water at temperatures of 20°C and 35°C, respectively (P<0.05). The intragroup analysis revealed that HyFlex EDM had the highest cyclic fatigue resistance, followed by Reciproc Blue, WaveOne Gold, and Twisted File Adaptive in both air and water at 20°C (P<0.05). HyFlex EDM exhibited the highest cyclic fatigue resistance in water at 35°C, whereas there was no significant difference between the other groups (P>0.05). Conclusion. Within the limitations of the present study, an increase in the ambient temperature significantly decreased the cyclic fatigue resistance of the tested NiTi files.

Effect of glide path preparation with PathFile and ProGlider on the cyclic fatigue resistance of WaveOne nickel-titanium files.

OBJECTIVES: The aim of this study was to investigate the effect of glide path preparation with PathFile and ProGlider nickel-titanium (NiTi) files on the cyclic fatigue resistance of WaveOne NiTi files. MATERIALS AND METHODS: Forty-four WaveOne Primary files were used and divided into four groups (n = 11). In the first group (0 WaveOne), the WaveOne Primary files served as a control group and were not used on acrylic blocks. In the 1 WaveOne Group, acrylic blocks were prepared using only WaveOne Primary files, and in the PF+WaveOne group and PG+WaveOne groups, acrylic blocks were first prepared with PathFile or ProGlider NiTi files, respectively, followed by the use of WaveOne Primary files. All the WaveOne Primary files were then subjected to cyclic fatigue testing. The number of cycles to failure was calculated and the data were statistically analyzed using one-way analysis of variance (ANOVA) and the Tukey honest significant difference multiple-comparison test at a 5% significance level. RESULTS: The highest number of cycles to failure was found in the control group, and the lowest numbers were found in the 1 WaveOne group and the PF+WaveOne group. Significant differences were found among the 1 WaveOne, PF+WaveOne, and control groups (p < 0.05). No statistically significant differences were found between the PG+WaveOne group and the other three groups (p > 0.05). CONCLUSION: Glide path preparation with NiTi rotary files did not affect the cyclic fatigue resistance of WaveOne Primary files used on acrylic blocks.

Effect of Sodium Hypochlorite and EDTA on Surface Roughness of HyFlex CM and HyFlex EDM Files.

The aim of the present study was to compare the effect of exposure to sodium hypochlorite (NaOCl) and ethylenediaminetetraacetic acid (EDTA) on the surface topography and roughness of HyFlex controlled memory (CM) and HyFlex electrical discharge machining (EDM) using atomic force microscopy (AFM). Twenty HyFlex EDM (25/.08) and 20 HyFlex CM (25/.06) files were divided into five groups (n = 4). One group served as a negative control group. The files in the other groups were exposed to 5.25% NaOCl and 17% EDTA solutions at 37°C for 5 and 10 min, respectively, and examined using AFM after each exposure. The data were analyzed using one-way ANOVA test. The lowest values were observed in the control group of HyFlex EDM files (p < .05). The highest values were observed in the HyFlex EDM and HyFlex CM files immersed in EDTA for 10 min (p < .05). In conclusion, the tested irrigants had a significant negative effect on the surface porosity of NiTi files. The immersion of NiTi files in irrigants during cleaning and sterilization procedures results in corrosion and surface deformation of the files, and this can lead to unexpected file fracture during clinical use. Thus, the investigation of effect of ethylenediaminetetraacetic acid (EDTA) and sodium hypochlorite (NaOCl) on surface topography of HyFlex files is important.

Push-out bond strength of intra-orifice barrier materials: Bulk-fill composite versus calcium silicate cement.

Background. The aim of this study was to compare the push-out bond strengths of calcium silicate-based ProRoot MTA and Biodentine cements and SureFil SDR and EverX Posterior bulk-fill composite resins. Methods. Twenty-four single-rooted maxillary central incisors were sectioned below the cementoenamel junction, and the root canals were instrumented using rotary files. Thereafter, a parallel post drill was used to obtain a standardized root canal dimension. The roots were randomly assigned to one of the following groups with respect to the intra-orifice barrier used: ProRoot MTA; Biodentine; SureFil SDR; EverX Posterior. Five 1-mm-thick sections were obtained from the coronal aspect of each root. Push-out bond strength testing was performed and data were analyzed with Kruskal-Wallis and post hoc Dunn tests (P<0.05). Results. SureFil SDR and EverX Posterior bulk-fill composite resins' bond strengths were significantly higher than ProRoot MTA and Biodentine calcium silicate cements. However, no statistically significant differences were observed between bulk-fill composite resins values and calcium silicate cement values. Conclusion. Within the limitations of present study, calcium silicate-based ProRoot MTA cement's push-out bond strength was lower than those of Biodentine, SureFil SDR and EverX Posterior materials.

Effect of Glide Path Creating on Cyclic Fatigue Resistance of Reciproc and Reciproc Blue Nickel-titanium Files: A Laboratory Study.

INTRODUCTION: The purpose of this article was to compare the cyclic fatigue resistance of Reciproc and Reciproc Blue files (VDW GmbH, Munich, Germany) that were used to prepare root canals of mandibular molar teeth with or without a glide path. METHODS: Sixty Reciproc R25 and 60 Reciproc Blue R25 files were used. The Reciproc and Reciproc Blue groups were divided into 3 subgroups (ie, as received condition, used without a glide path, and used with a glide path). All the instruments were rotated in a stainless steel artificial canal with an inner diameter of 1.5 mm, a 60° angle of curvature, and a radius of curvature of 5 mm until fracture occurred. The number of cycle to fracture was calculated, and the length of the fractured segments was measured. The Kruskal-Wallis test was performed to statistically analyze the data using SPSS 21.0 software (IBM Corp, Armonk, NY) at a 5% significance level. RESULTS: The cyclic fatigue resistance of as received condition Reciproc Blue files was found to be higher than as received condition Reciproc files (P < .05). Reciproc Blue files used for root canal preparation showed higher cyclic fatigue resistance than Reciproc files used for root canal preparation (P < .05). There was no statistically significant difference between Reciproc and Reciproc Blue files used with a glide path and without a glide path (P > .05). There was no statistically significant difference in the mean length of the fractured fragments of the instruments (P > .05). CONCLUSIONS: Within the limitations of this in vitro study, it was concluded that creating a glide path using ProGlider files had no effect on the cyclic fatigue resistance of RPC and RPC Blue files.

The effect of root canal preparation on the surface roughness of WaveOne and WaveOne Gold files: atomic force microscopy study.

OBJECTIVES: To examine the surface topography of intact WaveOne (WO; Dentsply Sirona Endodontics) and WaveOne Gold (WOG; Dentsply Sirona Endodontics) nickel-titanium rotary files and to evaluate the presence of alterations to the surface topography after root canal preparations of severely curved root canals in molar teeth. MATERIALS AND METHODS: Forty-eight severely curved canals of extracted molar teeth were divided into 2 groups (n = 24/each group). In group 1, the canals were prepared using WO and in group 2, the canals were prepared using WOG files. After the preparation of 3 root canals, instruments were subjected to atomic force microscopy analysis. Average roughness and root mean square values were chosen to investigate the surface features of endodontic files. The data was analyzed using one-way analysis of variance and post hoc Tamhane's tests at 5% significant level. RESULTS: The surface roughness values of WO and WOG files significantly changed after use in root canals (p < 0.05). The used WOG files exhibited higher surface roughness change when compared with the used WO files (p < 0.05). CONCLUSIONS: Using WO and WOG Primary files in 3 root canals affected the surface topography of the files. After being used in root canals, the WOG files showed a higher level of surface porosity value than the WO files.

Apically Extruded Debris during Root Canal Instrumentation with Reciproc Blue, HyFlex EDM, and XP-endo Shaper Nickel-titanium Files.

INTRODUCTION: The purpose of this study was to investigate the amount of apically extruded debris by Reciproc Blue (REC Blue; VDW, Munich, Germany), HyFlex EDM (HEDM; Coltene/Whaledent, Altstätten, Switzerland), and XP-endo Shaper (XPS; FKG Dentaire SA, La Chaux-de-Fonds, Switzerland) files during root canal preparation at body temperature. METHODS: Sixty extracted single-rooted mandibular premolar human teeth were randomly assigned to 3 groups (n = 20). The canals were instrumented using 1 of the following instruments: REC Blue, HEDM, or XPS. Apically extruded debris during instrumentation was collected into preweighed Eppendorf tubes. All the procedures were performed at 35°C. The amount of extruded debris was calculated by subtracting the weight value of the tooth-free apparatus from the postpreparation weight value. The data were analyzed using the Kruskal-Wallis test at a 5% significance level. RESULTS: All the instruments tested caused extrusion of some debris from the apical foramen. XPS extruded significantly less debris from the apex than REC Blue (P < .05). The difference among the HEDM group and the other groups was not significant (P > .05). CONCLUSIONS: Within the limitations of this in vitro study, the amount of apically extruded debris registered for the different files tested was REC Blue > HEDM > XPS, with a statistical difference only between XPS and REC Blue.

Cyclic fatigue resistances of Hyflex EDM, WaveOne gold, Reciproc blue and 2shape NiTi rotary files in different artificial canals.

The aim of the present study was to compare the cyclic fatigue resistances of HyFlex EDM (HEDM), WaveOne Gold (WOG), Reciproc Blue (RB), and 2Shape (TS) NiTi systems having different metallurgic properties. HEDM, WOG, RB, and TS instruments were rotated in artificial canals which were made of stainless steel with an inner diameter of 1.5 mm, 45°, and 90° angles of curvatures and a radius of curvature of 5 mm until fracture occurred, and the time to fracture (TTF) was recorded in seconds. Also, number of cycles to fracture was calculated (NCF). Data were statistically analyzed using Kruskal-Wallis and t test. The statistical significance level was set at P < 0.05. When comparing the TTF of all the instruments tested in the artificial canal with 45° curvature, RB had statistically the highest cyclic fatigue resistance followed by HEDM and TS (P < 0.05), while the WOG showed the lowest cyclic fatigue resistance (P < 0.05). In artificial canal with 90° curvature, RB showed a significantly higher cyclic fatigue resistance than the other tested files (P < 0.05), while there was no significant difference among the TS, WOG and HEDM groups (P > 0.05). When the NCF values were taken into consideration, HEDM reported a significantly higher cyclic fatigue resistance than TS in both canal curvatures analyzed (P < 0.05). Within the limitations of the present study, RB NiTi files showed statistically higher cyclic fatigue resistance in artificial canals with 45° and 90° than the other NiTi files tested.

Effect of Dynamic Immersion in Sodium Hypochlorite and EDTA Solutions on Cyclic Fatigue Resistance of WaveOne and WaveOne Gold Reciprocating Nickel-titanium Files.

INTRODUCTION: The purpose of this study was to evaluate the effect of sodium hypochlorite (NaOCl) and EDTA solutions on the cyclic fatigue resistance of WaveOne (WO) and WaveOne Gold (WOG) nickel-titanium reciprocating files. METHODS: A hundred WO (25/.08), and 100 WOG (25/.07) were randomly divided into 5 groups: group 1, no immersion; group 2, immersion in 5.25% NaOCl at 37°C ± 1°C for 5 minutes; group 3, immersion in 5.25% NaOCl at 37°C ± 1°C for 10 minutes; group 4, immersion in 17% EDTA at 37°C ± 1°C for 5 minutes; and group 5, immersion in 17 % EDTA at 37°C ± 1°C for 10 minutes. Then, the instruments were reciprocated in an artificial canal until fracture occurred, and the time to fracture was recorded. The data were statistically analyzed using 1-way analysis of variance and the Student t test via SPSS 21.0 software (IBM Corp, Armonk, NY) with the significance level set at P < .05. RESULTS: The cyclic fatigue resistance of the WOG was statistically higher than the WO in all the conditions tested (P < .05). There was no statistically significant difference among the different conditions tested in terms of cyclic fatigue resistance for both WO and WOG files (P > .05). Among the groups, there was no significant difference in the fracture lengths (P > .05). CONCLUSIONS: Within the limitations of the present study, it was determined that NaOCl and EDTA solutions did not have any effect on the cyclic fatigue resistance of WO and WOG files.