HyFlex EDM Research Articles

Comparative Evaluation of Dentinal Microcrack Formation During Root Canal Preparation Using Different Rotary Files: An In Vitro Study

Background:The success of endodontic treatment depends on completely removing all vital and necrotic pulp tissue, microorganisms, and microbial toxins from the root canal. During the cleaning and shaping process, the canal is shaped through the interaction between instruments and the dentin walls. These interactions can create several temporary stress points within the dentin, which may lead to the development of dentinal defects, craze lines, or microcracks. As a result, the techniques employed for shaping root canals carry the risk of starting crack formation, which, under functional pressure, could progress into complete fractures. This study was aimed to compare and evaluate the incidence of dentinal microcrack formation during root canal preparation using ProTaper Universal, ProTaper Gold, NeoEndo Flex and Hyflex EDM files. Materials and Methods: A total of 95 freshly extracted single rooted premolars with single straight canal were selected and stored in normal saline. Each specimen was examined using dental operating microscope to exclude cracked samples. Specimens then decoronated using a diamond disc and water as a coolant to a standardized length of 14 mm. Canal patency was determined by passing 10 K file passively and the working length was established 1 mm short of the file length at which the file become visible at the apical foramen. Canal was then enlarged upto15 k size file. Teeth samples were then divided into 5 groups having 19 teeth each. Group 1: Control Group (Uninstrumented teeth), Group 2 : Protaper Universal, Group 3 : Protaper Gold, Group 4 : NeoEndo Flex ,Group 5 : Hyflex EDM. After completion of cleaning and shaping procedure (to a standard apical diameter of 25), canal was rinsed with distilled water. Root was then horizontally sectioned at 3 mm, 6 mm and 9 mm from the apex with diamond disc at low speed under water cooling. All the sections were evaluated under stereomicroscope for presence of cracks and images were recorded. Cracks were observed as lines extending from the root canal lumen to the dentin or from the outer surface into the dentin. Results: All the file systems used in this study showed dentinal microcracks. ProTaper Universal exhibited the highest percentage of dentinal defects, while Hyflex EDM displayed the lowest among the file systems used (ProTaper Universal, ProTaper Gold, NeoEndo Flex and Hyflex EDM). The defects were present more in the apical third (3 mm) as compared to 6 mm (middle third) and 9 mm (coronal third) sections

Shaping ability of HyFlex EDM and ProTaper Gold files with or without using glide path files: An in vitro study

Abstract Introduction: The necessity of using a glide path before the canal preparation is inconclusive. Therefore, this study aimed to assess the shaping ability of two rotary systems in the maxillary first molars’ first mesiobuccal canal (MB1), with or without employing the glide path files. Materials and Methods: The MB1 canals of 100 extracted molars were randomly prepared using either HyFlex EDM (HEDM) or ProTaper Gold (PTG) systems (n = 50 each). Half of the samples in each group were prepared using ProGlider (PG) or HyFlex EDM Glide (HEG). The cone-beam computed tomography scanning was conducted before and after the instrumentation. The canal transportation, centering ability, and remaining dentin thickness were evaluated and compared between the groups using the independent sample t-test and Mann–Whitney U-test (α =0.05). Results: Using HEDM compared to PTG led to greater centering ability at the sub-furcation area (P < 0.05), lower canal transportation at 2 mm below furcation (P = 0.025), and more dentin removed at the middle area (P = 0.011). The systems’ centering ability and canal transportation were comparable when path files were used. Utilizing HEG with HEDM decreased dentin removal at 2 mm below furcation (P = 0.045) and middle area (P = 0.008). Canal preparation with HEDM-HEG caused less dentin removal at 2 mm below furcation than PTG-PG (P = 0.007). Conclusions: The HEDM system outperformed PTG regarding centering ability in the sub-furcation areas and canal transportation 2 mm below the furcation. However, HEDM showed more dentin removal in the middle region than PTG, which was resolved when HEG was used. Therefore, using PathFile with the HEDM system might be suggested.

Comparative Evaluation of Surface Roughness of Different Rotary Nickel-Titanium (NiTi) Files After Autoclaving: An Atomic Force Microscopic Study.

Introduction Canal preparation is a critical step in endodontic therapy. Introducing nickel-titanium (NiTi) rotary instruments has significantly reduced the likelihood of errors in curved canals. However, due to their price, these instruments are often reused following autoclaving. The aim of this study is to compare and evaluate the surface characteristics of two designs of rotary NiTi files used in curved canals and subjected to multiple autoclaving cycles, utilizing an atomic force microscope for detailed analysis. Methods A total sample size of 24 files was taken, 12 files of Hyflex EDM (Coltene/Whaledent, Germany) files andWaveOne Gold (Dentsply Sirona, USA) fileswere then divided into four groups (n=6) as follows:Group I: Hyflex EDM control group;Group II: WaveOne Gold control group;Group III: Hyflex EDM experimental group; Group IV: WaveOne Gold experimental group. Sterilization using an autoclave was performed thrice for Groups I and II files. The files in Groups III and IV were used in simulated curved canals three times and autoclaved after each use. Atomic force microscopy was used to assess the surface roughness of the files after the first and third autoclave cycles. Results The results showed that, without statistical significance, Hyflex EDM exhibited the highest surface roughness after the first usage among the two file systems. Conclusion It can be concluded that both Hyflex EDM and WaveOne Gold files produced similar levels of surface changes when subjected to multiple usage and autoclaving cycles.

Quantitative evaluation of the apically extruded debris from root canals prepared by single-file rotary and reciprocating file systems: An in vitro study.

The aim is to investigate and compare the amount of apically extruded debris after root canal preparation using single rotary and reciprocating file system. Forty single-rooted human mandibular premolars with straight canals were randomly assigned to four groups (n = 10). The root canals were instrumented according to the manufacturers' instructions using single-rotary file systems Hyflex EDM (HEDM), One Shape (OS) and single-reciprocating file systems Wave OneGold (WOG) and OneRECI (OR). The apically extruded debris was collected in preweighed glass vials using the Myers and Montgomery method. After drying, the mean weight of the extruded debris was assessed using a microbalance. Multiple comparison between groups demonstrated that the mean weight of apically extruded debris in the HEDM group was significantly less compared to all other study groups, and the differences were statistically significant (P < 0.001). Under the condition of this study, all file systems caused apical debris extrusion. The mean apically extruded debris was significantly least in HEDM, followed by WOG, OneRECI and highest in the OS group.

Assessment of Vertical Force Generated with Single File Systems during Shaping of Constricted Root Canals.

This study aimed to evaluate the shaping force generated with OneShape (OS) and HyFlex EDM (HEDM) systems designed for single file shaping, in comparison with ProTaper Next (PTN). Maxillary premolar teeth received access cavity preparation and their canals were shaped with OS, HEDM, or PTN to size 25 according to manufacturer's instructions with consistent pressure on the files to give a gentle "in-and-out" movements of 2 mm amplitude. The canal shaping was completed with a total of three insertions. After each insertion, 1% NaOCl irrigation and recapitulation with K-file size 15 were performed. The vertical shaping force was measured using a force gauge (M5-20 Advanced Digital Force Gauge; Mark-10 Corporation, NY). The shaping time was analyzed by using a one-way analysis of variance (ANOVA) test and differences between the mean apical and coronal maximum force values were analyzed using the Kruskal-Wallis and Mann-Whitney U tests. The level of significance was set as 0.05. The magnitude of the vertical forces increased with successive advancements of the instruments within the canal. During canal shaping procedures in all groups, the apical and coronal maximum force values of the OS and HEDM ranged from 2.5 to 7.2 N and 1.3 to 2.9 N, respectively. PTN generated the lowest maximum apical forces during the second and third insertions (p < 0.05). HEDM generated significantly less maximum coronal forces than both OS and PTN during the first insertion while the use of OS was associated with the highest amount of force values in the second and third insertions (p < 0.05). In terms of shaping time, no significant differences were detected among the three tested systems (p = 0.606). The tested single file systems were associated with higher shaping forces in the apical direction that were significant in the second and third insertions.

Postoperative Pain Following Single Visit Root Canal Treatment With Reciproc Blue And Hyflex EDM Instrumentation; A Prospective Randomized Clinical Trial

Objective: Single file systems with continuous rotation or reciprocation produced with many new technologies promising in terms of postoperative pain. The aim of this study was to investigate the efficacy of using novel Reciproc Blue (RBlue) and HyFlex EDM (HEDM) files on postoperative pain after single visit root canal treatment. Materials and Methods: 72 patients with asymptomatic pulp necrosis in mandibular molar and premolar teeth were included. The root canals were prepared using HEDM (n=29) or RBlue (n=28) and hand-instruments (n=15) in single visit. Pain presence using verbal rating scale (VRS) and analgesic intake were recorded after 24h, 48h, 72h and 7 days. Results: Postoperative pain at 24h and 48h was statistically higher at RBlue group than HEDM and control groups (p0.05).There was no difference between groups in terms of analgesic intake (p&gt;0.05). RBlue files were associated with higher incidence of postoperative pain and higher VRS scores than HEDM and hand-instruments. Conclusion: RBlue files working with reciprocating motion caused much more postoperative pain than HEDM files and manual files.

Comparative Evaluation of Action of RISA and Sodium Hypochlorite on the Surface Roughness of Heat Treated Single Files, Hyflex EDM and One Curve- An Atomic Force Microscopic Study

Aim: The aim of the study is to evaluate the action of RISA and Sodium hypochlorite on the surface roughness of heat treated single files, Hyflex EDM and One Curve using an Atomic Force Microscope.  Materials and Methods: A total of ten new files from each brand (Hyflex EDM and One Curve were taken. Before immersion , all the files were observed under Atomic Force Microscope to determine the surface roughness. Five files from Hyflex EDM were immersed in 5.25% sodium hypochlorite and five files were immersed in RISA solution. Five files from One Curve were immersed in 5.25 % sodium hypochlorite and the other five files were immersed in RISA solution. The dynamic immersion of the files were done by attaching it to an endomotor at constant speed [300 rpm] and torque [2.5 N Cm] into plastic tubes .After immersion, all the files were kept on the staging platform of AFM and 3mm section of the tip was examined for surface roughness.  Results: Within the limitations of this study, Hyflex EDM files immersed in sodium hypochlorite showed highest increase in surface roughness. Among the irrigant solutions used, increase in surface roughness was more for files immersed in Sodium hypochlorite as compared to files immersed in RISA solution.

Evaluation of cyclic fatigue behavior of RACE EVO rotary Files: In-vitro comparative study

IntroductionComparative evaluation of the newly introduced; RACE EVO file system to the currently well-performing file systems like HyFlex EDM OneFile, Vortex Blue, ProTaper Gold (PTG) with regards to the cyclic fatigue resistance. Materials&Methods.The endodontic rotary files under evaluation were segregated into four groups as follows:; RACE EVO, PTG, Vortex Blue, and HyFlex EDM OneFile. A detailed physical analysis of the cyclic fatigue resistance was performed in 15 files of each type (n = 60). Under the test conditions of 37 °C the test samples were subjected to continuous motion at the manufacturer recommended speed within an artificial curved canal until it fractured. For all the test samples, with the recording of time of fracture, calculation was done for number of cycles to fracture (NCF). In addition, the length of the fractured segment was determined. The fractured surface was further evaluated with scanning electron microscopic (SEM) images. ResultsHighest significance for NCF was seen in HyFlex EDM OneFile followed by the Vortex Blue, PTG, and; RACE EVO (p < 0.05) by analyzing the data statistically. Significant differences among the lengths of the fractured segments were evident among tested files, ranging between 4.73 and 6.3 mm (p < 0.05) with HyFlex EDM OneFile uniquely differentiating from the others showing the fracture at 6.3 mm. The common features of cyclic fatigue failure was further substantiated by SEM images. ConclusionsCompared to the HyFlex EDM OneFile, Vortex Blue, and PTG files; RACE EVO demonstrated significantly lower resistance to cyclic fatigue.

Postoperative Pain Following Single-visit Root Canal Treatment with Reciproc Blue and HyFlex EDM Instrumentation; A Prospective Randomized Clinical Trial

Postoperative Pain Following Single-visit Root Canal Treatment with Reciproc Blue and HyFlex EDM Instrumentation; A Prospective Randomized Clinical Trial

Evaluation of apical transportation and centering ability of three single-file systems in severely curved canals using micro-computed tomography

Background: This study aimed to compare the apical transportation and centering ability of One Curve, HyFlex EDM, and EdgeFile X1 in curved mesiobuccal and mesiolingual canals of mandibular first molars. Materials and Methods: In this in vitro experimental study, 60 mesiobuccal and mesiolingual canals of the mandibular first molars with a minimum length of 19 mm and 25°–40° curvature were randomly divided into three groups (n = 20) for root canal preparation with One Curve, HyFlex EDM, and EdgeFile X1. After access cavity preparation and confirming the glide path, the baseline micro-computed tomography (micro-CT) scans were obtained, and the root canals were instrumented with the respective systems according to the manufacturers’ instructions. Apical transportation and centering ability were assessed at 1, 3, 5, and 7 mm from the apex by comparing pre- and postinstrumentation micro-CT scans. One-way ANOVA, independent t-test, and Duncan's post hoc test were used to statistically compare the groups, and data were analyzed by SPSS version 24 (alpha = 0.05). Results: The three groups were not significantly different regarding apical transportation at 5 and 7 mm from the apex (P &gt; 0.05). At 1 mm level, One Curve caused significantly lower apical transportation; while, at 3 mm level, HyFlex EDM resulted in significantly higher apical transportation (P &lt; 0.05). No significant difference was noted in the centering ability of the three groups at 1, 3, and 5 mm from the apex (P &gt; 0.05). At 7 mm level, EdgeFile X1 showed significantly lower centering ability (P &lt; 0.05). Conclusion: One Curve caused lower canal transportation in the apical third compared with EdgeFile and HyFlex EDM, but no significant difference was noted among the three in the coronal third of the roots.

Substance P/calcitonin gene-related peptide and their receptors expression in human periodontal ligament after root canal preparation with five different systems.

The purpose of this study was to quantify the effect of five different root canal preparation instruments on Substance P (SP), Calcitonin gene-related peptide (CGRP) and their receptors expression in healthy human periodontal ligament. STROBE guidelines were used to design a study using 60 periodontal ligament samples obtained from healthy lower premolars where extraction was indicated for orthodontic reasons. Prior to extraction 40 of these premolars were equally divided into four groups and root canals were prepared using different systems: Mtwo, Reciproc Blue, HyFlex EDM and Plex-V. Ten premolars were prepared with hand files and served as a positive control group. The remaining 10 premolars where extracted without treatment and served as a negative control group. All periodontal ligament samples were processed to measure the expression of SP, CGRP and their receptors by radioimmunoassay. Kruskal-Wallis and Duncan tests were performed to determine statistically significant differences between the groups for each variable. Greater expression of all the peptides measured were found in the hand-file preparation group, followed by the Reciproc Blue, Mtwo, HyFlex EDM and Plex-V groups. The lower SP, CGRP and their receptors values were for the intact teeth control group. Kruskal-Wallis test showed statistically significant differences amongst groups (p < .001). Dunn post-hoc tests showed statistically significant differences in SP, CGRP and their receptors expression between the intact teeth and the hand-file and Reciproc Blue groups. Hand-file group showed significant differences with the other groups, except with Reciproc Blue, where no differences were observed in any of the peptides measured. Finally, no differences were observed between Plex-V and HyFlex in any of the peptides measured. Root canal preparation with hand files and Reciproc Blue generates the highest expression of SP, CGRP, NK1 and CGRP1R in human periodontal ligament, whilst Plex-V and HyFlex maintain the basal expression of neuropeptides and their receptors. Mtwo showed intermediate results between Reciproc Blue and HyFlex.

Assessment of Debris Extrusion in Curved Canals: An In Vitro Analysis of Various Single-File Endodontic Instrumentation Systems.

Rotary single-file endodontic systems are commonly used for root canal treatment. However, very few studies have evaluated the apical extrusion of debris generated by these systems during canal preparation at normal body temperature in laboratory conditions. The aim of this study was to evaluate the amount of apically extruded debris caused by seven different single-file endodontic instrumentation systems at body temperature in mandibular molar teeth with curved root canals. One hundred forty mandibular first permanent molars were randomly divided into seven groups (n = 20) to be prepared by one of the following systems at 35°C: Reciproc Blue (REC Blue), WaveOne Gold (WOG), One Reci (OR), Neoniti, HyFlex EDM (HEDM), One Curve (OC), or XP Shaper (XPS). Debris was collected into preweighted Eppendorf tubes. The weight of the extruded debris was recorded by subtracting the weight of the tooth-free apparatus from the post-procedure weight. Data were analyzed by one-way ANOVA and Tukey's tests (p < 5%). REC Blue, WOG, and OR groups extruded significantly more debris from the apex than XPS, OC, and Neoniti groups (p < 0.05). No significant difference was observed among the XPS, OC, Neoniti, and HEDM groups (p > 0.05). All the instruments were associated with debris extrusion. However, REC Blue, WOG, and OR extrude significantly more debris than other instruments. The amount of debris with different files was REC Blue > OR > WOG > HEDM > OC > Neoniti > XPS. XPS, Neoniti, and OC caused significantly less extrusion of debris than REC Blue, WOG, and OR.

A new method to measure the mechanical properties of rotary endodontic Ni-Ti files: Measurement of 6-axis force/torque and automatic root canal preparation.

The purpose of this study was to develop a new instrument to measure the mechanical properties of rotary endodontic Ni-Ti files (ProTaper Gold F2, ProTaper Ultimate F2, and HyFlex EDM Onefile), and to evaluate the overall utility of the device. The instrument was capable of analyzing the 6-axis force/torque generated by the files during cyclic dynamic movement in a metal curved artificial root canal, and doing automatic cyclic dynamic filing in a resin root canal with a preset vertical force limit by adopting a negative feedback mechanism. By analyzing the 6-axis force/torque, we were able to estimate the position and contact points of the files in the curved root canal. ProTaper Gold showed the highest force/torque in all directions. HyFlex EDM had the highest hysteresis ratio, centering ratio value and NCF (number of cycles to fatigue fracture), while the lowest vertical force.

Influence of sealer and supplementary approach on filling material removal during endodontic retreatment.

Both root canal sealer-based and supplementary protocols may influence removal of filling material during endodontic retreatment. Mesial root canals of extracted mandibular molars were prepared using HyFlex EDM 25/.08, and filled with a calcium silicate sealer (Bio-C Sealer), or an epoxy resin (AH Plus), using the single cone technique (n = 12). Retreatment was performed using ProDesign Logic (PDL) RT and PDL 35/.05. The specimens were randomly divided into two experimental groups (n = 12), and the sealers were distributed similarly. A supplementary protocol was performed with PDL 50/.01 or XP-endo Finisher. Root canal transportation and volume, in addition to the remaining filling material percentage were evaluated using high-resolution (5 µm voxel size) micro-CT. Statistical analysis was performed using t-tests (α = 0.05). Root canals filled with AH Plus presented high residual filling material (p < 0.05). Both protocols decreased residual volume of filling material in the apical third (p < 0.05). PDL 50/.01 increased the apical root canal volume (p < 0.05). No difference was observed between the systems regarding canal transportation (p > 0.05). In conclusion, AH Plus is more difficult to remove from the apical third than Bio-C Sealer. PDL 50/.01 and XP-endo Finisher enabled greater removal of filling materials in the apical third, in the retreatment of curved root canals, without promoting apical transport.

Hyflex CM and EDM from Shape Memory to Control Memory.

The new era in endodontics has been established with the introduction of nickel titanium (NiTi) alloys, and later on the automation of mechanical preparation. By changing the phase transformation temperatures of NiTi alloy, the manufacturers alter the phase composition to have a NiTi with new mechanical properties. These mechanical properties can be achieved either by thermal, mechanical treatments or both. Moreover, many machining procedures (e.g. twisting, electrical discharge machining), were developed. The higher flexibility of thermomechanically treated NiTi alloys was found as the main advantages of these alloys with the improvement of cyclic fatigue resistance when compared to conventional NiTi. Austenitic alloys have superelastic properties due to stress-induced martensite transformation and consequently try to springback to their original shape after distortion. In contrast, the martensitic instruments have ability to reorientation of martensite variants when heated. So these instruments easily deformed and show a shape memory effect. Moreover, the use of martensitic alloy results in more flexible files, with an increased cyclic fatigue resistance compared with austenitic alloy. So, continued development in the manufacturing treatment of NiTi alloys has resulted in the producing of controlled memory (CM) wire. These materials do not possess superelastic properties at neither room nor body temperature. This article reviews the development process, features and properties of Hyflex file and Hyflex EDM file made from CM wire. Keywords: NiTi alloy, CM wire, Hyflex EDM, Heat treated NiTi

Screw-in force, torque generation, and performance of glide-path files with three rotation kinetics.

We aimed to evaluate the screw-in force, torque generation, and performance of three nickel-titanium (NiTi) glide-path files with different rotational kinetics. ProTaper Ultimate Slider (PULS) and HyFlex EDM Glide-path (HEDG) files were used for canal shaping with constant rotation (CON) or the alternative rotation technique (ART). In the ART mode, the NiTi file was periodically rotated at a speed of 1.5 times faster than that in the CON mode. WaveOne Gold Glider was used with reciprocating motion (WOGG_RCP). Sixty J-shaped resin blocks were assigned to five groups: PULS_CON, PULS_ART, HEDG_CON, HEDG_ART, and WOGG_RCP (n = 12). Glide-path preparation was performed using an automated pecking device. During glide-path preparation, the screw-in force and clockwise and counterclockwise torques were recorded and the number of pecking motions required to reach the working length was determined. The centering ratio was calculated after glide-path preparation using stereomicroscopic images. Data were analyzed using one-way analysis of variance with the Games-Howell post hoc test and the Kruskal-Wallis test with Bonferroni correction. PULS_ART generated a lower maximum screw-in force than PULS_CON. The average number of pecking motions required to reach the working length by HEDG_ART was lower than that by HEDG_CON. The mean centering ratios of PULS_CON and HEDG_CON were -0.04 and -0.06, respectively, while those of PULS_ART, HEDG_ART, and WOGG_RCP were 0.09, 0.01, and 0.08, respectively. The ART mode reduced the screw-in force of PULS and enabled faster glide-path preparation with the HEDG file.

Evaluation of Mechanical Versus Manual Root Canal Preparation in Primary Molars-A Comparative In Vitro Study.

The endodontic treatment of primary teeth is to maintain the function of the tooth free of symptoms until its physiological exfoliation. A critical factor for success is how quickly and effectively the root canal preparation can be performed. Therefore, the aim of this comparative in vitro study was to analyze the efficiency of two mechanical root canal preparation systems FM (FlexMaster) and HF (HyFlex EDM) to manual KF (K-file) on extracted primary molars. A total of 45 teeth were divided into three groups (n = 15): KF (#15-35), FM (04#30) and HF (25/~ OneFile). Root canal preparation was performed, and the preparation time was measured. All root canals were non-destructively analyzed by micro-computed tomography in the cervical, middle and apical thirds before and after preparation with regard to the parameters of canal transport (in μm) and centering ratio (0-1). Statistical analysis was performed at a 5% significance level using non-parametric tests. HF caused the lowest canal transport in the apical third (p = 0.008). The centering ratio value of HF was significantly higher in the middle third of the root canals than in the other two groups (p < 0.01). The mean instrumentation time was significantly higher for KF (6.67 min) than for FM (4.69 min) and HF (4.03 min, p < 0.01). HF can be recommended for primary molar root canal treatment.

In vitro evaluation of filling material removal and apical debris extrusion after retreatment using Reciproc blue, Hyflex EDM and ProTaper retreatment files

ObjectivesTo evaluate the amount of remaining filing material and apical debris extrusion after retreatment using Reciproc Blue, Hyflex EDM and ProTaper Retreatment Files.Materials and methodsThirty-six extracted permanent mandibular first molars with moderately curved mesial roots were selected. Mesiobuccal canals were prepared using the ProTaper Next system up to size X2 and filled using gutta-percha and Adseal sealer via cold lateral compaction. Teeth were randomly divided into three equal groups (n = 12): Group 1: Reciproc Blue (RB)(VDW, Germany), Group 2: Hyflex EDM (HEDM)(Coltene/Whaledent, Switzerland), Group 3: ProTaper Universal Retreatment file system + ProTaper Next file system (PTUR + PTN)( Dentsply Maillefer, Switzerland). Eppendorf tubes were used to collect the apically extruded debris. Cone-beam computed tomographic scans were taken prior to and after retreatment and the volume of remaining filling material was assessed at the coronal, middle and apical levels. Statistical analysis was performed using the Kruskal–Wallis test, Friedman's test and Wilcoxon Sign Rank test. Significance level was set at p value 0.05.ResultsThere were no statistically significant differences among the three groups in the reduction of the volume of the filling material or in the amount of apically extruded debris.ConclusionAll the tested filing systems showed similar efficacy in removing the filling material, however, none of them could achieve its complete removal. Apical extrusion of debris occurred with all the systems used with no significant difference between the three groups.

Enhancing debris removal in curved canals: a comparative evaluation of XP-endo Finisher and Passive Ultrasonic Irrigation.

The study aimed to compare the efficacy of XP-endo Finisher and Passive Ultrasonic Irrigation (PUI) in removing hard tissue debris from curved canals. Thirty-four mandibular molars with Vertucci's type II mesial canals were scanned in microcomputed tomography before and after preparation with HyFlex EDM, and accumulated hard tissue debris was quantified. Subsequently, the teeth were randomly divided into two groups according to the supplementary procedure: PUI with the Ultra-X insert or XP-endo Finisher. After the intervention, the specimens underwent another scanning. Two separate analyses were conducted, one for the total canal and another for the isthmus area. Unpaired and paired T-tests were used for inter- and intergroup comparisons, with a significance level set at 5%. Both supplementary methods reduced the amount of debris compared to the initial volume. Remarkably, the XP-endo Finisher achieved a significantly higher percentage of debris removal (71% for the total canal and 74% for the isthmus areas) compared to PUI (41% for the total canal and 52% for the isthmus area) (P < 0.05). Both supplementary approaches reduced the amount of hard tissue debris from canal preparation, still XP-endo Finisher showed a higher reduction compared to PUI (p < 0.05). None of the supplementary methods rendered canals completely free of hard tissue debris. However, the supplementary approach with XP-endo Finisher resulted in lower levels of hard tissue debris than PUI in curved canals with isthmuses.

Phase transformation and mechanical properties of heat-treated nickel-titanium rotary endodontic instruments at room and body temperatures

BackgroundThe aim of this study was to evaluate the phase composition, phase transformation temperatures, bending property, and cyclic fatigue resistance of different heat-treated nickel-titanium (NiTi) rotary instruments with the same tip diameter and taper at room (RT; 25 ± 1 °C) and body (BT; 37 ± 1 °C) temperatures.MethodsFive heat-treated NiTi rotary instruments, HyFlex EDM (EDM), HyFlex CM (CM), Vortex Blue (VB), RE file CT (RE) and JIZAI, and a non-heat-treated NiTi rotary instrument (Mtwo) with a size 40, 0.04 taper were investigated. Temperature-dependent phase transformation was examined with differential scanning calorimetry (DSC). The bending loads of the instruments at RT and BT were evaluated using a cantilever-bending test. Cyclic fatigue resistance at RT and BT was measured using a dynamic test, during which the instruments were rotated in combination with a 2-mm back-and-forth motion in an artificial curved canal, and the number of cycles to failure (NCF) was determined. The results were analyzed using two-way repeated measures analysis of variance, a simple main effect test, and the Bonferroni test (α = 0.05).ResultsDSC results indicated that EDM and Mtwo were primarily composed of martensite/R-phase and austenite, respectively, while the other heat-treated instruments were composed of a mix of martensite/R-phase and austenite at the tested temperatures. Regardless of the temperature setting, the bending loads of heat-treated instruments were significantly lower than those of Mtwo (p < 0.05). EDM showed the lowest bending loads and highest NCF at both temperatures (p < 0.05). CM, VB, and JIZAI showed significantly higher bending loads at BT than at RT (p < 0.05). The NCF of all the heat-treated instruments, except VB, was lower at BT than at RT (p < 0.05). At BT, the NCF of CM, VB, RE, and JIZAI were not significantly higher than that of Mtwo (p > 0.05).ConclusionsHeat-treated NiTi instruments exhibited lower bending loads and higher NCF values than Mtwo. However, this tendency was less pronounced at BT than at RT, especially in the NCF values of instruments with a mixture of martensite/R-phase and austenite phases at the tested temperatures.