Twisted File Research Articles

Root Canal Transportation after Root Canal Preparation with ProTaper Next, WaveOne Gold, and Twisted Files.

Background: Root canal preparation during endodontic treatment may be associated with various complications, including a change in the original pathway of the root canal lumen. The aim of our study was to determine whether files of similar sizes that use various movement kinematics (rotary, reciprocal, adaptive motion) cause root canal transportation, and whether the differences between such systems are statistically significant. Methods: The degree of root canal transportation (DT) was calculated with the use of computed tomography scans for 3 groups of teeth (for each group: n = 20) in which the root canals were prepared using either rotary (ProTaper Next—PTN), reciprocal (WaveOne Gold—WOG), or adaptive movement (Twisted Files—TF) instruments. Results: For rotary ProTaper Next instruments, the mean value of the DT index was 0.0795 (SD = 0.0179) for 3 mm from the apex, 0.09 (SD = 0.0262) for 6 mm from the apex, and 0.106 (SD = 0.0221) for 9 mm from the apex. For reciprocal WaveOne Gold Primary instruments, the mean value of the DT index was 0.0355 (SD = 0.015) for 3 mm from the apex, 0.061 (SD = 0.02) for 6 mm from the apex, and 0.08 (SD = 0.25) for 9 mm from the apex. For Twisted Files, the mean value of the DT index was 0.05 (SD = 0.03) for 3 mm from the apex, 0.092 (SD = 0.17) for 6 mm from the apex, and 0.08 (SD = 0.02) for 9 mm from the apex. Conclusions: The use of PTN, WOG, and TF files resulted in root canal transportation to a different degree. The use of rotary PTN files produced the most transported preparation, whereas the use of WOG files produced the conservative root canal preparation that allowed the retention of the original shape of the root canal.

Effect of different kinematics and operational temperature on cyclic fatigue resistance of rotary NiTi systems

BackgroundThe aim of this study was to compare the effect of different kinematics and operational temperature on cyclic fatigue resistance of Protaper Next, WaveOne Gold, and Twisted File Adaptive files in a static model.MethodologyAn artificial canal, made of stainless steel with an inner diameter of 1.5 mm, a 60° angle of curvature, and a curvature radius of 2 mm, was used for the cyclic fatigue test immersed in a water bath for temperature adjustment (37 °C and 20 °C). A total of 120 files were divided into three groups according to the type of motion continuous rotation motion (CRM), adaptive motion (AM), and reciprocation motion (RM). Each group was further subdivided into two subgroups according to the operational temperature (37 °C and 20 °C), All instruments were operated until fracture occurred, and the time to fracture was recorded in seconds. Mean number of cycles to failure and standard deviations were calculated for each group, and data were analyzed statistically using two-way ANOVA followed by Tukey’s post hoc test (P ≤ 0.05).ResultsThe continuous rotation motion exhibited significantly lower cyclic fatigue resistance than reciprocating or adaptive motion (p ≤ 0.001) at 37 °C and 20 °C.ConclusionsCyclic fatigue resistance of NiTi files was affected by the motion used during root canal preparation. Reciprocation motion and adaptive motion resulted in extended fatigue. The operational temperature affects the cyclic fatigue resistance of the twisted file.

Evaluation of the effects of TF and S3 nickel-titanium instruments in severely curved molar root canal preparation

To compare the shaping ability and dental cracks of Twisted File and S3 in severely curved molar root canal preparation. Sixty extracted mandibular molars with mesiobuccal canals (canal curvature angles beyond 25°) were selected and divided randomly into 2 groups with 30 canals in each group. The canals were scanned by cone-beam CT(CBCT) before and after root canal preparation .The canal transportation was recorded at 3 points (3, 5, 7 mm to root tip). After root canal preparation，all the roots were horizontally sectioned 3，5 and 7mm from the apex. The slices were observed under optical stereomicroscope. SPSS 19.0 software package was used for statistical analysis. Transportations occurred in all groups. No significant difference was found between the two groups of canal transportation at the two points (5 mm and 7 mm to root tip) (P>0.05); at the point of 3 mm to the root tip,the transportation of canals prepared by S3 was obviously lesser than the canals prepared by TF. There was no significant difference in the incidence of dentinal cracks between the two groups (P>0.05). Under the conditions of severely curved molar root canal in extracted teeth, cracks were found in both groups, S3 was found to be better in maintaining original canal shape than TF system.

Ex-Vivo Comparison of Torsional Stress on Nickel-Titanium Instruments Activated by Continuous Rotation or Adaptive Motion.

This study aimed to evaluate the effect of adaptive motion applied to conventional nickel-titanium (NiTi) rotary instruments on torsional stress generation during shaping procedure. One hundred and twenty mesio-buccal canals of molars were randomly assigned to two groups according to the kinetics; adaptive motion (AD) and continuous rotation (CR). Each group was divided into four subgroups (n = 15) according to the NiTi instrument systems: HyFlex EDM, One Curve, Twisted File Adaptive, and ProTaper Next. A glide path was established with PathFile #1, for each file group being used with either of the kinetic movements. During the instrumentation with the designated motion and file system, the generated torque was measured via the control unit and acquisition module. Based on the acquired data, the maximum and total torque were calculated. The data were statistically analyzed using Kruskal–Wallis and Mann–Whitney tests at a significance level of 95%. The maximum and total torque generated by all instruments were significantly reduced by the adaptive motion (p < 0.05). In the CR group, HyFlex EDM generated the highest maximum and total stress. In the AD group, HyFlex EDM showed the highest maximum torsional stress, and One Curve showed the highest total torsional stress (p < 0.05). The TF Adaptive instrument with adaptive movement produced the lowest maximum and total torsional stress (p < 0.05). Under the conditions of this study, the use of adaptive motion would be useful to reduce the torsional stress of instrument and root dentin. The reduction of torsional stress through adaptive motion may enhance the durability of instruments and reduce the potential risk of dentinal cracks.

Lack of evidence of an important difference in postoperative pain when using Twisted File Adaptive or Reciproc systems for canal shaping during root canal treatment of posterior teeth

AlOmari T, AlThobiti G, AlThobaiti S, AlOufi F, Masuadi E, Jamleh A. Incidence of postoperative pain after canal shaping by using Reciproc and Twisted File Adaptive systems: a prospective, randomized clinical trial [published online ahead of print November 1, 2019]. Clin Oral Investig. https://doi.org/10.1007/s00784-019-03106-5.

Apical Debris Extrusion and Root Canal Cleanliness Using Several Rotary Nickel Titanium Files with Different Kinematics In Round and Oval Canals.

Aim: this study was conducted to evaluate and compare the amount of apically extruded debris and canal wall cleanliness using different Ni-Ti instruments (ProTaper file F2, Twisted File 25 and Reciproc R 25) used in continuous rotation and reciprocating motion, in round and oval root canals. Materials and methods: One hundred twenty extracted single rooted teeth were divided into two groups according to the cross section; 60 round and 60 oval cross section. Each group was subdivided into three subgroups according to the file system (20 ProTaper, 20 Twisted File and 20 Reciproc). Each subgroup was further divided into two divisions according to the motion used (10 rotation and 10 reciprocation). Teeth were mounted in glass vials through holes in the rubber stoppers. The glass vials were weighed before instrumentation. Root canal preparation was performed according to its assigned system according to the manufacturer's instructions, and distilled water was used as root canal irrigant. After instrumentation, the amount of apically extruded debris was evaluated by weighing the samples on the microbalance. Thereafter, roots were longitudinally divided for evaluation of smear layer by Scanning Electron Microscope SEM. The data were tabulated and subjected to statistical analysis. Results: Reciprocating motion extruded more debris than continuous rotation motion. SEM examination revealed greater amount of smear layer in the oval cross section canal than round cross section canal.

Cyclic Fatigue Comparison of TruNatomy, Twisted File, and ProTaper Next Rotary Systems.

TruNatomy (TN; Dentsply Sirona, Maillefer, Ballaigues, Switzerland) is a newly released system that was not tested in any previous studies. The objective of this work is to evaluate cyclic fatigue resistance of the new file and compare it with the Twisted Files (TF) and ProTaper Next (PTN). Forty-five files were distributed into 3 groups: PTN X2 (size 25 and taper 0.06), TF (size 25 and taper 0.06), and TN prime file (size 26 and taper 0.04). Each group included 15 files. Lengths of all files were 25 mm. Cyclic fatigue testing was done using artificial stainless-steel canals with 60-degree curvature and 5 mm radius. Continuous rotation movement at 300 rpm was used until the file fractures. Time for file separation was recorded in seconds. The number of cycles to failure (NCF) mean and standard deviation for each group was calculated. For statistical analysis of data, ANOVA and Tukey's multiple comparison test were used. Mean and standard deviation (SD) of NCF were 259 ± 37.2, 521.67 ± 63.07 and 846.67 ± 37.16 for PTN, TF, and TN respectively. TN on average had significantly the highest NCF compared with PTN (p < 0.05) and TF (p < 0.05). TruNatomy file showed superior cyclic fatigue resistance. With its potential to preserve tooth structure, this file offers a good cyclic fatigue advantage. However, future studies are required to evaluate other properties of this file and to examine its clinical performance.

Influence of glide path size and operating kinetics on time to reach working length and fracture resistance of Twisted File adaptive and Endostar E3 nickel-titanium file systems.

ObjectivesThis study investigated the influence of glide path size and operating kinetics on the time to reach the working length and the fracture resistance of Twisted File (TF) and Endostar E3 files.Materials and MethodsA total of 120 mandibular single-rooted premolars were selected. Two methods of kinetic motion (TF adaptive and continuous rotary motion) and file systems (TF and Endostar E3) were employed. The files were used in root canals prepared to apical glide path sizes of 15, 20, and 25. The time taken to reach the working length and the number of canals used before the instrument deformed or fractured were noted. Fractured instruments were examined with scanning electron microscopy.ResultsThe TF system took significantly more time to reach the working length than the Endostar E3 system. Both systems required significantly more time to reach the working length at the size 15 glide path than at sizes 20 and 25. A greater number of TFs than Endostar E3 files exhibited deformation, and a higher incidence of instrument deformation was observed in adaptive than in continuous rotary motion; more deformation was also observed with the size 15 glide path. One TF was fractured while undergoing adaptive motion.ConclusionsNo significant difference was observed between continuous rotary and adaptive motion. The TF system and adaptive motion were associated with a higher incidence of deformation and fracture. Apical glide path sizes of 20 and 25 required significantly less time to reach the working length than size 15.

Comparative evaluation of twisted and protaper files in pediatric endodontics – In-vitro study

Aim: The aim of the present in-vitro study was to evaluate the cutting efficiency of two nickel-titanium (NiTi) file systems, Twisted File (TF) and ProTaper file. Materials and Methods: Thirty extracted human primary tooth root canals were randomly divided into two groups with 15 root canals each. All the root canals after injected with Indian ink were instrumented with ProTaper Rotary NiTi files and Rotary NiTi TFs. All the root canals were then cleared to make them transparent. After the teeth appeared clear, they were observed under a stereomicroscope to check for residual Indian ink in the canals and scored. The data thus obtained were statistically analyzed with Chi-square test and Mann–Whitney test. Results: The mean of scoring of Group I, i.e., Rotary TF system, was 1.0. The mean of scoring of Group II, i.e., ProTaper Rotary file system, was 1.40. Conclusions: Root canal instrumentation of primary teeth showed nonsignificant differences in the cutting ability between the two systems of ProTaper and TF Rotary which were investigated, but signified a more even and uniform removal of dentin with the TF system.

Apical extrusion of root canal filling material during the removal of gutta-percha and resilon

Introduction. Root canal filling material may be extruded during retreatment through the apical foramen and cause flare-up or chronic infection. The aim of this study was to compare the apical extrusion of gutta-percha and resilon filling materials during retreatment using hand and rotary instruments. Methods. Sixty extracted single-rooted teeth with single, straight canal were selected. Canals were prepared with ProTaper Universal rotary system to a size F2. Two groups (30 teeth in each) were filled with gutta-percha or resilon points, respectively. In both groups teeth were randomly divided into the three subgroups (10 teeth in each), based on the instruments used for retreatment: Hedstrom hand files and two rotary groups- ProTaper and Twisted File instruments. Apical extrusion was detected visually, using a 4-degree scoring system. Mean scores were calculated and analyzed statistically (t-test and ANOVA). The level of significance was set at p &lt; 0.05. Results. Under tested experimental conditions, the type of canal filling material did not have significant effect on the results of apical extrusion during retreatment. Significantly more material was extruded in the resilon group when manual, Hedstrom file was used (1.80 ? 1.13) than rotary ProTaper (0.60 ? 0.70) and Twisted File (0.50 ? 0.71). Conclusions. The use of a rotary technique is recomended to minimize apical extrusion, especially when resilon obturation material is removed during retreatment.

Cleaning ability of rotary NiTi systems with different kinematics

BackgroundThe aim of this study was to compare the cleaning ability of rotary NiTi systems with different kinematics: ProTaper Next (PTN) (continuous rotation motion), WaveOne Gold (WOG) (reciprocating motion), and Twisted File Adaptive (TFA) (adaptive motion).MethodologySixty mesiobuccal roots from extracted mandibular molars were divided into three groups (n = 20): PTN, prepared by ProTaper Next; WOG, prepared by WaveOne Gold system; and TFA, prepared by Twisted File Adaptive systems. Teeth were longitudinally split into two halves for evaluation by scanning electron microscope. Images were analysed for debris and smear layer scores using the scoring system described by Hülsmann et al. (J Endod 23:301–6, 1997).ResultsNo significant difference was found between the three groups in the coronal one third (P = 0.071). However, the TFA group recorded a significantly higher percentage of debris in the middle and apical thirds (P < 0.001 and P < 0.001, respectively)ConclusionsUnder the conditions of this study, adaptive motion produced more debris than the reciprocating and the continuous rotating motions.

Incidence of postoperative pain after canal shaping by using Reciproc and Twisted File Adaptive systems: a prospective, randomized clinical trial.

The aim of this prospective clinical trial was to investigate the incidence of postoperative pain after initial root canal treatment using Twisted File Adaptive (TFA) and Reciproc systems. A total of sixty-four previously initiated or necrotic posterior teeth were randomly assigned to two groups based on the rotary system used; TFA (SybronEndo, Orange, Ca) (n = 35) and Reciproc (VDW, Munich, Germany) (n = 29). All teeth were treated in a single visit. Patients were contacted to assess the level of postoperative pain on a visual analog scale after treatment by 6 h, 24 h, 48 h, 72 h, and 1 week. Patients were also asked to report if any medication was taken during the follow-up period. The postoperative pain scores were analyzed by Mann-Whitney test with respect to follow-up interval at a significance level of 0.05. Patients treated with TFA reported significantly lower postoperative pain levels at 24 h, 48 h, and 72 h compared with those in Reciproc group (p < 0.01). There were no significant differences between the two groups at 6 h and 1-week follow-up intervals (p > 0.05). About 11% (TFA) and 24% (Reciproc) of the treated patients took analgesics, but none of them took antibiotics during the follow-up period. The tested rotary systems induced postoperative pain after root canal treatment. The TFA system was found to induce less pain scores compared with the Reciproc system after the treatment by 24 h, 48 h, and 72 h. The level of postoperative pain was low after the root canal treatment with the Twisted File Adaptive system compared with the Reciproc system.

Surface deformation of several nickel-titanium rotary instruments after removal of the root canal filling materials: a scanning electron microscope evaluation.

The aim of the present study was to investigate and compare the surface deformations of different NiTi rotary files after retreatment under scanning electron microscope (SEM). A total of 240 upper central incisor teeth were obturated with vertical compaction technique and divided into 6 groups. Root canals were retreated by ProTaper Next (PTN), Twisted File Adaptive (TFA), Reciproc (RPC), ProTaper Universal Retreatment (PTR), R-Endo and Mtwo-R NiTi rotary systems. The files investigated under SEM at different magnifications and photomicrographs were captured. The photomicrographs were classified and scored. Kruskal-Wallis and Dunn tests were performed for statistical analyze at 5% significance level. PTR and RPC groups were free of defects like file separation, curving and unwinding but PTN and TFA groups showed 50% file separation. According to the photomicrographs that were captured at high magnification; there were no statistically difference between groups at the coronal thirds of the files (P > 0.05), at the middle third PTN and TFA groups showed statistically more deformation than the other groups (P < 0.05). At the apical third Reciproc was statistically showed less deformation than the other all groups (P < 0.05). Within the limitation of this in vitro study, all NiTi files showed surface deformation in SEM observation after retreatment procedures. There was less deformation in PTR and RPC groups according to other.

Cyclic fatigue resistance of rotary NiTi instruments produced with four different manufacturing methods

The aim of this study was to compare the cyclic fatigue resistance of rotary NiTi files, produced with four different manufacturing methods on specially designed dynamic models that simulated clinical conditions. In this study, 120 files, consisting of 30 files for Typhoon, ProTaper Next, RaCe, and Twisted Files nickel titanium rotary systems were used. The 30 files of each group were divided into three subgroups to be used in artificial canals with a 60° angle of curvature and radii of curvature of 2, 5, and 8 mm (n = 10). All files were rotated in the artificial canals until fracture occurred and the number of cycles to fracture was calculated. The data were analyzed using one- and two-way analyses of variance and Tamhane multiple comparison tests. In all three groups, Typhoon instruments had the highest number of cycles to failure than the RaCe, ProTaper Next, and Twisted Files instruments, and the difference statistically significant (p < .05). There were no significant differences between the RaCe, ProTaper Next, and Twisted Files groups (p > .05). The CM wire Typhoon system was significantly more resistant to cyclic fatigue compared to the other file systems in all three artificial canals. When the fracture resistance of an instrument in three different artificial canals was compared, the mean NCFs decreased as the radius of the curvature of the canal decreased from 8 to 2 mm. Manufacturing method is one of the most important factors on cyclic fatigue resistance, also the radius of curvature effects the cyclic fatigue.

Effect of adaptive movement on durability and working time of twisted file

Effect of adaptive movement on durability and working time of twisted file

Comparison of In Vitro Torque Generation during Instrumentation with Adaptive Versus Continuous Movement

IntroductionThe purpose of this in vitro study was to compare the torque generated by continuous and adaptive movements of 2 nickel-titanium rotary file systems. MethodsForty-five simulated resin blocks with an S-shaped canal were randomly divided into 3 groups (n = 15) according to the file system and kinematics: the K3XF rotary system (Kerr Endodontics, Orange, CA) with continuous rotary movement, the K3XF with adaptive movement, and the Twisted File (Kerr Endodontics) adaptive file with adaptive movement. After creating a glide path, the canal was instrumented to the same size (.04/#20 for K3XF or SM1 for the Twisted File with adaptive movement) before torque measurement. During the final instrumentation procedure with the .06/25 sized file (K3XF or SM2), the generated torque and the preparation time were recorded. The total torque experienced and the maximum torque value were calculated. The data were statistically analyzed using 1-way analysis of variance and the Tukey post hoc comparison test at a significance level of 95%. ResultsThe K3XF file system used with adaptive motion group showed significantly lower total and maximum torque values compared with the K3XF with continuous rotary movement group. The Twisted File adaptive file with adaptive motion showed significantly lower torque generation and shorter preparation time than the K3XF groups with adaptive or continuous rotation (P < .05). ConclusionsUnder the conditions of this study, adaptive movement for nickel-titanium files may reduce torque generation without increasing preparation time. Nickel-titanium files with a smaller cross-sectional area using adaptive movement may be helpful to reduce the potential risk of root dentin damage.

Effect of Root Canal Geometry Versus Different Coronal Restorations on the Strength of Endodontically Treated Teeth

This study aimed to evaluate the combined effect of fiber post in different Root canal tapers. Sixty lower first premolar human extracted teeth had been used in this study, teeth were randomly divided into 3 equal groups (n=20). Group I; where cleaning and shaping was done using Twisted File (TF) #25 taper 0.04. Group II; where cleaning and shaping was done using Twisted File (TF) #25 taper 0.06. Group III; where cleaning and shaping was done using Twisted File (TF) #25 taper 0.08. Each main group was randomly subdivided into 2 equal subgroups (10 each) according to the coronal restoration type. Subgroup A; where coronal cavities were filled with Composite core material Multicore Flow (Ivoclar Vivadent, Schaan, Liechtenstein) (MCF), Subgroup B; where the coronal cavities were restored with fiber reinforced composite posts (FRC) and MCF. The fracture resistance of all groups had been evaluated & analyzed using Two-Way ANOVA. Results showed that 0.08 taper had a significant negative effect on the fracture resistance of teeth with and without post than 0.04 taper while other variants had no any statistically significant effect on the fracture resistance of the tested samples. It has been concluded that, under limitations of this study, the degree of taper of the root canal preparation only affects mechanical properties of the tooth when it increases more than 0.06 taper, while wether a post is used or not is of no use in class I conservative access cavity preparation of lower first premolar teeth.

Comparative Study of Cyclic Fatigue Resistance of Protaper Gold, OneShape, and TF Files

Aim: The purpose of this study was to compare the resistance to cyclic fatigue of three nickel-titanium (NiTi) endodontic instruments from Protaper Gold (PTG), OneShape (OS), and Twisted files (TF). Methodology: A total of 45 nickel-titanium instruments were tested and divided into 3 experimental groups (n = 15): group 1, Protaper Gold (F2 25/.08); group 2, OneShape (25/.06) file; and group 3, Twisted file (25/.06). The testing device was specially designed for this experiment. The time and cycles to failure were calculated. The data were compared for differences by using 2-way analysis of variance (p < 0.05). Results: Statistical analysis revealed that PTG showed the statistically significantly highest mean cyclic fatigue value, while TF showed statistically significantly lower mean cyclic fatigue value. OS system showed the statistically significantly lowest mean cyclic fatigue value. Conclusions: ProTaper Gold files demonstrated significantly higher cyclic fatigue resistance than OneShape and Twisted files, while OneShape files revealed the lowest cyclic fatigue resistance. The enhanced alloy properties of ProTaper Gold may be the main reason for this difference.

Durability of Two R-Phase Rotary Systems used in the Mechanical Instrumentation of Dilacerated Root Canals

This study was aimed to analyze, through an ex vivo test, the durability of two rotary systems used in curved root canals of extracted molars. At first, 150 upper and lower molars were selected, presenting curvature at least in one of the root canals. They underwent access cavity and radiographed with a # 15 file into the canal to determine their maximum curvatures, classified as schneider. The teeth with one or more curved canals were included in this study. Finally, 120 curved root canals were statistically divided into six sets of 20 curved canals. Two rotatory systems, K3 XF (RCS sequence) and twisted file (Large Kit), both treatment R-Phase, were analyzed. Three kits were used for each system, each one instrumented one of the six sets of 20 curved canals. File deformations were noted, and the files were used until a fracture occurs or until completion of 20 canals preparation. Fractured files before the end of the instrumentation of the 20 canals were replaced, continuing the full instrumentation set. Statistical analysis was performed by analysis of variance (ANOVA) (p >0.05), and a qualitative assessment was also made. It was found that there was no statistical difference between the K3 XF and TF systems regarding fracture. There were no statistical differences between the K3 XF systems in the RCS sequence and the twisted file kit Large system, as to the number of instrumented conduits to the deformation or fracture. The findings of this study reinforce that, it is necessary to choose files that support curved roots preventing accidents inside the root canal. Therefore, it is important for professionals to have knowledge and command of these protocols to obtain more satisfactory results.

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.