scholarly journals Cyclic Fatigue, Torsional Resistance, and Angular Deflection of Two Heat-Treated Files: M-Wire Versus New F-Wire Technology

Metals ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1359
Author(s):  
Ajinkya M. Pawar ◽  
Unmesh Khanvilkar ◽  
Shivani Mallishery ◽  
Kashmira Sawant ◽  
Ricardo Machado ◽  
...  
Keyword(s):  
Fatigue Testing ◽  
Cyclic Fatigue ◽  
Time To Failure ◽  
Significance Level ◽  
Root Canals ◽  
Angular Deflection ◽  
Torsional Resistance ◽  
Student’S T ◽  
Number Of Cycles ◽  
Angle Of Rotation

The cyclic fatigue, torsional resistance, and angular deflection of a new Fire-Wire rotary file (CricENDO) were compared. A total of 20 files of each type were tested. Cyclic fatigue testing was performed for each group (n = 10) by measuring the number of cycles to fracture (NCF) in an artificial stainless-steel canal (60° angle of curvature, with a 6-mm radius) for each group. The torque and angle of rotation at the failure of each group (n = 10) were measured according to ISO 3630-1. The fractured surfaces were examined using scanning electron microscopy. Statistical analysis was carried out utilizing Student’s t-test at a significance level set at 5%. The Fire-Wire CricENDO rotary files were associated with a significantly higher number of cycles to fracture and time to failure (in seconds) compared to the M-Wire Protaper Next (p < 0.05). A significantly higher angular deflection to fracture was observed for CricENDO compared to Protaper Next (p < 0.05). The new Fire-Wire CricENDO rotary files exhibit higher cyclic fatigue resistance and angle of rotation to fracture than M-Wire Protaper Next. Without warning, file fracture may occur as a result of cyclic fatigue, torsional stress, or a combined effect of both. CricENDO rotary files may be an effective alternative in curved root canals as they exhibited elevated cyclic and torsional resistance. It will be helpful in eliminating one of the reasons for file fracture during the root canal treatment.

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

2020 ◽  
Vol 14 (2) ◽  
pp. 111-115 ◽  
Author(s):  
Gülsah Uslu ◽  
Mustafa Gündoğar ◽  
Taha Özyürek ◽  
Gianluca Plotino
Keyword(s):  
Fatigue Resistance ◽  
Fatigue Testing ◽  
Cyclic Fatigue ◽  
Nickel Titanium ◽  
Clinical Environment ◽  
Root Canals ◽  
Rotary Instruments ◽  
Niti Instruments ◽  
Student’S T ◽  
Number Of Cycles

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 doublecurvedcanals in a simulated clinical environment. Methods. Eighty NiTi files were used for the fatigue testing in stainless steel canals compatible withinstrument 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 fileswere fractured due to cyclic fatigue, the fractured surfaces of the files were evaluated under a scanningelectron microscope. Data were statistically analyzed using the Kruskal–Wallis and Student’s t-tests atthe %95 confidence level. Results. The failure of the files due to cyclic fatigue was first seen in the apical curvature before thecoronal curvature (P<0.05). The highest fatigue resistance was observed in VDW.ROTATE and HyFlexCM files in both curvatures (P<0.05). There were no significant differences in the fatigue resistancebetween 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 coronalcurvatures (P>0.05). Conclusion. In artificial S-shaped root canals, VDW.ROTATE and HyFlex CM files exhibited higherfatigue resistance compared to 2Shape and TruNatomy files.

scholarly journals Shaping and Centering Ability, Cyclic Fatigue Resistance and Fractographic Analysis of Three Thermally Treated NiTi Endodontic Instrument Systems

Materials ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 5823
Author(s):  
Saulius Drukteinis ◽  
Vytaute Peciuliene ◽  
Ruta Bendinskaite ◽  
Vilma Brukiene ◽  
Rasmute Maneliene ◽  
...  
Keyword(s):  
Fatigue Resistance ◽  
Cyclic Fatigue ◽  
Fractographic Analysis ◽  
Significance Level ◽  
Root Canals ◽  
Topographic Features ◽  
New Instrument ◽  
Before And After ◽  
Number Of Cycles ◽  
Thermally Treated

The better understanding of the clinically important behavioral features of new instrument systems has an important significance for the clinical endodontics. This study aimed to investigate the shaping and centering ability as well as cyclic fatigue resistance of HyFlex CM (CM), HyFlex EDM (EDM) and EdgeFile (EF) thermally treated nickel–titanium (NiTi) endodontic instrument systems. Sixty curved root canals of the mesial roots of mandibular molars were randomly assigned into three groups (n = 20) and shaped using CM, EDM and EF files up to the size 40 and taper 04 of the instruments. µCT scanning of the specimens before and after preparation was performed and the morphometric 2D and 3D parameters were evaluated in the apical, middle and coronal thirds of root canals. In each group, 40.04 instruments (n = 20) were subjected to the cyclic fatigue resistance test in artificial root canals at 37 °C temperature until fractures occurred, and the number of cycles to failure (NCF) was calculated. The fractographic analysis was performed using a scanning electron microscope, evaluating topographic features and surface profiles of the separated instruments. The one-way analysis of variance with post hoc Tuckey’s test was used for statistical analysis of the data; the significance level was set at 5%. All systems prepared the comparable percentage of root canal surface with the similar magnitude of canal transportation in all root thirds (p > 0.05), but demonstrated significantly different resistance to cyclic fatigue (p < 0.05). The most resistant to fracture was EF, followed by EDM and CM. The length of the fractured fragments was not significantly different between the groups, and fractographic analysis by SEM detected the typical topographic features of separated thermally treated NiTi instrument surfaces.

scholarly journals Cyclic Fatigue Resistance of Rotary NiTi Instruments after Simulated Clinical Use in Curved Root Canals

2013 ◽  
Vol 24 (2) ◽  
pp. 117-120 ◽  
Author(s):  
Oscar Faciola Pessoa ◽  
Juliana Melo da Silva ◽  
Giulio Gavini
Keyword(s):  
Fatigue Resistance ◽  
Cyclic Fatigue ◽  
Nickel Titanium ◽  
Time To Failure ◽  
Clinical Use ◽  
Root Canals ◽  
Niti Instruments ◽  
Number Of Cycles ◽  
Curved Root Canals

The aim of this study was to assess cyclic fatigue resistance in rotary nickel-titanium instruments after simulated clinical use in curved root canals (40-degree, 5-mm radius curve). Thirty-six RaCe rotary NiTi files, size #5, taper 0.04, were divided into 3 groups: Groups A, B and C with one, three and five cycles of use, respectively. Time to failure was recorded with a stopwatch in seconds and subsequently converted to number of cycles to fracture. The data were analyzed statistically by ANOVA and Tukey's test (α=0.05). Five sets of clinically used files (group C) reached significantly lower cycle-numbers before fracture (mean=197.5 cycles) when compared with one set of clinically used files (mean=309.2) and three sets (mean=287.5). Results showed that the number of simulated clinical uses of RaCe instruments for shaping curved canals affects adversely the fatigue resistance of these instruments after five uses.

scholarly journals Cyclic Fatigue Resistance of Blue Heat-Treated Instruments at Different Temperatures

2021 ◽  
Vol 2021 ◽  
pp. 1-5
Author(s):  
Thalita Miranda Vieira ◽  
Ryhan Menezes Cardoso ◽  
Nayane Chagas Carvalho Alves ◽  
Silvio Emanuel Acioly Conrado de Menezes ◽  
Shirley Machado Batista ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Fatigue Resistance ◽  
Cyclic Fatigue ◽  
Significance Level ◽  
Instrument Type ◽  
Heat Treated ◽  
Different Temperatures ◽  
Vortex Blue ◽  
Student’S T ◽  
Student’S T Test

The main aim is to evaluate the cyclic fatigue resistance of blue heat-treated instruments with different kinematics. Twenty-four endodontic instruments of the same brand were used for each of three experimental groups: VB (Vortex Blue 40/0.04), RB (RECIPROC Blue 40/0.06), and XB (X1 Blue 40/0.06). The instruments were randomly distributed and subjected to temperatures of 20°C and 37°C. The fatigue test was performed using a stainless steel device. Data were analysed using the Shapiro–Wilk test, Student’s t-test, the F test, and Tukey’s and Tamhane tests at significance level P = 0.05 . The instruments’ cyclic fatigue resistance at both temperatures differed significantly for each instrument type ( P < 0.001 ). The RB instruments displayed greater cyclic fatigue resistance at the tested temperatures compared with the VB and XB instruments ( P < 0.001 ). Reciprocating kinematics positively influenced cyclic fatigue resistance. Blue heat-treated instruments showed decreased cyclic fatigue resistance as the temperature increased ( P < 0.001 ).

Combination of Cyclic Fatigue Testing and Materials Characterisation to Investigate Ageing of Elastomers

2017 ◽  
Vol 44 (4) ◽  
pp. 1-8 ◽  
Author(s):  
T. Kroth ◽  
D. Lellinger ◽  
I. Alig ◽  
M. Wallmichrath
Keyword(s):  
Fatigue Life ◽  
Molecular Mass ◽  
Fatigue Testing ◽  
Cyclic Fatigue ◽  
Chain Scission ◽  
Thermal Ageing ◽  
Fatigue Tests ◽  
Additive Package ◽  
Number Of Cycles ◽  
Cycles To Failure

Cyclic fatigue testing and elastomer characterisation were combined to study changes in material properties and network structure of elastomers during thermal ageing. Natural rubber containing a typical additive package with carbon black was studied as a model material. The samples were aged at different temperatures in air or under a nitrogen atmosphere. The fatigue life in number of cycles to failure (S-N curves) was determined from force- and displacement-controlled fatigue tests on tensile bar specimens after different thermal ageing times. Changes in mechanical properties and crosslink density were studied by tensile tests, dynamic mechanical analysis, stress relaxation experiments, compression set measurements, swelling measurements and solid-state NMR. Changes in network density during thermal ageing are related to the interplay between the formation of new crosslinks and chain scission. The average molecular mass of the network chains was found to be a suitable parameter for comparing different characterisation methods. An initial decrease in the molecular mass between two crosslinking points due to post-curing is followed by an increase due to chain scission. A similar trend was found for fatigue life in number of cycles to failure (N) in force-controlled fatigue tests: an increase in N for short ageing times is followed by a decrease after longer ageing times.

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

2020 ◽  
Vol 2020 ◽  
pp. 1-4
Author(s):  
Abdullah Mahmoud Riyahi ◽  
Amr Bashiri ◽  
Khalid Alshahrani ◽  
Saad Alshahrani ◽  
Hadi M. Alamri ◽  
...  
Keyword(s):  
Standard Deviation ◽  
Fatigue Resistance ◽  
Fatigue Testing ◽  
Clinical Performance ◽  
Cyclic Fatigue ◽  
Tooth Structure ◽  
Multiple Comparison Test ◽  
Continuous Rotation ◽  
Number Of Cycles ◽  
Cycles To Failure

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.

scholarly journals Fracture Resistance of K3 Nickel-Titanium Files Made from Different Thermal Treatments

2016 ◽  
Vol 2016 ◽  
pp. 1-6 ◽  
Author(s):  
JinWook Choi ◽  
Soram Oh ◽  
Yu-Chan Kim ◽  
Kwang-Koo Jee ◽  
KeeYeon Kum ◽  
...  
Keyword(s):  
Cyclic Fatigue ◽  
Nickel Titanium ◽  
Torsional Angle ◽  
Thermal Treatments ◽  
Heat Treated ◽  
Significant Difference ◽  
Number Of Cycles ◽  
Torsional Fracture ◽  
One Way Anova ◽  
Angle Of Rotation

The purpose of this study was to compare fracture resistances of K3 nickel-titanium files made from different thermal treatments. K3 (SybronEndo, Orange, CA), K3XF (SybronEndo), and experimentally heat treated K3 (K3H) were used. For the cyclic fatigue test, the samples were rotated with up-and-down motion in the artificial canal with the curvature of 60 degrees until the fracture occurred. The number of cycles to fracture (NCF) was measured. For the torsional fracture test, the samples were tightly bound and rotated until the fracture occurred. Elastic modulus (EM), ultimate torsional strength (UTS), and angle of rotation to fracture (ARF) were measured. The results were statistically analyzed by one-way ANOVA. The NCF of K3H was higher than those of K3 and K3XF (P<0.05). The EM of K3XF and K3H was lower than that of K3 (P<0.05). There was no significant difference in UTS. The ARF of K3XF was higher than that of K3 (P<0.05). K3XF and K3H showed more flexibility than K3. The maximum torsional angle of K3XF was higher than that of K3, but there was no significant difference on the UTS in all three groups.

scholarly journals Comparison of Cyclic Fatigue Resistance of Five Heat Treated NiTi Rotary Systems in Single and Double Curved Canals.

2021 ◽  
Author(s):  
Mohammad Al-Obaida ◽  
Khalid Merdad ◽  
Ali Alkhamis ◽  
Muneer Khan Mohammed ◽  
Rahaf Al-Obaida ◽  
...  
Keyword(s):  
Fatigue Resistance ◽  
Fatigue Testing ◽  
Cyclic Fatigue ◽  
Radius Of Curvature ◽  
Double Curvature ◽  
Heat Treated ◽  
Separation Pattern ◽  
Vortex Blue ◽  
Number Of Cycles ◽  
Post Hoc

Abstract BackgroundThe aim of this study was to compare cyclic fatigue resistance (CFR) and separation patterns during rotating movement of five heat-treated nickel titanium files in both single and double-curved canals. MethodsCFR was compared between five groups of 24 files each: HyFlex® EDM, HyFlex™ CM, Vortex Blue®, Protaper Next®, and One Curve, by determining the time needed to fracture (TTF) and the number of cycles to failure (NCF) in a cyclic fatigue testing device with a single 5-mm radius of curvature (ROC) and 60° angle, and a double curvature; coronal curvature (5 mm ROC and 60° angle) and apical curvature (2 mm ROC and 70° angle). The separation pattern was evaluated, and file fragment separated length were measured. One-way ANOVA and Tukey’s post-hoc were used to compare statistical differences between the groups. Scanning Electron Microscope (SEM) was used to investigate the fracture sites. Results HyFlex™ CM files displayed significantly higher CFR, followed by HyFlex® EDM and Vortex Blue® in single curvature canals, and Protaper Next® (PTN) in the double curvature canals, as observed by TFF and NCF. PTN group had the highest tendency for files to extrude apically after separation in both curvatures. ConclusionHyFlex™ CM instruments have superior resistance to cyclic flexural fatigue within single canals with single and double curvatures, followed by HyFlex® EDM and Vortex Blue® instruments. Protaper Next® files followed by One Curve had the highest tendency to extrude apically after separationClinical relevanceHyFlex™ CM instruments showed the highest safety in preparing canals with single or double curvatures, considering CFR.

scholarly journals Shaping Ability, Cyclic Fatigue Resistance and Fractographic Analysis of Hybrid and Reciprocating Nickel Titanium Endodontic Instruments

Metals ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 172 ◽  
Author(s):  
Saulius Drukteinis ◽  
Vytaute Peciuliene ◽  
Ruta Bendinskaite ◽  
Vilma Brukiene ◽  
Rasmute Maneliene ◽  
...  
Keyword(s):  
Fatigue Resistance ◽  
Root Canal ◽  
Cyclic Fatigue ◽  
Nickel Titanium ◽  
Significance Level ◽  
Root Canals ◽  
Working Length ◽  
Before And After ◽  
Canal Transportation ◽  
Shaping Ability

The aim of this study was to investigate the shaping ability and cyclic fatigue resistance of Genius (GN) and WaveOne (WO) nickel-titanium (NiTi) instruments. Forty mesial root canals of mandibular molars were randomly divided into two groups, according to the instrument system used for root canal preparation (n = 20): GN and WO. Root canals were prepared to the full working length using the crown-down technique, with up to 40.04 instruments for GN group and 40.08 instruments for WO group. Specimens were scanned with a µCT before and after instrumentation. The changes in 3D parameters and degree of canal transportation were evaluated in the apical, middle and coronal thirds of root canals. Size 25, taper 0.04 (GN) and 0.08 (WO) instruments (n = 20) were used in simulated root canals until fracturing, and the number of cycles to failure (NCF) was recorded. The fractured files were investigated under a scanning electron microscope to characterize fractured surfaces. Data were analyzed using ANOVA post hoc Tuckey’s tests with the significance level set at 5%. The GN system was able to prepare the higher percentage of the canal surface with less canal transportation in all root canal thirds and displayed the higher resistance to cyclic fatigue in comparison to WO instruments (p < 0.05). However, the length of the fractured segments was not significantly different among the groups; meanwhile, SEM investigations revealed the typical topographic characteristics of fractured surfaces. Hybrid GN instruments demonstrated superior shaping ability and resistance to cyclic fatigue. However, both NiTi instrument systems prepared the root canals with no significant shaping errors, considerable changes in 3D parameters and no significant differences in the topographic appearances of the instrument surfaces after fractures.

scholarly journals Need for Standardization: Influence of Artificial Canal Size on Cyclic Fatigue Tests of Endodontic Instruments

2021 ◽  
Vol 11 (11) ◽  
pp. 4950
Author(s):  
Sebastian Bürklein ◽  
Paul Maßmann ◽  
David Donnermeyer ◽  
Karsten Tegtmeyer ◽  
Edgar Schäfer
Keyword(s):  
Fatigue Testing ◽  
Cyclic Fatigue ◽  
Fatigue Tests ◽  
Nickel Titanium ◽  
Test Time ◽  
Root Canals ◽  
Melting Technique ◽  
Parallel Tube ◽  
Manufacturing Tolerances ◽  
Time To Fracture

The aim was to evaluate the influence of artificial canal size on the results of cyclic fatigue tests for endodontic instruments. Dynamic cyclic fatigue at body temperature using continuous tapered nickel–titanium F6-SkyTaper instruments (Komet, Lemgo, Germany), size 25/.06 with an amplitude of 3 mm, was tested in four different simulated root canals: (A) size of the instrument +0.02 mm (within the tolerances of the instruments); (B) +0.05 mm; (C) +0.10 mm; (D) parallel tube with 1.25 mm in diameter. The artificial canals (angle of curvature 60°, radius 5.0 mm, center of curvature 5.0 mm) were produced by a LASER-melting technique. Time and cycles to fracture, and lengths of the fractured instruments were recorded and statistically analyzed (Student–Newman–Keuls; Kruskal–Wallis test). Time to fracture significantly increased with increasing size of the artificial canals in the following order: A < B, C < D (p < 0.05). Length of separated instruments continuously decreased with increasing canal sizes. The parallel tube produced the significantly shortest fragments (p < 0.05). Within the limitations of this study, dynamic cyclic fatigue of endodontic instruments depends on the congruency of the instruments’ dimensions with that of the artificial canals. In future cyclic fatigue testing, due to the closer match of canal and instrument parameters, it is necessary to adjust the artificial canal sizes to the size of the instruments within the manufacturing tolerances of the instruments.

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