scholarly journals Fatigue resistance of endodontic instruments manufactured in NiTi CM Wire and in conventional NiTi alloy with eletrochemical treatment

2018 ◽  
Vol 66 (2) ◽  
pp. 111-116
Author(s):  
Inês de Fátima de Azevedo Jacinto INOJOSA ◽  
Hélio Pereira LOPES ◽  
Phillip Lucas Ricardo PEREIRA ◽  
Diogo Lopes do NASCIMENTO ◽  
Carlos Nelson ELIAS ◽  
...  
Keyword(s):  
Cross Section ◽  
Fatigue Resistance ◽  
Manufacturing Process ◽  
Fracture Resistance ◽  
Niti Alloy ◽  
Fatigue Behavior ◽  
Morphological Characteristics ◽  
Static Fatigue ◽  
Number Of Cycles ◽  
Fractured Surface

ABSTRACT Objective: This study compared the fatigue behavior of endodontic instruments manufactured with conventional NiTi alloy electropolishing, RaCe (FKG Dentaire, LaChauxdeFonds, Switzerland), with instruments manufactured with NiTi CM Wire subjected to thermomechanical treatment, in the manufacturing process, HyFlex CM (Coltène Whaledent, Cuyahoga Falls, Ohio, USA), both with similar geometry and dimensions in order to determine the influence of the manufacturing process in the fatigue resistance. Methods: The methodoly consisted of twenty HyFlex CM and RaCe instruments with D0 0.25 mm, taper 0.06 mm / mm, 25 mm length, both with triangular cross section. The fracture resistance was evaluated by static fatigue test, using a stainless artificial canal with 5mm of radius (86°), recording the time and calculating the number of cycles until fracture occurs (NCF). For statistical analysis the Student t test was used The fractured instruments surface was analyzed by SEM. Results: The NCF was significantly higher for HyFlex CM instruments in comparison with RaCe files (P˂0.05) being 1336% more resistant to fatigue. The analysis of the fractured surface by SEM showed ductile-kind morphological characteristics for both instruments and the absence of plastic deformation. Conclusion: HyFlex CM instruments present higher values of NCF. Thus, it can be concluded that the thermal treatment to which these instruments with CM Wire alloy are submitted makes them more resistant to fracture than Race instruments manufactured with conventional NiTi alloy electropolishing.

scholarly journals Influence of the Geometrical Cross-Section Design on the Dynamic Cyclic Fatigue Resistance of NiTi Endodontic Rotary Files—An In Vitro Study

2021 ◽  
Vol 10 (20) ◽  
pp. 4713
Author(s):  
Vicente Faus-Llácer ◽  
Nirmine Hamoud-Kharrat ◽  
María Teresa Marhuenda Ramos ◽  
Ignacio Faus-Matoses ◽  
Álvaro Zubizarreta-Macho ◽  
...  
Keyword(s):  
Cross Section ◽  
Fatigue Resistance ◽  
Niti Alloy ◽  
Rectangular Cross Section ◽  
Study Groups ◽  
Cyclic Fatigue ◽  
Triangular Cross Section ◽  
Geometrical Cross Section ◽  
Section Design ◽  
Shaped Cross Section

The aim of this study was to analyze and compare the influence of the geometrical cross-section design on the dynamic cyclic fatigue resistance of NiTi endodontic rotary files. Materials and Methods: Forty sterile endodontic rotary files were selected and distributed into the following study groups: A: 25.06 double S-shaped cross-section NiTi alloy endodontic rotary files (Mtwo) (n = 10); B: 20.04 rectangular cross-section NiTi alloy endodontic rotary files (T Pro E1) (n = 10); C: 25.04 convex triangular cross-section NiTi alloy endodontic rotary files (T Pro E2) (n = 10); and D: 25.06 triangular cross-section NiTi alloy endodontic rotary files (T Pro E4) (n = 10). A cyclic fatigue device was used to conduct the static cyclic fatigue tests with stainless steel artificial root canal systems with 200 µm and 250 µm apical diameter, 60° curvature angle, 3 mm radius of curvature, 20 mm length, and 4% and 8% taper. The results were analyzed using the ANOVA test and Weibull statistical analysis. Results: All the pairwise comparisons presented statistically significant differences between the time to failure and number of cycles to failure for the cross-section design study groups (p < 0.001). Conclusions: the double S-shaped cross-section of Mtwo NiTi endodontic files shows higher cyclic fatigue resistance than the rectangular cross-section of T Pro E1 NiTi endodontic files, the convex triangular cross-section of T Pro E2 NiTi endodontic files, and the triangular cross-section of T Pro E4 NiTi endodontic files.

The mechanical behavior of poly(lactic acid) unreinforced and nanocomposite films subjected to monotonic and fatigue loading conditions

2011 ◽  
Vol 45 (26) ◽  
pp. 2717-2726 ◽  
Author(s):  
Rodney D. Averett ◽  
Mary L. Realff ◽  
Karl Jacob ◽  
Mukerrem Cakmak ◽  
Baris Yalcin
Keyword(s):  
Lactic Acid ◽  
Fatigue Resistance ◽  
Failure Time ◽  
Fatigue Behavior ◽  
Fatigue Loading ◽  
Nanocomposite Films ◽  
Poly Lactic Acid ◽  
Loading Conditions ◽  
Number Of Cycles ◽  
Cycles To Failure

The mechanical and fatigue behavior of neat poly(lactic acid) (PLA) films and PLA films reinforced with 5 wt% nanoclay particles has been examined using various analytical procedures. The results showed that for the films tested in this study, PLA-5 wt% samples were more susceptible to crazing at the same maximum fatigue stress as the neat PLA samples, as evidenced by results from light transmission experiments. Optical microscopy results confirmed this observation. In addition, under fatigue loading conditions, the neat PLA samples displayed almost the same fatigue resistance (number of cycles to failure) at 3 and 30 Hz, while the PLA-5 wt% samples showed a shift in the number of cycles to failure to higher values at a frequency of 30 Hz. Using the linear regression curves from the S– N data (stress vs. number of cycles to failure), time-to-failure curves were generated to show the difference between the neat PLA and PLA-5 wt% samples when tested at frequencies of 3 and 30 Hz. Based on these results, it is known that the nanoclay particles served to increase the fatigue resistance at the higher frequency of 30 Hz, when compared to the neat PLA sample.

scholarly journals Comparison of the resistance to cyclic fatigue of One Curve, One Shape, 2Shape and EdgeFile X3 files in simulated single and S-shaped (double) curvatures

2020 ◽  
Vol 10 (2) ◽  
pp. 55-59
Author(s):  
Mehmet Adıgüzel ◽  
Faruk Öztekin
Keyword(s):  
Statistical Analysis ◽  
Fatigue Resistance ◽  
Fracture Resistance ◽  
Native Speakers ◽  
Cyclic Fatigue ◽  
Nickel Titanium ◽  
Root Canals ◽  
Native Speakers Of English ◽  
Number Of Cycles ◽  
The One

Aim: To evaluate the fracture resistance to cyclic fatigue of One Curve (Micro-Mega, Besancon, Cedex, France), One Shape (Micro-Mega), 2Shape (Micro-Mega) and EdgeFile X3 (EdgeEndo, Albuquerque, NM) files in simulated root canals. Methodology: One hundred and sixty nickel-titanium endodontic files were tested in simulated canals with single and s-shaped (double) curvatures. The One Curve (25/.06), One Shape (25/.06), 2Shape (25/.06) and EdgeFile X3 (25/.06) files were assessed (n=20 for each test). All the files were rotated up to fracture occurred. The number of cycles to fracture (NCF) was determined and also, the length of the fractured file part was measured. For statistical analysis, one-way analysis of variance and Tukey HSD tests were used (p < 0.05).   Results: NCF for all instrument groups were significantly higher in the single curvature canal compared to the s-shaped curvature canal (p < 0.05). The EdgeFile X3 had the highest fatigue resistance in both curvature groups. The NCF of the One Curve were higher than that of the One Shape and 2Shape files (p < 0.05). In the s-shaped curvature canal, the files inclined to fracture more often in the apical curvature compared to the coronal curvature. There was no statistically considerable difference in the length of the fractured parts among the four experiment groups in either the single or s-shaped canal curvatures (p > 0.05). Conclusion: Within the limitations of this study, fracture resistance to cyclic fatigue was the highest for the EdgeFile X3 group followed by the One Curve group and lowest for the 2Shape and One Shape group.   How to cite this article: Adıgüzel M, Öztekin F. Comparison of the resistance to cyclic fatigue of One Curve, One Shape, 2Shape and EdgeFile X3 Files in simulated single and S-shaped (double) curvatures. Int Dent Res 2020;10(2):55-59. https://doi.org/10.5577/intdentres.2020.vol10.no2.5   Linguistic Revision: The English in this manuscript has been checked by at least two professional editors, both native speakers of English.

scholarly journals Influence of cross-section and number of use in cyclic fatigue resistance of rotary instruments

2019 ◽  
Vol 18 ◽  
pp. e191208
Author(s):  
Luís César Brisighello ◽  
George Táccio de Miranda Candeiro ◽  
Luiza Riomar Paz ◽  
Hermano Camelo Paiva ◽  
Giulio Gavini
Keyword(s):  
Cross Section ◽  
Fatigue Resistance ◽  
Significant Influence ◽  
Root Canal ◽  
Cyclic Fatigue ◽  
Curvature Radius ◽  
Rotary Instruments ◽  
The Cross ◽  
Number Of Cycles ◽  
Electric Engine

Aim: The aim of present study was to evaluate if the cross-section and the number of use have influence in cyclic fatigue resistance of rotary files. Methods: K3 Endo (group K) and EndoSequence (group E) files, 25/.04, 25 mm, were subdivided into 3 subgroups (n=12) according to the number of uses, 1, 3 and 5 uses, totalizing 72 files. The files were submitted to dynamic assays device moved by an electric engine, using 300 rpm of speed that permitted the reproduction of pecking motion. The files run within a temperate steel ring’s groove, simulating an instrumentation of a curved root canal with 40-degrees and 5-mm of curvature radius. The fracture of file was detected by sensor of device and the time and the number of cycles was acquired. The data were analyzed statistically by two-way ANOVA (p<0.05). Results: There were no statistical significant differences in regard to the number of uses (p>0.05). K3 Endo files showed greater resistance to cyclic fatigue than EndoSequence instruments (p<0.01). Conclusion: It may be concluded that the cross-section of instruments presented significant influence in cyclic fatigue resistance and the number of uses up to 5 times had no influence in cyclic fatigue resistance in both NiTi rotation systems evaluated.

scholarly journals Tension-Tension Fatigue Behavior of High-Toughness Zr61Ti2Cu25Al12 Bulk Metallic Glass

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2815
Author(s):  
Yu Hang Yang ◽  
Jun Yi ◽  
Na Yang ◽  
Wen Liang ◽  
Hao Ran Huang ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Shear Band ◽  
Metallic Glass ◽  
Bulk Metallic Glass ◽  
Fatigue Resistance ◽  
Metallic Glasses ◽  
Stress Amplitude ◽  
Fatigue Behavior ◽  
Bulk Metallic Glasses ◽  
High Toughness

Bulk metallic glasses have application potential in engineering structures due to their exceptional strength and fracture toughness. Their fatigue resistance is very important for the application as well. We report the tension-tension fatigue damage behavior of a Zr61Ti2Cu25Al12 bulk metallic glass, which has the highest fracture toughness among BMGs. The Zr61Ti2Cu25Al12 glass exhibits a tension-tension fatigue endurance limit of 195 MPa, which is higher than that of high-toughness steels. The fracture morphology of the specimens depends on the applied stress amplitude. We found flocks of shear bands, which were perpendicular to the loading direction, on the surface of the fatigue test specimens with stress amplitude higher than the fatigue limit of the glass. The fatigue cracking of the glass initiated from a shear band in a shear band flock. Our work demonstrated that the Zr61Ti2Cu25Al12 glass is a competitive structural material and shed light on improving the fatigue resistance of bulk metallic glasses.

scholarly journals Experimental Study of the Influence of the Surface Preparation on the Fatigue Behavior of Polyamide Single Lap Joints

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 1008
Author(s):  
Francesco Musiari ◽  
Fabrizio Moroni
Keyword(s):  
Experimental Study ◽  
Fatigue Behavior ◽  
Atmospheric Pressure Plasma ◽  
Surface Preparation ◽  
Lap Joints ◽  
Polymeric Surfaces ◽  
Adhesively Bonded Joints ◽  
Single Lap Joints ◽  
Number Of Cycles ◽  
Structural Adhesive

The low quality of adhesion performance on polymeric surfaces has forced the development of specific pretreatments able to toughen the interface between substrate and adhesive. Among these methods, atmospheric pressure plasma treatment (APPT) appears particularly suitable for its environmental compatibility and its effectiveness in altering the chemical state of the surface. In this work, an experimental study on adhesively bonded joints realized using polyamide as substrates and polyurethane as the structural adhesive was carried out with the intent to characterize their fatigue behavior, which represents a key issue of such joints during their working life. The single lap joint (SLJ) geometry was chosen and several surface pretreatments were compared with each other: degreasing, abrasion (alone and followed by APPT) and finally APPT. The results show that the abrasion combined with APPT presents the most promising behavior, which appears consistent with the higher percentage of life spent for crack propagation found by means of DIC on this class of joints with respect to the others. APPT alone confers a good fatigue resistance with respect to the simple abrasion, especially at a low number of cycles to failure.

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 2Shape, Twisted File and EndoSequence Xpress nickel-titanium rotary files at intracanal temperature

2018 ◽  
Vol 12 (4) ◽  
pp. 283-287 ◽  
Author(s):  
Gülşah Uslu ◽  
Taha Özyürek ◽  
Mustafa Gündoğar ◽  
Koray Yılmaz
Keyword(s):  
Fatigue Resistance ◽  
Statistical Significance ◽  
Cyclic Fatigue ◽  
Nickel Titanium ◽  
Bonferroni Correction ◽  
Significant Difference ◽  
Inner Diameter ◽  
The Difference ◽  
Number Of Cycles ◽  
Analyze Data

Background. The aim of this study was to compare the cyclic fatigue resistance of 2Shape, Twisted File (TF) and EndoSequence Xpress (ESX) nickel-titanium rotary files at intracanal temperature (35°C). Methods. Twenty 2Shape TS1 (25/.04), 20 TF (25/.04) and 20 ESX (25/.04) files were tested for cyclic fatigue at intracanal temperature (35°C). All the instruments were rotated in artificial canals which were made of stainless steel with an inner diameter of 1.5 mm, 60° angle of curvature and a radius curvature of 5 mm until fracture occurred; the time to fracture was recorded in seconds using a digital chronometer and the number of cycles to fracture (NCF) for each file was calculated. Kruskal-Wallis test with Bonferroni correction was performed to statistically analyze data using SPSS 21.0. Statistical significance was set at P<0.05. Results. NCF values revealed that the 2Shape had significantly the highest cyclic fatigue resistance, followed by TF and ESX at intracanal temperature (P<0.05). The difference was significant between the TF and ESX groups (P<0.05). There was no significant difference among the 2Shape, TF and ESX files with respect to the lengths of the fractured file fragments (P>.05). Conclusion. Within the limitations of present study, it was concluded that the cyclic fatigue resistance of 2Shape files at the intracanal temperature is higher than that of TF and ESX files.

Partial Devitrification of Sintered Silicon Nitride During Static Fatigue Testing

1992 ◽  
Vol 287 ◽  
Author(s):  
W. Braue ◽  
G. D. Quinn
Keyword(s):  
Fatigue Testing ◽  
Fatigue Behavior ◽  
Slow Crack Growth ◽  
Stress Rupture ◽  
Secondary Phase ◽  
Boundary Phase ◽  
Static Fatigue ◽  
Phase Assemblage ◽  
Transmission Electron ◽  
Stress States

ABSTRACTThe static fatigue behavior of sintered Y2O3/A12O3-fluxed Si3N4 in air is controlled by slow crack growth or creep fracture. Partial devitrification of the amorphous grain boundary phase at 1000°C and 1100°C improves the static fatigue resistance with specimens surviving up to 1500 hrs. during stress rupture experiments. In this study the early stages of partial devitrification during static fatigue testing at 1000°C are investigated by conventional and analytical transmission electron microscopy with emphasis on nucleation and growth of δ-Y2Si2O7 and X1-Y2SiO5 and possible constraints from different stress states. The results show that the stress state does not affect the nature of the secondary phase assemblage. However, the amount of crystallization is higher within the tensile region of the flexural specimens than in areas which experienced compressive stresses.

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