Fatigue failure of NiTi endodontic files: scoping review**

Falla por fatiga de limas NiTi para endodoncia: revisión exploratoria de cobertura temática

Yenny M. Orozco-Ocampo[1][*]

César A. Álvarez-Vargas[2]

Francy N Jiménez-García[3]

Daniel Escobar-Rincón[4]

Paola X. Jaramillo-Gil[5]

[1] MSc, Mechanics and Production Department, Universidad Autónoma de Manizales, Colombia. https://orcid.org/0000-0003-1907-6518

[2] PhDc, Mechanics and Production Department, Universidad Autónoma de Manizales, Colombia. https://orcid.org/0000-0002-4417-3865

[3] PhD, Physics and Mathematics Department, Universidad Autónoma de Manizales and Universidad Nacional de Colombia, Manizales, Colombia. https://orcid.org/0000-0003-1546-8426

[4] PhD, Physics and Mathematics Department, Universidad Autónoma de Manizales and Universidad Nacional de Colombia, Manizales, Colombia. https://orcid.org/0000-0003-4600-5117

[5] DDS, Oral Health Department, Universidad Autónoma de Manizales, Manizales, Colombia. https://orcid.org/0000-0001-5310-3626

Author notes:

Correspondence to: [*] CORRESPONDING AUTHOR: Yenny Marcela Orozco Ocampo yorozco@autonoma.edu.co

Conflicts of interest:

CONFLICT OF INTEREST The authors declare that they have no conflict of interest.

Date received: 21/2/2022

Date accepted: 03/5/2022

Abstract

Introduction:

Nickel-Titanium (NiTi) endodontic files are made of hyperelastic material with shape memory. However, these files suffer a sudden fracture during the endodontic treatment, which is considered an unfavorable prognosis. Many studies have been conducted to establish fatigue resistance focused on file brands and determine which is better. Although the most common failure mechanisms have been established for motorized endodontic files, the information is scattered, making it difficult to develop clear research trends.

Methods:

a scoping review was carried out using Scopus, Dimensions.ai, Web of Science, and Science Direct databases to answer screening questions related to the predominant fracture mechanism in NiTi files, test types, and equipment used for experimentation and to identify the most active authors.

Results:

using the general search terms, 432 research papers were found, of which 75 were finally selected after eliminating duplicates and applying exclusion criteria.

Conclusions:

typical failure mechanisms for rotatory and reciprocating files were identified based on the panoramic review and bibliometric indicators. Also, the standard mechanical tests for endodontic files and the characteristics of their assemblies were summarized. The most active authors in the area and their nationality were tagged. Finally, gaps for future research are proposed to generate a comprehensive knowledge of NiTi file failure.

Keywords:

nickel-titanium, endodontics, fatigue, scoping review

Resumen

Introducción:

las limas de Níquel-Titanio (NiTi) utilizadas en endodoncia están hechas de un material hiperelástico con memoria de forma. Sin embargo, estas limas sufren fractura repentina durante el tratamiento, lo cual se considera un pronóstico desfavorable. Se han realizado diversos estudios para establecer la resistencia a la fatiga de limas, y determinar cuál marca es mejor. Aunque se han establecido los mecanismos de falla más comunes para las limas de endodoncia motorizadas, la información se encuentra dispersa, dificultando la definición de tendencias claras de investigación.

Métodos:

se realizó una revisión de cobertura temática utilizando las bases de datos Scopus, Dimensions.ai, Web of Science y Science Direct, para responder a preguntas orientadoras relacionadas con el mecanismo de fractura predominante en las limas NiTi, tipos de pruebas y equipos utilizados para la experimentación e identificar los autores más activos en el área.

Resultados:

utilizando términos generales de búsqueda, se encontraron 435 trabajos de investigación. Finalmente se seleccionaron 75, tras eliminar duplicados y aplicar criterios de exclusión.

Conclusiones:

a partir de la revisión panorámica de literatura y empleando algunos indicadores bibliométricos, se identificaron los mecanismos de falla más comunes para las limas rotatorias y reciprocantes. Se obtuvo información sobre ensayos mecánicos y los montajes más utilizados para las limas de endodoncia. Se identificaron los autores más activos en el área y su nacionalidad. Por último, se sugieren oportunidades de investigación para generar un conocimiento exhaustivo sobre la falla de las limas NiTi.

Palabras clave:

níquel-titanio, endodoncia, fatiga, revisión de literature

INTRODUCTION

Fracture forms an integral part of fatigue cracking mechanisms in NiTi endodontic files. Due to the hyperelastic material behavior of NiTi, this alloy enables elastic deformations that are useful to follow the random geometry of the root canal1. However, these instruments are susceptible to fracture by fatigue2, which is considered harmful for the prognosis and treatment.3 A failure during the procedure implies a significant reduction in its effectiveness since the separated fragment can become an element that stands in the way of the successful eradication of the infection. In addition, this failure generates subsequent medical inconveniences if it is not possible its immediate removal.4

NiTi instruments are driven by an electric motor initially used with a continuous rotary motion. About ten years ago, the reciprocating motion (rotation changes direction at some point of the revolution) was introduced. From the beginning, studies have been conducted to minimize or eliminate the intrinsic defects of the material, increasing its hardness and flexibility, improving resistance to fatigue life, and prolonging its cutting efficiency.5 Fatigue failure resistance of NiTi files has been widely studied, mainly by comparing brands. However, few studies are related to completely understanding the fatigue failure mechanism1,6-9. Others are focused on the use of Finite Element Analysis10. Some experimental approaches have been developed to identify that the failure mechanism for rotatory files is flexural fatigue caused by the bending of the file when it is placed in the root canal. In this case, one of the file surfaces acts in tension, and the other works in compression.11

Figure 1 shows the primary failure process of the file when it is used inside the root canal. Tension and compression stresses occur when the file rotates inside the canals, causing fatigue failure (Figure 1A). Another mechanism is the torsional failure caused when a part of the NiTi instrument becomes trapped in the root canal (by friction and/or adhesion). At the same time, the driven motor continues rotating; this mechanism is illustrated in Figure 1B. A third failure mechanism known as the torsional fatigue can be identified for reciprocating instruments. In this case, the file is not trapped, but in the reciprocating motion, the friction between the root canal walls generates torsional opposition loads to the file, as shown in Figure 1C. The alternating direction of these friction forces causes fatigue failure. Stress vs. time behaviors is illustrated in Figure 1D.

There is a wide variety of cross-sectional geometries. NCF (number of cycles for fracture) values for NiTi rotary files have been recorded depending on this design12, demonstrating variability and randomness in fatigue failures due to the limited information collected during their operation. The biggest drawback is that the shape memory and superelasticity properties of the NiTi alloy imply that the files do not exhibit deformation or signs of the proximity of failure detectable with the human eye during endodontic treatment13,14. The operator does not perceive any deterioration until the file is fractured.

This scoping review focuses on identifying the different endodontic files studies related to fatigue behavior as well as gathering relevant information about the tests, types of studies, authors, and gaps in the area.

Figure 1

Failure mechanisms for NiTi endodontic files

0121-246X-rfoua-34-01-14-gf1.jpg

Source: by authors

METHODS

Research type

This document presents a scoping review of the available research articles coupled with bibliometric indicators such as co-occurrence and co-authorship citations. Bibliographic matching maps were generated to help the data visualization.

Search Strategy

For the panoramic exploration of the available research articles, the methodology is summarized in the following steps15,16:

  1. Search questions formulation.

  2. Search for publications (including search strings, databases selection, and inclusion and exclusion criteria).

  3. Data extraction and systematization.

  4. Information evaluation.

  5. Analysis and reports.

The following questions were formulated to guide the information search: What are the failure mechanisms identified for NiTi files? What tests are performed to determine the mechanical behavior of NiTi files, and what type of equipment is used? Who are the most active authors? How has the study of the failure of NiTi files evolved?

The following databases Scopus, Web of Science (WOS), Science Direct, and Dimensions. ai were reviewed to define which one provides more information and establish a general overview of the topics of interest. It was found that the answer to the question about the failure mechanism is summarized in the phenomenon of fatigue, which involves failure considerations related to torsional and bending loads. Therefore, the words “fatigue” (involving the most complex failure phenomenon) and “endodontic file” (object of study) were used to construct the search equation applied for filtering titles, abstracts, and keywords. Table 1 summarizes the search strings, databases, and the number of articles found in the review process. In this step of the review were found 412 research papers.

Table 1

Databases, search strings, and documents found for the initial stage of database review

Database Initial search equation # Docs
Scopus (TITLE-ABS-KEY (“endodontic file”) AND TITLE-ABS-KEY(fatigue)) 208
Dimensions.ai “endodontic file” AND “fatigue” 183
WOS TEMA: (“endodontic file”) AND TEMA: (fatigue) 25
Science Direct “endodontic file” AND “fatigue” 19

[i]Source: by authors

The search was refined using language inclusion criteria (documents in English, Spanish, Portuguese, and Italian), and as exclusion criteria, the areas of knowledge aerospace, chemistry, and earth unrelated to the subject of interest. This screening procedure results in 302 documents. The documents found in each database were compared to define duplications. A total of 154 documents were selected in this stage. Abstracts were reviewed to classify them according to the topic of interest and facilitate the filtering of documents. Finally, 75 papers were selected after discarding some that only discuss manufacturing techniques, thermal treatments, mechanical properties analysis (not including fatigue and torsion), and the alloy’s morphological characterization.

Since most of the documents were found in Scopus, it was established as the primary database for bibliometric indicators analysis. The documents obtained were exported using VOSviewer17. A thesaurus was built to unify terms. Co-occurrence, co-authorship, and bibliographic coupling maps were generated to identify the networks and answer the questions about the type of tests performed on NiTi endodontic files, authors associated with the area, and nationality, respectively.

RESULTS

For the co-occurrence map, the unit of analysis was the keywords. Figure 2 shows a density visualization graph of the network.

Figure 2

Density visualization. Co-occurrence analysis of the keywords in documents for review

0121-246X-rfoua-34-01-14-gf2.jpg

Source: by authors

The colors in the figure are related to the number of times that a keyword appears in the article set; the most repeated words are shown in red, in orange and yellow colors appear other less repeated terms related to the research topic. The graph confirmed that endodontic files made of NiTi are commonly subjected to fatigue, and torsion tests are generally made through the preparation of artificial canals.

For the construction of co-authorship networks, authors’ names were used as the unit of analysis the graph obtained with the software’s graphical tool shows seven clusters. However, only three of them were related, which means the presence of collaborative work. Authors such as Gambarini, Plotino, Testarelli, Grande, and Pedullá appeared with the highest number of published documents. Other clusters of authors were also identified, but the publications were not interrelated. The most active authors belong to the bigger cluster. However, in one of the smaller clusters, widely cited authors such as Freitas, Carvalho, and Lopes appeared. In another cluster appeared the author Shen, who was identified as relevant in early analyses of the entire databases.

To know about the evolution of the NiTi file fracture studies, the selected unit of analysis was authors and countries. The map established that in 2016 increased in United States, Brazil, and Italy the publication of papers related to fatigue failure tests for NiTi endodontic files. However, these days the tests are usually performed to establish resistance values (maximum values for failure) and used for brands comparison and sometimes to compare files from the same manufacturer.

Relevant information was extracted and allowed to establish the variables recorded in the tests such as time, the number of cycles to fracture-NCF, torque values, and the most common statistical analysis used for the experiments. Moreover, it gave a baseline for research parameters on endodontic file fatigue. This information is summarized in Figure 3.

Figure 3

Experimental design abstracted from the review

0121-246X-rfoua-34-01-14-gf3.jpg

Source: by authors

Similarly, from the documents that report experimental tests, it was possible to compile information regarding the experimental setups implemented and to characterize the endodontic files fatigue tests as follows:

  • Instrument operation can be with devices or with human operators.

  • The type of applied loads can be bending fatigue, torsional fatigue, or combined loads.

  • The materials used for artificial canals are steel, stainless steel, polymethyl methacrylate- PMMA, Polyester resin, 3D printing materials such as polylactic-acid-PLA, or acrylonitrile- butadiene-styrene-ABS, also glass.

  • Temperatures for the tests are room temperature or oral cavity temperature simulation.

  • For lubrication, researchers used deionized water, Hypochlorite solution, Glycerin or No- lubrication.

  • Most common inspection techniques: Optical microscopy, Scanning Electron Microscope-SEM, X-ray Diffraction-XRD, Transmission Electron Microscopy-TEM, Focused Ion Bema-FIB, Differential Scanning Calorimetry-DSC, and Micro Computed Tomography-MicroCT-scanning.

Table 2 summarizes the studies found in the scoping review. The scheme used to present data allows appreciating research evolution, associated authors, relevant findings, and observed variables.

Table 2

Summary of the fatigue failure on endodontic file research studies

Study findings Analyzed Variable(s) Authors Year
E: Cyclic axial motion significantly extends fatigue life. Fracture Time Dederich et al. 18 1986
C: Life cycle depends on the radius of curvature Fracture Time Haïkel et al. 19 1999
E: Analyze the type of defects after clinical use Fracture type Sattapan et al. 20 2000
C: Cutting edge design does not affect fatigue life, but the file size does. Fracture Time Chaves-Craveiro et al. 21 2002
I: Fatigue is the failure mechanism of Hedstrom files. Cracks Zinelis et al. 22 2002
E: The shape of root canals affects the life of the file. Flexibility Kuhn et al. 23 2002
E: Curved canals adversely affects torsional strength for Profile files. Angular speed and Torque Azevedo-Bahía et al. 24 2006
E: Evaluate the influence of curvature on fatigue life Arc length Pereira-Lopes et al. 25 2007
E: Heat treatment temperature influences fatigue strength Temperature and rotations Zinelis et al. 6 2007
E: Exposure to sodium hypochlorite does not affect fracture toughness. Torque, angle and NCF Ormiga et al. 26 2007
E: As angular deformation increases, fatigue cycles decrease. Torque, angle and NCF Ormiga et al. 27 2007
C: Material alloys ratio affects the fatigue life Angle of twist Johnson et al. 28 2008
E: Electropolishing does not affect the fatigue life of the files. Torque, angle and NCF Ormiga et al. 29 2008
E: Fracture patterns obtained by SEM can explain the fracture process. Torque, angle and NCF Ormiga et al. 7 2008
C: Files manufactured by twisting showed increased fatigue strength. Fracture Time Gambarini et al. 30 2008
L: Normative is required to standardize fatigue testing None Plotino et al. 11 2009
E: Fatigue is the main cause of file fracture over a static torsion Fracture type and rate Inan et al. 8 2009
E: Argon implantation improves performance of S1 files moderately. Number of cycles and crack Brilhante-Wolle et al. 31 2009
C: The process of manufacturing affects the fatigue strength of the file Angle of twist Park et al. 32 2010
E: Standard operation does not affect the self-adjusting file. Fracture Time Hof et al. 33 2010
C: M-wire exhibits higher fatigue strength than SE-Wire files Number of cycles Gao et al. 34 2010
C: Fracture is related to austenitic size grain Size and type of alloy grain Pirani et al. 9 2011
C: Twisting files show higher strength. Ductile fracture is observed. Fracture type and NCF Rodrigues et al. 35 2011
C: Reciprocating motion and twisting manufacturing improve strength. Fracture time Castelló-Escrivá et al. 36 2012
C: TF files have a higher fatigue resistance than GTX files. Number of cycles Miglio et al. 37 2012
S: Constitutive relationship for flexural fatigue Bending stresses Leroy et al. 38 2012
C: Manufacturing affects the fatigue life Number of cycles Bhagabati et al. 39 2012
E: Preflaring helps to increase fatigue life Number of cycles Ehrhardt et al. 40 2012
E: Geometry of canal affects fatigue life and fracture size Fracture length Al-Sudani et al. 41 2012
C: Manufacturing affects the fatigue life Number of cycles Bouska et al. (42) 2012
C: NiTi files have better mechanical fatigue behavior than steel Strength failure Pereira-Lopes et al. 43 2012
C: Compare brands to find the one with higher fatigue life Number of cycles Capar et al. 44 2013
C: Fracture length is an invariant Fracture length Plotino et al. 45 2014
E: Reciprocate motion affects the fatigue life Angular speed and torque Testarelli et al. 46 2014
E: Immersion in different irrigation solutions affects the fatigue life Time of immersion Pedullá et al. 47 2014
C: 15% torsional preload reduces the fatigue strength of EDM files Preload, torque, and angle Campbell et al. 48 2014
C: Mwire and CM treatments increase fatigue resistance of rotary files. Fracture time Braga et al. 49 2014
C: Compare brands to find the one with higher fatigue life Number of cycles Sousaa et al. 50 2015
C: Compare brands to find the one with higher fatigue life Number of cycles Capar et al. 51 2015
E: Preloads of torsion and fatigue are inversely proportional Number of cycles Shen et al. 52 2015
C: Preloads reduce the fatigue strength of files Preload, torque and angle Pedullá et al. 53 2015
E: Austenitic phase shows long fatigue life but reduced in R phase NCF, % elongation Freitas et al. 54 2015
C: Compare brands to find the one with higher fatigue life Number of cycles Özyürek et al. 55 2016
S: Stress intensity factors allow understanding the fatigue failure Stress intensity factor Isidoro et al. 56 2016
C: Compare brands to find the one with higher fatigue life Number of cycles Uslu et al. 57 2016
E: Large strains affect the fatigue life Number of cycles Chih-Wen et al. 58 2016
C: Compare new and used files to find the one with higher fatigue life Number of cycles Taha et al. 55 2016
E: Martensitic grain decreases the fatigue life Size and type of alloy grain Carvalho et al. 1 2016
E: The depth of the machining groove affects the NCF Fracture time Lopes et al. 59 2016
C: EDM, CMwire support lower torque but higher angle than Mwire Torque and angle Lo Savio et al. 60 2016
E: Back-forward motion extends fatigue life Fracture time Loios et al. 61 2016
C: Cyclic bending load reduces the torsional strength of CM files Torque and NCF Peláez-Acosta et al. 62 2016
E: The temperature of the environment influences the NCF Water temperature, NCF Dosanjh et al. 63 2017
C: Low environment temperature increases fatigue resistance Temperature, NCF Grande et al. 64 2017
E: Ti-Zr-B coating can improve fatigue resistance Fracture time Chih-Wen et al. 65 2017
E: Reduced apical depth generates less stress on the file Screw-in force Jung-Hong et al. 66 2017
E: Heat treatment increases fatigue resistance and cutting efficiency. Fracture time Chih-Wen et al. 67 2017
C: Compare brands to find the one with higher fatigue life Number of cycles Gundogar et al. 68 2017
C: Compare brands to find the one with higher fatigue life Number of cycles Azim et al. 69 2018
E: Relationship between the kinematics of file motor and fatigue life Number of cycles Iacono et al. 70 2018
E: Torsional preloads reduce fatigue strength of EDM files Preload, torque and angle Shen et al. 71 2018
E: Hypochlorite concentrations and temperature influence resistance Number of cycles Alfawaz et al. 72 2018
E: Fatigue life is affected by torque and curvature of the canal Torque and curvature Bhatta et al. 73 2019
C: Compare brands to find the one with higher fatigue life Number of cycles Jamleh et al. 74 2019
E: Microtomography allows non-destructive analysis of files Number of cycles Bastos et al. 75 2019
C: Compare new and used files to find the one with higher fatigue life Number of cycles Alvez et al. 3 2020
E: 2D-3D representations of canals show differences in stresses Number of cycles Piasecki et al. 76 2020
C: S-One files with higher resistance than M-Two, used in natural canals. Fracture time Miccoli et al. 77 2020
C: Fatigue resistance decreases at body temperature Fracture time Generali et al. 78 2020
C: All files are efficient in the preparation of the canal. Fracture time Drukteinis et al. 79 2020
C: ReFlex Smart file reciprocating motion increases fatigue resistance Fracture time Zubizarreta et al. 80 2021
C: Gold and Blue treatment improves resistance (bending and fatigue) Fracture time and load Xiao-Mei et al. 81 2021
E: Increasing apical and taper diameter reduces the dynamic fatigue strength Fracture time and pecks Faus-Llácer et al. 82 2021

[i]C: Comparison between brands; E: Experimental study on particular factors; L: Literature review; S: Simulations; I: Inspection Source: by authors

Regarding the information presented in Table 2, it can be established that most of the literature reviewed (47.9%) was focused on conducting comparative experiments (C) to determine which brand is more resistant to cyclic fatigue. Regarding the variables analyzed, the time for file fracture in continuous operation is generally measured (23.3%)65,77, and the number of cycles to fracture or NCF was determined (53.4%)21,62. Those results provide information about the research trends in endodontic files failure and show possibilities for future studies not centered on comparison only.

DISCUSSION

From the information presented in Table 2, it is established that most of the literature reviewed (47.9%) is focused on conducting comparative experiments (C) to determine which brand is more resistant to cyclic fatigue. Regarding the variables analyzed, the time for file fracture in continuous operation is generally measured (23.3%)65,77, and the number of cycles to fracture or NCF was determined (53.4%)21,62. Those results provide information about the research trends in endodontic files failure and show possibilities for future studies not centered on comparison only.

Flexural fatigue tests are generally performed by allowing free rotation of the file within the canals. However, some documents discuss other types of tests applied to files, one of them is related with torsional loads in which the file´s tip is fixed with resin or bronze jaws64,73. It should be noted that most of the studies were in-vitro, and only two were previously in human patients. After the endodontic treatment, the files were subjected to fatigue tests in artificial canals40,79. Most of the experiments were performed with artificial canals made of metal plates, resin, and other materials (30.1%)20,68, which severely affected the file's fatigue life. Also, two studies were developed simulating body temperature72,78. These studies allowed the establishment of the actual methods used for experimentation and show the need to approach the research to simulate oral cavity conditions.

Experimental tests for NiTi files can be classified as static in the case of keeping a constant file’s length inside the artificial canal; and dynamic in the case of operating with axial motions inside and outside the canal, which is known as pecking motion. This movement contributes to extended fatigue life, which is reduced by the complex geometry of the root canals32,80. Fracture occurs in the middle of the bending radius in experimental tests that involve static fatigue loads38,41. These results contribute to determining the fracture's length and can be considered a basis for future studies that focus on understanding failure.

Immersion in substances such as sodium hypochlorite does not affect fatigue resistance. However, immersion in ethylenediaminetetraacetic-acid-EDTA for more than three minutes considerably affects fatigue resistance. In addition, the effect of different percentages of sodium hypochlorite concentrations have been studied and are defined to be used between 2.5% - 5.0%47.

Some files show differences in fatigue resistance depending on the motor with which they are operated. However, Wave One® files do not significantly differ when working with X-Smart or EVO motors46. Inherent file factors such as cross-sectional geometry, number of spirals in the working section, coating, and manufacturing method influence fatigue, torsional, and bending strength. Finally, the files manufactured by twisting have higher resistance values than those manufactured by grinding35.

In all the experimental tests, a preliminary inspection was made to verify that the file’s surface was free of imperfections that may affect the results. When the file is broken, SEM analysis is the most common technique to inspect the fractured sections19,57,82. Small austenitic grains are observed near the tip after the operation and fracture of the file9.

Many tools are used for the experiment's statistical analysis as shown by Bonferroni45, Weibull and Levene69. However, those methods related to the comparison of the population tend to prevail25,83, according to the trend to make comparative studies between files references and brands.

Regarding publications, the diffusion of knowledge about the failure of endodontic files manufactured with NiTi alloy started in 1986. Publications increased around 2012, and 2019 was one of the most productive years, reinforcing the relevance of this topic and the need to continue researching NiTi endodontic file failure comprehension.

Due to the operating conditions of the NiTi files (most like dynamic fatigue test) and values identified for fracture failure, the fatigue can be classified as low cycling. So, it is necessary to develop the strain-life curves and crack propagation models. Because most tests are performed in artificial canals made of different materials, which differ from dentin behavior, it is necessary to generate knowledge related to the friction and adhesion generated between the file and the canal material. Additionally, it is required to establish the differences in performance of the same NiTi file in canals made of different materials.

Concerning the operation of the files, it is required to use equipment and assemblies that ensure the repeatability of the experiment and eliminate errors introduced by a human operator. Finally, very few studies attempt to understand the instrument's fracture mechanics and therefore do not delve into the phenomenology of the failure process. And, there are no proposals for failure proximity detection methodologies.

CONCLUSIONS

Scopus contains the most significant number of documents and includes the majority of the articles present in other databases. Also, it was verified that the Dimensions.ai open-access database contains more than 80% of Scopus articles, positioning this database as a relevant information source.

It was found that most studies have focused on comparative experimentation between references and brands but do not delve into the understanding of the failure phenomenon that would allow predicting it.

The predominant failure mechanism for NiTi endodontic files was identified as cyclic fatigue caused by bending or torsion. Besides, most tests are static and are conducted for rotational motion of the files more than for reciprocanting movement. It is relevant to quote that reciprocanting motion of files involves a more severe regime of cyclic fatigue.

It was noted that there are no standardized tests for the development of cyclic fatigue experimentation. Each author conducts tests using different measurement parameters and methods. Therefore, it is necessary to work on the standardization of the tests to unify the failure criteria.

ACKNOWLEDGMENTS

The authors gratefully acknowledge the Ministry of Science, Technology and Innovation (MinCiencias) of the Republic of Colombia for their financial support (Grant Code: 80740- 176-2020) through the Research Office of the Universidad Autónoma de Manizales (Project number 698-106).

REFERENCES

1. Carvalho A, Freitas M, Reis L, Montalvão D, Fonte M. Rotary fatigue testing to determine the fatigue life of NiTi alloy wires: an experimental and numerical analisys. Procedia Struct Integr. 2016; 1: 34-41. DOI: https://doi.org/10.1016/j.prostr.2016.02.006

A Carvalho M Freitas L Reis D Montalvão M Fonte Rotary fatigue testing to determine the fatigue life of NiTi alloy wires: an experimental and numerical analisysProcedia Struct Integr.201613441https://doi.org/10.1016/j.prostr.2016.02.006

2. Marques Ferreira M, Rebelo D, Caramelo F, Carrilho E, Loureiro M. In vitro evaluation of wear and canal transportation using reciprocating instruments: RECIPROC® vs WaveOne® files. Rev Port Estomatol Med Dent e Cir Maxilofac. 2013; 54(3): 117-23. DOI: https://doi.org/10.1016/j.rpemd.2013.04.001

M Marques Ferreira D Rebelo F Caramelo E Carrilho M Loureiro In vitro evaluation of wear and canal transportation using reciprocating instruments: RECIPROC® vs WaveOne® filesRev Port Estomatol Med Dent e Cir Maxilofac.2013543117123https://doi.org/10.1016/j.rpemd.2013.04.001

3. Duque JA, Bramante CM, Duarte MAH, Alcalde MP, Silva EJNL, Vivan RR. Cyclic fatigue resistance of Nickel-Titanium reciprocating instruments after simulated clinical use. J Endod. 2020; 46(11): 1771-5. DOI: https://doi.org/10.1016/j.joen.2020.08.010

JA Duque CM Bramante MAH Duarte MP Alcalde EJNL Silva RR Vivan Cyclic fatigue resistance of Nickel-Titanium reciprocating instruments after simulated clinical useJ Endod.2020461117711775https://doi.org/10.1016/j.joen.2020.08.010

4. Sjogren U, Hagglund B, Sundqvist G, Wing K. Factors affecting the long-term results of endodontic treatment. J Endod. 1990; 16(10): 498-504. DOI: https://doi.org/10.1016/s0099-2399(07)80180-4

U Sjogren B Hagglund G Sundqvist K Wing Factors affecting the long-term results of endodontic treatmentJ Endod.19901610498504https://doi.org/10.1016/s0099-2399(07)80180-4

5. Mohammadi Z, Soltani MK, Shalavi S, Asgary S. A review of the various surface treatments of NiTi instruments. Iran Endod J. 2014; 9(4): 235-40.

Z Mohammadi MK Soltani S Shalavi S Asgary A review of the various surface treatments of NiTi instrumentsIran Endod J.201494235240

6. Zinelis S, Darabara M, Takase T, Ogane K, Papadimitriou GD. The effect of thermal treatment on the resistance of nickel-titanium rotary files in cyclic fatigue. Oral Surgery Oral Med Oral Pathol Oral Radiol Endodontology. 2007; 103(6): 843 DOI: https://doi.org/10.1016/j.tripleo.2006.12.026

S Zinelis M Darabara T Takase K Ogane GD Papadimitriou The effect of thermal treatment on the resistance of nickel-titanium rotary files in cyclic fatigueOral Surgery Oral Med Oral Pathol Oral Radiol Endodontology20071036843843https://doi.org/10.1016/j.tripleo.2006.12.026

7. Barbosa FOG, Ponciano Gomes JAdaC, de Araújo MCP. Fractographic analysis of K3 nickel-titanium rotary instruments submitted to different modes of mechanical loading. J Endod. 2008; 34(8): 994-8. DOI: https://doi.org/10.1016/j.joen.2008.05.013

FOG Barbosa JAdaC Ponciano Gomes MCP de Araújo Fractographic analysis of K3 nickel-titanium rotary instruments submitted to different modes of mechanical loadingJ Endod.2008348994998https://doi.org/10.1016/j.joen.2008.05.013

8. Inan U, Gonulol N. Deformation and fracture of Mtwo Rotary Nickel-Titanium instruments after clinical use. J Endod. 2009; 35(10): 1396-9. DOI: https://doi.org/10.1016/j.joen.2009.06.014

U Inan N Gonulol Deformation and fracture of Mtwo Rotary Nickel-Titanium instruments after clinical useJ Endod.2009351013961399https://doi.org/10.1016/j.joen.2009.06.014

9. Pirani C, Cirulli PP, Chersoni S, Micele L, Ruggeri O, Prati C. Cyclic fatigue testing and metallographic analysis of nickel-titanium rotary instruments. J Endod. 2011; 37(7): 1013-6. DOI: https://doi.org/10.1016/j. joen.2011.04.009

C Pirani PP Cirulli S Chersoni L Micele O Ruggeri C Prati Cyclic fatigue testing and metallographic analysis of nickel-titanium rotary instrumentsJ Endod.201137710131016https://doi.org/10.1016/j. joen.2011.04.009

10. Legrand V, Moyne S, Pino L, Chirani SA, Calloch S, Chevalier V, et al. Mechanical behavior of a NiTi endodontic file during insertion in an anatomic root canal using numerical simulations. J Mater Eng Perform. 2015; 24(12): 4941-7. DOI: http://dx.doi.org/10.1007/s11665-015-1799-0

V Legrand S Moyne L Pino SA Chirani S Calloch V Chevalier Mechanical behavior of a NiTi endodontic file during insertion in an anatomic root canal using numerical simulationsJ Mater Eng Perform.2015241249414947http://dx.doi.org/10.1007/s11665-015-1799-0

11. Plotino G, Grande NM, Cordaro M, Testarelli L, Gambarini G. A review of cyclic fatigue testing of Nickel-Titanium rotary instruments. J Endod. 2009; 35(11): 1469-76. DOI: https://doi.org/10.1016/j.joen.2009.06.015

G Plotino NM Grande M Cordaro L Testarelli G Gambarini A review of cyclic fatigue testing of Nickel-Titanium rotary instrumentsJ Endod.2009351114691476https://doi.org/10.1016/j.joen.2009.06.015

12. Cheung GSP. Instrument fracture: mechanisms, removal of fragments, and clinical outcomes. Endod Top. 2009; 16(1): 1-26. DOI: https://doi.org/10.1111/j.1601-1546.2009.00239.x

Cheung GSP Instrument fracture: mechanisms, removal of fragments, and clinical outcomesEndod Top.2009161126https://doi.org/10.1111/j.1601-1546.2009.00239.x

13. Ashrafi MJ, Arghavani J, Naghdabadi R, Auricchio F. A three-dimensional phenomenological constitutive model for porous shape memory alloys including plasticity effects. J Intell Mater Syst Struct. 2015; 27(5): 608-24. DOI: https://doi.org/10.1177%2F1045389X15575085

MJ Ashrafi J Arghavani R Naghdabadi F Auricchio A three-dimensional phenomenological constitutive model for porous shape memory alloys including plasticity effectsJ Intell Mater Syst Struct.2015275608624https://doi.org/10.1177%2F1045389X15575085

14. Karamooz-Ravari MR, Dehghani R. The effects of shape memory alloys’ tension-compression asymmetryon NiTi endodontic files’ fatigue life. Proc Inst Mech Eng Part H J Eng Med. 2018; 232(5): 437-45. DOI: https://doi.org/10.1177/0954411918762020

MR Karamooz-Ravari R Dehghani The effects of shape memory alloys’ tension-compression asymmetryon NiTi endodontic files’ fatigue lifeProc Inst Mech Eng Part H J Eng Med.20182325437445https://doi.org/10.1177/0954411918762020

15. Munn Z, Peters MDJ, Stern C, Tufanaru C, McArthur A, Aromataris E. Systematic review or scoping review? Guidance for authors when choosing between a systematic or scoping review approach. BMC Med Res Methodol. 2018; 18.

Z Munn MDJ Peters C Stern C Tufanaru A McArthur E Aromataris Systematic review or scoping review? Guidance for authors when choosing between a systematic or scoping review approachBMC Med Res Methodol.201818

16. Sucharew M, Macaluso M. Methods for research evidence synthesis: the scoping review approach. J Hosp Med. 2019; 14(7): 416-8. DOI: https://doi.org/10.12788/jhm.3248

M Sucharew M Macaluso Methods for research evidence synthesis: the scoping review approachJ Hosp Med.2019147416418https://doi.org/10.12788/jhm.3248

17. Waltman L, Jan van Eck N. Citation-based clustering of publications using CitNetExplorer and VOSviewer. Scientometrics. 2017; 111. DOI: https://doi.org/10.1007/s11192-017-2300-7

L Waltman N Jan van Eck Citation-based clustering of publications using CitNetExplorer and VOSviewerScientometrics2017111https://doi.org/10.1007/s11192-017-2300-7

18. Dederich DN, ZAkariasen KL. The effects of cyclical axial motion on rotary endodontic instrument fatigue. Oral Surg Oral Med Oral Pathol. 1986; 61(2): 192-6. DOI: https://doi.org/10.1016/0030-4220(86)90186-6

DN Dederich KL ZAkariasen The effects of cyclical axial motion on rotary endodontic instrument fatigueOral Surg Oral Med Oral Pathol.1986612192196https://doi.org/10.1016/0030-4220(86)90186-6

19. Haïkel Y, Serfaty R, Bateman G, Senger B, Allemann C. Dynamic and cyclic fatigue of engine-driven rotary Nickel-Titanium endodontic instruments. J Endod. 1999; 25(6): 434-40. DOI: https://doi.org/10.1016/s0099-2399(99)80274-x

Y Haïkel R Serfaty G Bateman B Senger C Allemann Dynamic and cyclic fatigue of engine-driven rotary Nickel-Titanium endodontic instrumentsJ Endod.1999256434440https://doi.org/10.1016/s0099-2399(99)80274-x

20. Sattapan B, Nervo GJ, Palamara JE, Messer HH. Defects in rotary nickel-titanium files after clinical use. J Endod. 2000; 26(3): 161-5. DOI: https://doi.org/10.1097/00004770-200003000-00008

B Sattapan GJ Nervo JE Palamara HH Messer Defects in rotary nickel-titanium files after clinical useJ Endod.2000263161165https://doi.org/10.1097/00004770-200003000-00008

21. Craveiro De Melo MC, De Azevedo Bahia MG, Buono VTL. Fatigue resistance of engine-driven rotary nickel- titanium endodontic instruments. J Endod. 2002; 28(11): 765-9. DOI: https://doi.org/10.1097/00004770-200211000-00005

MC Craveiro De Melo MG De Azevedo Bahia VTL Buono Fatigue resistance of engine-driven rotary nickel- titanium endodontic instrumentsJ Endod.20022811765769https://doi.org/10.1097/00004770-200211000-00005

22. Zinelis S, Margelos J. Failure mechanism of hedstroem endodontic files in vivo. J Endod. 2002; 28(6): 471- 3. DOI: https://doi.org/10.1097/00004770-200206000-00014

S Zinelis J Margelos Failure mechanism of hedstroem endodontic files in vivoJ Endod.20022864714 3https://doi.org/10.1097/00004770-200206000-00014

23. Kuhn G, Jordan L. Fatigue and mechanical properties of nickel-titanium endodontic instruments. J Endod. 2002; 28(10): 716-20. DOI: https://doi.org/10.1097/00004770-200210000-00009

G Kuhn L Jordan Fatigue and mechanical properties of nickel-titanium endodontic instrumentsJ Endod.20022810716720https://doi.org/10.1097/00004770-200210000-00009

24. Bahia MGA, Melo MCC, Buono VTL. Influence of simulated clinical use on the torsional behavior of nickel- titanium rotary endodontic instruments. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2006; 101(5): 675-80. DOI: https://doi.org/10.1016/j.tripleo.2005.04.019

MGA Bahia MCC Melo VTL Buono Influence of simulated clinical use on the torsional behavior of nickel- titanium rotary endodontic instrumentsOral Surg Oral Med Oral Pathol Oral Radiol Endod.20061015675680https://doi.org/10.1016/j.tripleo.2005.04.019

25. Lopes HP, Moreira EJL, Nelson Elias C, Andriola de Almeida R, Neves MS. Cyclic fatigue of protaper instruments. J Endod. 2007; 33(1): 55-7. DOI: https://doi.org/10.1016/j.joen.2006.09.003

HP Lopes EJL Moreira C Nelson Elias R Andriola de Almeida MS Neves Cyclic fatigue of protaper instrumentsJ Endod.20073315557https://doi.org/10.1016/j.joen.2006.09.003

26. Barbosa FOG, Gomes JACP, de Araujo MCP. Influence of sodium hypochlorite on mechanical properties of K3 Nickel-Titanium rotary instruments. Journal of endodontics 2007; 33(8): 982-5. DOI: https://doi.org/10.1016/j. joen.2007.05.008

FOG Barbosa JACP Gomes MCP de Araujo Influence of sodium hypochlorite on mechanical properties of K3 Nickel-Titanium rotary instrumentsJournal of endodontics2007338982985https://doi.org/10.1016/j. joen.2007.05.008

27. Barbosa FOG, Gomes JACP, de Araujo MCP. Influence of previous angular deformation on flexural fatigue resistance of K3 Nickel - Titanium rotary instruments. Journal of endodontics 2007; 33(12): 1477-80. DOI: https://doi.org/10.1016/j.joen.2007.08.014

FOG Barbosa JACP Gomes MCP de Araujo Influence of previous angular deformation on flexural fatigue resistance of K3 Nickel - Titanium rotary instrumentsJournal of endodontics2007331214771480https://doi.org/10.1016/j.joen.2007.08.014

28. Johnson E, Lloyd A, Kuttler S, Namerow K. Comparison between a novel Nickel-Titanium alloy and 508 Nitinol on the cyclic fatigue life of profile 25/.04 rotary instruments. J Endod. 2008; 34(11): 1406-9. DOI: https://doi.org/10.1016/j.joen.2008.07.029

E Johnson A Lloyd S Kuttler K Namerow Comparison between a novel Nickel-Titanium alloy and 508 Nitinol on the cyclic fatigue life of profile 25/.04 rotary instrumentsJ Endod.2008341114061409https://doi.org/10.1016/j.joen.2008.07.029

29. Barbosa FOG, Gomes JACP, de Araujo MCP. Influence of electrochemical polishing on the mechanical properties of K3 Nickel-Titanium rotary instruments. J Endod. 2008; 34(12): 1533-6. DOI: https://doi.org/10.1016/j.joen.2008.08.023

FOG Barbosa JACP Gomes MCP de Araujo Influence of electrochemical polishing on the mechanical properties of K3 Nickel-Titanium rotary instrumentsJ Endod.2008341215331536https://doi.org/10.1016/j.joen.2008.08.023

30. Gambarini G, Grande NM, Plotino G, Somma F, Garala M, De Luca M, et al. Fatigue resistance of engine- driven rotary Nickel-Titanium instruments produced by new manufacturing methods. J Endod. 2008; 34(8): 1003-5. DOI: https://doi.org/10.1016/j.joen.2008.05.007

G Gambarini NM Grande G Plotino F Somma M Garala M De Luca Fatigue resistance of engine- driven rotary Nickel-Titanium instruments produced by new manufacturing methodsJ Endod.200834810031005https://doi.org/10.1016/j.joen.2008.05.007

31. Wolle CFB, Vasconcellos MAZ, Hinrichs R, Becker AN, Barletta FB. The effect of argon and nitrogen ion implantation on Nickel-Titanium rotary instruments. J Endod. 2009; 35(11): 1558-62. DOI: https://doi. org/10.1016/j.joen.2009.07.023

CFB Wolle MAZ Vasconcellos R Hinrichs AN Becker FB Barletta The effect of argon and nitrogen ion implantation on Nickel-Titanium rotary instrumentsJ Endod.2009351115581562https://doi. org/10.1016/j.joen.2009.07.023

32. Park SY, Cheung GSP, Yum J, Hur B, Park JK, Kim HC. Dynamic torsional resistance of nickel-titanium rotary instruments. J Endod. 2010; 36(7): 1200-4. DOI: https://doi.org/10.1016/j.joen.2010.02.016

SY Park GSP Cheung J Yum B Hur JK Park HC Kim Dynamic torsional resistance of nickel-titanium rotary instrumentsJ Endod.201036712001204https://doi.org/10.1016/j.joen.2010.02.016

33. Hof R, Perevalov V, Eltanani M, Zary R, Metzger Z. The Self-Adjusting File (SAF). Part 2: mechanical analysis. J Endod. 2010; 36(4): 691-6. DOI: https://doi.org/10.1016/j.joen.2009.12.028

R Hof V Perevalov M Eltanani R Zary Z Metzger The Self-Adjusting File (SAF). Part 2: mechanical analysisJ Endod.2010364691696https://doi.org/10.1016/j.joen.2009.12.028

34. Gao Y, Shotton V, Wilkinson K, Phillips G, Johnson WB. Effects of raw material and rotational speed on the cyclic fatigue of profile vortex rotary instruments. J Endod. 2010; 36(7): 1205-9. DOI: https://doi.org/10.1016/j.joen.2010.02.015

Y Gao V Shotton K Wilkinson G Phillips WB Johnson Effects of raw material and rotational speed on the cyclic fatigue of profile vortex rotary instrumentsJ Endod.201036712051209https://doi.org/10.1016/j.joen.2010.02.015

35. Rodrigues RCV, Lopes HP, Elias CN, Amaral G, Vieira VTL, De Martin AS. Influence of different manufacturing methods on the cyclic fatigue of rotary nickel-titanium endodontic instruments. J Endod. 2011; 37(11): 1553-7. DOI: https://doi.org/10.1016/j.joen.2011.08.011

RCV Rodrigues HP Lopes CN Elias G Amaral VTL Vieira AS De Martin Influence of different manufacturing methods on the cyclic fatigue of rotary nickel-titanium endodontic instrumentsJ Endod.2011371115531557https://doi.org/10.1016/j.joen.2011.08.011

36. Castelló-Escrivá R, Alegre-Domingo T, Faus-Matoses V, Román-Richon S, Faus-Llácer VJ. In vitro comparison of cyclic fatigue resistance of ProTaper, WaveOne, and twisted files. J Endod. 2012; 38(11): 1521-4. DOI: https://doi.org/10.1016/j.joen.2012.07.010

R Castelló-Escrivá T Alegre-Domingo V Faus-Matoses S Román-Richon VJ Faus-Llácer In vitro comparison of cyclic fatigue resistance of ProTaper, WaveOne, and twisted filesJ Endod.2012381115211524https://doi.org/10.1016/j.joen.2012.07.010

37. Miglio C, Grande NM, Plotino G, Milana V, Testarelli L, Gambarini G. Fatica ciclica di nuovi strumenti al nichel-titanio in canali artificiali a singola e doppia curvatura. G Ital Endod. 2012; 26(3): 106-10. DOI: https://doi.org/10.1016/j.gien.2012.09.007

C Miglio NM Grande G Plotino V Milana L Testarelli G Gambarini Fatica ciclica di nuovi strumenti al nichel-titanio in canali artificiali a singola e doppia curvaturaG Ital Endod.2012263106110https://doi.org/10.1016/j.gien.2012.09.007

38. Leroy AMF, Bahia MGDA, Ehrlacher A, Buono VTL. An analytical mechanical model to describe the response of NiTi rotary endodontic files in a curved root canal. Mater Sci Eng C. 2012; 32(6): 1594-1600. DOI: https://doi.org/10.1016/j.msec.2012.04.049

AMF Leroy MGDA Bahia A Ehrlacher VTL Buono An analytical mechanical model to describe the response of NiTi rotary endodontic files in a curved root canalMater Sci Eng C.201232615941600https://doi.org/10.1016/j.msec.2012.04.049

39. Bhagabati N, Yadav S, Talwar S. An in vitro cyclic fatigue analysis of different endodontic nickel-titanium rotary instruments. J Endod. 2012; 38(4): 515-8. DOI: https://doi.org/10.1016/j.joen.2011.12.034

N Bhagabati S Yadav S Talwar An in vitro cyclic fatigue analysis of different endodontic nickel-titanium rotary instrumentsJ Endod.2012384515518https://doi.org/10.1016/j.joen.2011.12.034

40. Ehrhardt IC, Zuolo ML, Cunha RS, De Martin AS, Kherlakian D, de Carvalho MCC, et al. Assessment of the separation incidence of Mtwo files used with preflaring: prospective clinical study. J Endod. 2012; 38(8): 1078-81. DOI: https://doi.org/10.1016/j.joen.2012.05.001

IC Ehrhardt ML Zuolo RS Cunha AS De Martin D Kherlakian MCC de Carvalho Assessment of the separation incidence of Mtwo files used with preflaring: prospective clinical studyJ Endod.201238810781081https://doi.org/10.1016/j.joen.2012.05.001

41. Al-Sudani D, Grande NM, Plotino G, Pompa G, Di Carlo S, Testarelli L et al. Cyclic fatigue of nickel-titanium rotary instruments in a double (S-shaped) simulated curvature. J Endod. 2012; 38(7): 987-9. DOI: https://doi.org/10.1016/j.joen.2012.03.025

D Al-Sudani NM Grande G Plotino G Pompa S Di Carlo L Testarelli Cyclic fatigue of nickel-titanium rotary instruments in a double (S-shaped) simulated curvatureJ Endod.2012387987989https://doi.org/10.1016/j.joen.2012.03.025

42. Bouska J, Justman B, Williamson A, Delong C, Qian F. Resistance to cyclic fatigue failure of a new endodontic rotary file. J Endod. 2012; 38(5): 667-9. DOI: https://doi.org/10.1016/j.joen.2012.01.016

J Bouska B Justman A Williamson C Delong F Qian Resistance to cyclic fatigue failure of a new endodontic rotary fileJ Endod.2012385667669https://doi.org/10.1016/j.joen.2012.01.016

43. Lopes HP, Elias CN, Siqueira JF, Soares RG, Souza LC, Oliveira JCM, et al. Mechanical behavior of pathfinding endodontic instruments. J Endod. 2012; 38(10): 1417-21. DOI: https://doi.org/10.1016/j.joen.2012.05.005

HP Lopes CN Elias JF Siqueira RG Soares LC Souza JCM Oliveira Mechanical behavior of pathfinding endodontic instrumentsJ Endod.2012381014171421https://doi.org/10.1016/j.joen.2012.05.005

44. Capar ID, Ertas H, Arslan H. Comparison of cyclic fatigue resistance of nickel-titanium coronal flaring instruments. J Endod. 2014; 40(8): 1182-5. DOI: https://doi.org/10.1016/j.joen.2013.12.031

ID Capar H Ertas H Arslan Comparison of cyclic fatigue resistance of nickel-titanium coronal flaring instrumentsJ Endod.201440811821185https://doi.org/10.1016/j.joen.2013.12.031

45. Plotino G, Grande NM, Cotti E, Testarelli L, Gambarini G. Blue treatment enhances cyclic fatigue resistance of vortex nickel-titanium rotary files. J Endod. 2014; 40(9): 1451-3. DOI: https://doi.org/10.1016/j.joen.2014.02.020

G Plotino NM Grande E Cotti L Testarelli G Gambarini Blue treatment enhances cyclic fatigue resistance of vortex nickel-titanium rotary filesJ Endod.201440914511453https://doi.org/10.1016/j.joen.2014.02.020

46. Testarelli L, Putortì E, Staffoli S, Obino FV, Nardo DD, Miccoli G, et al. Cyclic fatigue of NiTi instruments used in complex curvatures with continuous or reciprocating rotation. G Ital Endod. 2014; 28(2): 87-90. DOI: https://doi.org/10.1016/j.gien.2014.10.003

L Testarelli E Putortì S Staffoli FV Obino DD Nardo G Miccoli Cyclic fatigue of NiTi instruments used in complex curvatures with continuous or reciprocating rotationG Ital Endod.20142828790https://doi.org/10.1016/j.gien.2014.10.003

47. Pedullà E, Franciosi G, Ounsi HF, Tricarico M, Rapisarda E, Grandini S. Cyclic fatigue resistance of nickel- titanium instruments after immersion in irrigant solutions with or without surfactants. J Endod. 2014; 40(8): 1245-9. DOI: https://doi.org/10.1016/j.joen.2014.02.005

E Pedullà G Franciosi HF Ounsi M Tricarico E Rapisarda S Grandini Cyclic fatigue resistance of nickel- titanium instruments after immersion in irrigant solutions with or without surfactantsJ Endod.201440812451249https://doi.org/10.1016/j.joen.2014.02.005

48. Campbell L, Shen Y, Zhou HM, Haapasalo M. Effect of fatigue on torsional failure of nickel-titanium controlled memory instruments. J Endod. 2014; 40(4): 562-5. DOI: https://doi.org/10.1016/j.joen.2013.12.035

L Campbell Y Shen HM Zhou M Haapasalo Effect of fatigue on torsional failure of nickel-titanium controlled memory instrumentsJ Endod.2014404562565https://doi.org/10.1016/j.joen.2013.12.035

49. Moreira Braga LC, Faria Silva AC, Lopes Buono VT, de Azevedo Bahia MG. Impact of heat treatments on the fatigue resistance of different rotary nickel-titanium instruments. J Endod. 2014; 40(9): 1494-7. DOI: https://doi.org/10.1016/j.joen.2014.03.007

LC Moreira Braga AC Faria Silva VT Lopes Buono MG de Azevedo Bahia Impact of heat treatments on the fatigue resistance of different rotary nickel-titanium instrumentsJ Endod.201440914941497https://doi.org/10.1016/j.joen.2014.03.007

50. Sousa J, Basto J, Roseiro L, Messias A, dos Santos JM, Palma P. Avaliação da fadiga cíclica de 3 sistemas de limas utilizadas em instrumentação mecanizada. Rev Port Estomatol Med Dent e Cir Maxilofac. 2015; 56(4): 239-45. DOI: https://doi.org/10.1016/j.rpemd.2015.11.007

J Sousa J Basto L Roseiro A Messias JM dos Santos P Palma Avaliação da fadiga cíclica de 3 sistemas de limas utilizadas em instrumentação mecanizadaRev Port Estomatol Med Dent e Cir Maxilofac.2015564239245https://doi.org/10.1016/j.rpemd.2015.11.007

51. Capar ID, Kaval ME, Ertas H, Sen BH. Comparison of the cyclic fatigue resistance of 5 different rotary pathfinding instruments made of conventional nickel-titanium wire, M-wire, and controlled memory wire. J Endod. 2015; 41(4): 535-8. DOI: https://doi.org/10.1016/j.joen.2014.11.008

ID Capar ME Kaval H Ertas BH Sen Comparison of the cyclic fatigue resistance of 5 different rotary pathfinding instruments made of conventional nickel-titanium wire, M-wire, and controlled memory wireJ Endod.2015414535538https://doi.org/10.1016/j.joen.2014.11.008

52. Shen Y, Coil JM, Mclean AGR, Hemerling DL, Haapasalo M. Defects in Nickel-Titanium instruments after clinical use. Part 5: single use from endodontic specialty practices. J Endod. 2009; 35(10): 1363-7. DOI: https://doi.org/10.1016/j.joen.2009.07.004

Y Shen JM Coil AGR Mclean DL Hemerling M Haapasalo Defects in Nickel-Titanium instruments after clinical use. Part 5: single use from endodontic specialty practicesJ Endod.2009351013631367https://doi.org/10.1016/j.joen.2009.07.004

53. Pedulla E, Lo Savio F, Plotino G, Grande NM, Rapisarda S, Gambarini G, et al. Effect of cyclic torsional preloading on cyclic fatigue resistance of ProTaper Next and Mtwo nickel-titanium instruments. G Ital Endod. 2015; 29(1): 3-8. DOI: https://doi.org/10.1016/j.gien.2015.05.002

E Pedulla F Lo Savio G Plotino NM Grande S Rapisarda G Gambarini Effect of cyclic torsional preloading on cyclic fatigue resistance of ProTaper Next and Mtwo nickel-titanium instrumentsG Ital Endod.201529138https://doi.org/10.1016/j.gien.2015.05.002

54. Carvalho A, Freitas M, Reis L, Montalvão D, Fonte M. Rotary fatigue testing machine to determine the fatigue life of NiTi alloy wires and endondontic files. Procedia Eng. 2015; 114: 500-5. DOI: https://doi. org/10.1016/j.proeng.2015.08.098

A Carvalho M Freitas L Reis D Montalvão M Fonte Rotary fatigue testing machine to determine the fatigue life of NiTi alloy wires and endondontic filesProcedia Eng.2015114500505https://doi. org/10.1016/j.proeng.2015.08.098

55. Uslu G, Özyürek T, İnan U. Comparison of cyclic fatigue resistance of ProGlider and One G Glide path files. J Endod. 2016; 42(10): 1555-8. DOI: https://doi.org/10.1016/j.joen.2016.07.012

G Uslu T Özyürek U İnan Comparison of cyclic fatigue resistance of ProGlider and One G Glide path filesJ Endod.2016421015551558https://doi.org/10.1016/j.joen.2016.07.012

56. Isidoro J, Martins RF. Calculation of stress intensity factors KI, KII and KIII of cracked components submitted to flexural and torsional loads. Procedia Eng. 2016; 160: 131-6. DOI: https://doi.org/10.1016/j.proeng.2016.08.872

J Isidoro RF Martins Calculation of stress intensity factors KI, KII and KIII of cracked components submitted to flexural and torsional loadsProcedia Eng.2016160131136https://doi.org/10.1016/j.proeng.2016.08.872

57. Özyürek T, Uslu G, İnan U. A comparison of the cyclic fatigue resistance of used and new glide path files. J Endod. 2017; 43(3): 477-80. DOI: https://doi.org/10.1016/j.joen.2016.10.044

T Özyürek G Uslu U İnan A comparison of the cyclic fatigue resistance of used and new glide path filesJ Endod.2017433477480https://doi.org/10.1016/j.joen.2016.10.044

58. Chi CW, Li CC, Lin CP, Shin CS. Cyclic fatigue behavior of nickel-titanium dental rotary files in clinical simulated root canals. J Formos Med Assoc. 2017; 116(4): 306-12. DOI: https://doi.org/10.1016/j. jfma.2016.06.002

CW Chi CC Li CP Lin CS Shin Cyclic fatigue behavior of nickel-titanium dental rotary files in clinical simulated root canalsJ Formos Med Assoc.20171164306312https://doi.org/10.1016/j. jfma.2016.06.002

59. Lopes HP, Elias CN, Vieira MVB, Vieira VTL, De Souza LC, Dos Santos AL. Influence of surface roughness on the fatigue life of Nickel-Titanium rotary endodontic instruments. J Endod. 2016; 42(6): 965-8. DOI: https://doi.org/10.1016/j.joen.2016.03.001

HP Lopes CN Elias MVB Vieira VTL Vieira LC De Souza AL Dos Santos Influence of surface roughness on the fatigue life of Nickel-Titanium rotary endodontic instrumentsJ Endod.2016426965968https://doi.org/10.1016/j.joen.2016.03.001

60. Lo Savio F, Pedullà E, Rapisarda E, La Rosa G. Influence of heat-treatment on torsional resistance to fracture of nickel-titanium endodontic instruments. Procedia Struct Integr. 2016; 2: 1311-8. DOI: https://doi.org/10.1016/j.prostr.2016.06.167

F Lo Savio E Pedullà E Rapisarda G La Rosa Influence of heat-treatment on torsional resistance to fracture of nickel-titanium endodontic instrumentsProcedia Struct Integr.2016213111318https://doi.org/10.1016/j.prostr.2016.06.167

61. Loios G, Martins RF, Ginjeira A, Dragoi M V, Buican G. Fatigue resistance of rotary endodontic files submitted to axial motion in multiplanar canals manufactured by 3D printing. Procedia Eng. 2016; 160: 117-22. DOI: https://doi.org/10.1016/j.proeng.2016.08.870

G Loios RF Martins A Ginjeira V Dragoi M G Buican Fatigue resistance of rotary endodontic files submitted to axial motion in multiplanar canals manufactured by 3D printingProcedia Eng.2016160117122https://doi.org/10.1016/j.proeng.2016.08.870

62. Peláez Acosta E, Damas Resende P, Faria da Cunha I, Sales Joviano É, Lopes Buono VT, de Azevedo Bahia MG. Influence of cyclic flexural deformation on the torsional resistance of controlled memory and conventional Nickel-titanium instruments. J Endod. 2017; 43(4): 613-8. DOI: https://doi.org/10.1016/j.joen.2016.11.007

E Peláez Acosta P Damas Resende I Faria da Cunha É Sales Joviano VT Lopes Buono MG de Azevedo Bahia Influence of cyclic flexural deformation on the torsional resistance of controlled memory and conventional Nickel-titanium instrumentsJ Endod.2017434613618https://doi.org/10.1016/j.joen.2016.11.007

63. Dosanjh A, Paurazas S, Askar M. The effect of temperature on cyclic fatigue of Nickel-titanium rotary endodontic instruments. J Endod. 2017; 43(5): 823-6. DOI: https://doi.org/10.1016/j.joen.2016.12.026

A Dosanjh S Paurazas M Askar The effect of temperature on cyclic fatigue of Nickel-titanium rotary endodontic instrumentsJ Endod.2017435823826https://doi.org/10.1016/j.joen.2016.12.026

64. Grande NM, Plotino G, Silla E, Pedullà E, DeDeus G, ambarini G, et al. Environmental temperature drastically affects flexural fatigue resistance of Nickel-titanium rotary files. J Endod. 2017; 43(7): 1157-60. DOI: https://doi.org/10.1016/j.joen.2017.01.040

NM Grande G Plotino E Silla E Pedullà G DeDeus G ambarini Environmental temperature drastically affects flexural fatigue resistance of Nickel-titanium rotary filesJ Endod.201743711571160https://doi.org/10.1016/j.joen.2017.01.040

65. Chi CW, Deng YL, Lee JW, Lin CP. Fracture resistance of dental nickel-titanium rotary instruments with novel surface treatment: thin film metallic glass coating. J Formos Med Assoc. 2017; 116(5): 373-9. DOI: https://doi.org/10.1016/j.jfma.2016.07.003

CW Chi YL Deng JW Lee CP Lin Fracture resistance of dental nickel-titanium rotary instruments with novel surface treatment: thin film metallic glass coatingJ Formos Med Assoc.20171165373379https://doi.org/10.1016/j.jfma.2016.07.003

66. Ha J, Kwak SW, Sigurdsson A, Chang SW, Kim SK, Kim H. Stress generation during pecking motion of rotary Nickel-titanium instruments with different. J Endod. 2017; 43(10): 1688-91. DOI: https://doi.org/10.1016/j. joen.2017.04.013

J Ha SW Kwak A Sigurdsson SW Chang SK Kim H Kim Stress generation during pecking motion of rotary Nickel-titanium instruments with differentJ Endod.2017431016881691https://doi.org/10.1016/j. joen.2017.04.013

67. Chi CW, Lai EHH, Liu CY, Lin CP, Shin CS. Influence of heat treatment on cyclic fatigue and cutting efficiency of ProTaper Universal F2 instruments. J Dent Sci. 2017; 12(1): 21-6. DOI: https://doi.org/10.1016/j.jds.2016.06.001

CW Chi EHH Lai CY Liu CP Lin CS Shin Influence of heat treatment on cyclic fatigue and cutting efficiency of ProTaper Universal F2 instrumentsJ Dent Sci.20171212126https://doi.org/10.1016/j.jds.2016.06.001

68. Gündoěar M, Özyürek T. Cyclic fatigue resistance of OneShape, HyFlex EDM, WaveOne Gold, and Reciproc Blue Nickel-titanium instruments. J Endod. 2017; 43(7): 1192-6. DOI: https://doi.org/10.1016/j.joen.2017.03.009

M Gündoěar T Özyürek Cyclic fatigue resistance of OneShape, HyFlex EDM, WaveOne Gold, and Reciproc Blue Nickel-titanium instrumentsJ Endod.201743711921196https://doi.org/10.1016/j.joen.2017.03.009

69. Azim AA, Tarrosh M, Azim KA, Piasecki L. Comparison between single-file rotary systems: part 2-the effect of length of the instrument subjected to cyclic loading on cyclic fatigue resistance. J Endod. 2018; 44(12): 1837-42. DOI: https://doi.org/10.1016/j.joen.2018.07.021

AA Azim M Tarrosh KA Azim L Piasecki Comparison between single-file rotary systems: part 2-the effect of length of the instrument subjected to cyclic loading on cyclic fatigue resistanceJ Endod.2018441218371842https://doi.org/10.1016/j.joen.2018.07.021

70. Iacono F, Pirani C, Generali L, Gatto MR, Gandolfi MG, Prati C. Cyclic fatigue resistance of Nickel-Titanium reciprocating instruments tested with an innovative kinematics. G Ital Endod. 2018; 32(1): 42-6. DOI: https://doi.org/10.1016/j.gien.2018.03.004

F Iacono C Pirani L Generali MR Gatto MG Gandolfi C Prati Cyclic fatigue resistance of Nickel-Titanium reciprocating instruments tested with an innovative kinematicsG Ital Endod.20183214246https://doi.org/10.1016/j.gien.2018.03.004

71. Shen Y, Tra C, Hieawy A, Wang Z, Haapasalo M. Effect of torsional and fatigue preloading on hyflex EDM files. J Endod. 2018; 44(4): 643-7. DOI: https://doi.org/10.1016/j.joen.2017.12.002

Y Shen C Tra A Hieawy Z Wang M Haapasalo Effect of torsional and fatigue preloading on hyflex EDM filesJ Endod.2018444643647https://doi.org/10.1016/j.joen.2017.12.002

72. Alfawaz H, Alqedairi A, Alsharekh H, Almuzaini E, Alzahrani S, Jamleh A. Effects of sodium hypochlorite concentration and temperature on the cyclic fatigue resistance of heat-treated Nickel-titanium rotary instruments. J Endod. 2018; 44(10): 1563-6. DOI: https://doi.org/10.1016/j.joen.2018.07.009

H Alfawaz A Alqedairi H Alsharekh E Almuzaini S Alzahrani A Jamleh Effects of sodium hypochlorite concentration and temperature on the cyclic fatigue resistance of heat-treated Nickel-titanium rotary instrumentsJ Endod.2018441015631566https://doi.org/10.1016/j.joen.2018.07.009

73. Bhatt A, Rajkumar B. A comparative evaluation of cyclic fatigue resistance for different endodontic NiTi rotary files: an in-vitro study. J Oral Biol Craniofacial Res. 2019; 9(2): 119-21. DOI: https://doi.org/10.1016/j. jobcr.2018.12.003

A Bhatt B Rajkumar A comparative evaluation of cyclic fatigue resistance for different endodontic NiTi rotary files: an in-vitro studyJ Oral Biol Craniofacial Res.201992119121https://doi.org/10.1016/j. jobcr.2018.12.003

74. Binous H, Bellagi A. Introducing nonlinear dynamics to chemical and biochemical engineering graduate students using MATHEMATICA©. Comput Appl Eng Educ.; 27(1): 217-35. 2018. DOI: https://doi.org/10.1002/cae.22070

H Binous A Bellagi Introducing nonlinear dynamics to chemical and biochemical engineering graduate students using MATHEMATICA©Comput Appl Eng Educ.27121723503052022https://doi.org/10.1002/cae.22070

75. Barbosa IB, Scelza P, Pereira AMB, Ferreira FG, Bagueira R, Adeodato CSR, et al. Progressive structural deterioration of an endodontic instrument: a preliminary micro-computed tomography study. Eng Fail Anal. 2019; 104: 105-11. DOI: https://doi.org/10.1016/j.engfailanal.2019.05.029

IB Barbosa P Scelza AMB Pereira FG Ferreira R Bagueira CSR Adeodato Progressive structural deterioration of an endodontic instrument: a preliminary micro-computed tomography studyEng Fail Anal.2019104105111https://doi.org/10.1016/j.engfailanal.2019.05.029

76. Piasecki L, Makowka SR, Gambarini G. Anatomic two-dimensional and three-dimensional models for cyclic fatigue testing of endodontic instruments. Iran Endod J. 2020; 15(2): 100-5. DOI: https://doi.org/10.22037/iej.v15i2.27342

L Piasecki SR Makowka G Gambarini Anatomic two-dimensional and three-dimensional models for cyclic fatigue testing of endodontic instrumentsIran Endod J.2020152100105https://doi.org/10.22037/iej.v15i2.27342

77. Miccoli G, Seracchiani M, Del Giudice A, Mazonni A, D’Angelo M, Bhandi S, et al. Fatigue resistance of two Nickel-Titanium rotary instruments before and after ex vivo root canal treatment. J Contemp Dent Pract. 2020; 21(7): 728-32. DOI: http://dx.doi.org/10.5005/jp-journals-10024-2875

G Miccoli M Seracchiani A Del Giudice A Mazonni M D’Angelo S Bhandi Fatigue resistance of two Nickel-Titanium rotary instruments before and after ex vivo root canal treatmentJ Contemp Dent Pract.2020217728732http://dx.doi.org/10.5005/jp-journals-10024-2875

78. Generali L, Malovo A, Bolelli G, Borghi A, La Rosa GRM, Puddu P, et al. Mechanical Properties and Metallurgical Features of New Green NiTi Reciprocating Instruments. Materials. 2020; 13(17): 3736. DOI: https:// doi.org/10.3390/ma13173736

L Generali A Malovo G Bolelli A Borghi GRM La Rosa P Puddu Mechanical Properties and Metallurgical Features of New Green NiTi Reciprocating InstrumentsMaterials2020131737363736https:// doi.org/10.3390/ma13173736

79. Drukteinis S, Peciuliene V, Bendinskaite R, Brukiene V, Maneliene R, Rutkunas V. Shaping and centering ability, cyclic fatigue resistance and fractographic analysis of three thermally treated niti endodontic instrument systems. Materials (Basel). 2020; 13(24): 1-13. DOI: https://doi.org/10.3390/ma13245823

S Drukteinis V Peciuliene R Bendinskaite V Brukiene R Maneliene V Rutkunas Shaping and centering ability, cyclic fatigue resistance and fractographic analysis of three thermally treated niti endodontic instrument systemsMaterials (Basel)20201324113https://doi.org/10.3390/ma13245823

80. Zubizarreta-Macho Á, Albaladejo Martínez A, Falcão Costa C, Quispe-López N, Agustín-Panadero R, Mena- Álvarez J. Influence of the type of reciprocating motion on the cyclic fatigue resistance of reciprocating files in a dynamic model. BMC Oral Health. 2021; 21(1): 1-10.

Á Zubizarreta-Macho A Albaladejo Martínez C Falcão Costa N Quispe-López R Agustín-Panadero J Mena- Álvarez Influence of the type of reciprocating motion on the cyclic fatigue resistance of reciprocating files in a dynamic modelBMC Oral Health.2021211110

81. Hou XM, Yang YJ, Qian J. Phase transformation behaviors and mechanical properties of NiTi endodontic files aftegold heat treatment and blue heat treatment. J Oral Sci. 2021; 63(1): 8-13. DOI: https://doi.org/10.2334/josnusd.19-0331

XM Hou YJ Yang J Qian Phase transformation behaviors and mechanical properties of NiTi endodontic files aftegold heat treatment and blue heat treatmentJ Oral Sci.2021631813https://doi.org/10.2334/josnusd.19-0331

82. Faus-Llácer V, Kharrat NH, Ruiz-Sánchez C, Faus-Matoses I, Zubizarreta-Macho Á, Faus-Matoses V. The effect of taper and apical diameter on the cyclic fatigue resistance of rotary endodontic files using an experimental electronic device. Appl Sci. 2021; 11(2): 1-14. DOI: https://doi.org/10.3390/app11020863

V Faus-Llácer NH Kharrat C Ruiz-Sánchez I Faus-Matoses Á Zubizarreta-Macho V Faus-Matoses The effect of taper and apical diameter on the cyclic fatigue resistance of rotary endodontic files using an experimental electronic deviceAppl Sci.2021112114https://doi.org/10.3390/app11020863

83. Costanzo A, Vincenzi V, Giansiracusa A, Milana V, Marconi V, Pietrangeli, et al. Influenza della sterilizzazione su strumenti fabbricati con leghe trattate termicamente. G Ital Endod. 2011; 25(2): 67-71. DOI: https://doi.org/10.1016/j.gien.2011.06.002

Vincenzi V Costanzo A Milana V Giansiracusa A Pietrangeli Marconi V Influenza della sterilizzazione su strumenti fabbricati con leghe trattate termicamenteG Ital Endod.20112526771https://doi.org/10.1016/j.gien.2011.06.002

[3]How to quote this article: Orozco-Ocampo YM, Álvarez-Vargas CA, Jiménez-García FN, Escobar- Rincón D, Jaramillo-Gil PX. Fatigue failure of NiTi endodontic files: soping review of thematic coverage. Rev Fac Odontol Univ Antioq. 2022; 34(1): 14-30. DOI: http://dx.doi.org/10.17533/udea.rfo.v34n1a6.