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Subramanian SK, Joshi V, Kalra S, Adhikari S. Unveiling the fatigue life of NiTi endodontic files: An integrated computational-experimental study. J Mech Behav Biomed Mater 2024; 157:106657. [PMID: 39024733 DOI: 10.1016/j.jmbbm.2024.106657] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2024] [Revised: 07/03/2024] [Accepted: 07/07/2024] [Indexed: 07/20/2024]
Abstract
Nickel-titanium (NiTi) rotary files used in root canal treatments experience fatigue and shear damage due to the complex curved geometries and operating conditions encountered within the root canal. This can lead to premature file fracture, causing severe complications. A comprehensive understanding of how different factors contribute to file damage is crucial for improving their functional life. This study investigates the combined effects of root canal curvature radius, file canal curvature, and rotational speed on the fatigue life and failure modes of NiTi endodontic files through an integrated computational and experimental approach. Advanced finite element simulations precisely replicating the dynamic motion of files inside curved canal geometries were conducted. Critical stress/strain values were extracted and incorporated into empirical fatigue models to predict the functional life of endodontic files. Extensive experiments with files rotated inside artificial curved canals at various canal curvatures and speeds provided validation. Increasing the canal curvature beyond 60∘ and shorter curvature radii below 5 mm dramatically reduced the functional life of the endodontic file, especially at rotational speeds over 360 rpm. The Coffin-Manson fatigue model based on strain amplitude showed the closest agreement with experiments. Shear stresses dominated damage at low canal curvatures, while the combined shear-fatigue loading effects were prominent at higher canal curvatures. This conclusive study elucidates how operational parameters like canal curvature radii, canal curvature, and rotational speed synergistically influence the fatigue damage processes in NiTi files. The findings offer valuable guidelines to optimize these factors, significantly extending the functional life of endodontic files and reducing the risk of intra-operative failures. The validated computational approach provides a powerful tool for virtual testing and estimation of the functional life of the new file designs before manufacturing.
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Affiliation(s)
| | - Vivek Joshi
- Department of Mechanical Engineering, Indian Institute of Technology Jammu, India.
| | - Sahil Kalra
- Department of Mechanical Engineering, Indian Institute of Technology Jammu, India.
| | - Sondipon Adhikari
- James Watt School of Engineering, The University of Glasgow, Glasgow G12 8QQ, UK.
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Pedullà E, Carlesi T, Pappalardo A, Canova FS, Malagnino VA, La Rosa GRM, Generali L. Impact of pecking amplitude on cyclic fatigue of new nickel-titanium files. Clin Exp Dent Res 2024; 10:e811. [PMID: 38053521 PMCID: PMC10860459 DOI: 10.1002/cre2.811] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Revised: 10/31/2023] [Accepted: 11/05/2023] [Indexed: 12/07/2023] Open
Abstract
OBJECTIVES The aim of this study is to determine the cyclic fatigue resistance of Mtwo Minimal in static and dynamic tests, with different amplitudes of pecking movements, at intracanal temperature. MATERIALS AND METHODS Two hundred new 25-mm Mtwo Minimal rotary files (#10/0.035, #17.5/0.045, #25/0.05, #40/0.03, #45/0.03) were tested in static and dynamic cyclic fatigue tests at 35°C (±1°C). An artificial stainless-steel canal was used. In the dynamic mode, axial movements were set at 1 and 3 mm. The number of cycles to fracture (NCF) was recorded and statistically analyzed by one-way analysis of variance (p < 0.05). RESULTS The 3-mm dynamic test showed significantly increased NCF than the other tests for the #10/0.035, #17.5/0.045, and #25/0.05 files (p < 0.05). The #40/0.03 and #45/0.03 files showed no significant differences in all the tests (p > 0.05). CONCLUSION Mtwo Minimal showed higher cyclic fatigue resistance in the dynamic test than the static test, except for the larger instruments. The 3-mm pecking amplitude increased the cyclic fatigue resistance of the smaller instruments.
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Affiliation(s)
- Eugenio Pedullà
- Department of General Surgery and Medical‐Surgical SpecialtiesUniversity of CataniaCataniaItaly
| | - Teocrito Carlesi
- Department of Medical, Oral and Biotechnological Sciences, Faculty of Medicine and SurgeryUniversity of Chieti—Pescara “G. D'Annunzio”ChietiItaly
- Department of Innovative Technologies in Medicine and Dentistry, Faculty of Medicine and SurgeryUniversity of Chieti—Pescara “G. D'Annunzio”ChietiItaly
| | | | | | - Vito Antonio Malagnino
- Department of Innovative Technologies in Medicine and Dentistry, Faculty of Medicine and SurgeryUniversity of Chieti—Pescara “G. D'Annunzio”ChietiItaly
| | | | - Luigi Generali
- Department of Surgery, Medicine, Dentistry and Morphological Sciences with Transplant Surgery, Oncology and Regenerative Medicine RelevanceUniversity of Modena and Reggio EmiliaModenaItaly
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La Rosa GRM, Leotta ML, Canova FS, Romeo VR, Cervino G, Generali L, Pedullà E. Cyclic fatigue resistance of different nickel-titanium instruments in single and double curvature at room and body temperatures: A laboratory study. AUST ENDOD J 2023; 49:592-598. [PMID: 37592880 DOI: 10.1111/aej.12789] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Accepted: 08/07/2023] [Indexed: 08/19/2023]
Abstract
The aim of this study was to compare the cyclic fatigue resistance of nickel-titanium instruments inside single and double-curved canals at different temperatures. 160 HyFlex EDM #20.05 (HEDM), VDW.ROTATE #20.05 and #25.06, Mtwo #25.06 were randomised (n = 10) for the dynamic cyclic fatigue tests according to the curvature (i.e. single and double) at 20° ± 1°C and 35° ± 1°C. The number of cycles to fracture (NCF) was analysed by two-way ANOVA with p < 0.05. Fatigue resistance of all instruments significantly decreased at body temperature in single and double curvatures, except for HEDM in double curvature. The NCF was significantly lower in double curvature than single at both temperatures for all files, except for VDW.ROTATE #20.05 at 35° ± 1°C. Within the study limitations, temperature significantly impaired cyclic fatigue resistance of all files except HEDM #20.05 in double curvature. Similarly, double curvature had a detrimental effect on cyclic fatigue resistance of all files except for VDW.ROTATE #20.05 at body temperature.
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Affiliation(s)
- Giusy Rita Maria La Rosa
- Department of General Surgery and Medical-Surgical Specialties, University of Catania, Catania, Italy
| | - Maria Laura Leotta
- Department of General Surgery and Medical-Surgical Specialties, University of Catania, Catania, Italy
| | - Francesco Saverio Canova
- Department of General Surgery and Medical-Surgical Specialties, University of Catania, Catania, Italy
| | - Virginia Rosy Romeo
- Department of General Surgery and Medical-Surgical Specialties, University of Catania, Catania, Italy
| | - Gabriele Cervino
- Department of Biomedical and Dental Sciences and Morphological and Functional Imaging, Messina University, Messina, Italy
| | - Luigi Generali
- Department of Surgery, Medicine, Dentistry and Morphological Sciences with Transplant Surgery, Oncology and Regenerative Medicine Relevance (CHIMOMO), University of Modena and Reggio Emilia, Modena, Italy
| | - Eugenio Pedullà
- Department of General Surgery and Medical-Surgical Specialties, University of Catania, Catania, Italy
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Hiran-Us S, Morakul S. Effect of Temperatures on Cyclic Fatigue Resistance of 3 Different Ni-Ti Alloy Files. Int Dent J 2023; 73:904-909. [PMID: 37423864 PMCID: PMC10658440 DOI: 10.1016/j.identj.2023.06.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2023] [Revised: 05/24/2023] [Accepted: 06/20/2023] [Indexed: 07/11/2023] Open
Abstract
OBJECTIVE The aim of this study was to investigate and compare the effect of temperature on the cyclic fatigue resistance of conventional (ProTaper Universal [PTU]), Gold-Wire (ProTaper Gold [PTG]), and Fire-Wire (EdgeTaper Platinum [ETP]) nickel-titanium alloy files. METHOD Twenty files from each system were tested for cyclic fatigue resistance in an artificial canal model. The experiments were performed at room temperature and body temperature in controlled temperature water. Magnified videos were recorded using a dental operating microscope integrated camera during testing to detect file fracture. The number of cycles to failure (NCF) was calculated. The type of failure was investigated macroscopically and microscopically with a dental operating microscope and scanning electron microscope, respectively. RESULT The NCF at room temperature was significantly higher compared with body temperature in each system (P < .001). Compared at the same temperature, the ETP group demonstrated the highest NCF, followed by the PTG and PTU groups (P < .001). All files demonstrated cyclic fatigue failure macroscopically and microscopically. CONCLUSIONS The 3 alloy files were affected by temperature. The cyclic fatigue resistance was reduced at the higher temperature and increased at the lower temperature. If the files are geometrically identical, files made of Fire-Wire are preferred compared with Gold-Wire and conventional nickel-titanium alloys based on cyclic fatigue resistance.
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Affiliation(s)
- Sirawut Hiran-Us
- Department of Operative Dentistry, Faculty of Dentistry, Chulalongkorn University, Bangkok, Thailand.
| | - Sarita Morakul
- Composite Structures Research Unit, Department of Mechanical Engineering, Faculty of Engineering, Chulalongkorn University, Bangkok, Thailand
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Jamleh A, Albanyan H, Alaqla A, Alissa H, Alshetan N, Alraffa S, Alfadley A. Impact of cooling on shaping ability of thermally treated files in canal models with double curvature. PeerJ 2023; 11:e15830. [PMID: 37576504 PMCID: PMC10416767 DOI: 10.7717/peerj.15830] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Accepted: 07/11/2023] [Indexed: 08/15/2023] Open
Abstract
Background This study compared the ability of thermally treated files in shaping simulated canals with double curvature. Fifty-six canals were enlarged to a final size of 25 with ProTaper Next (PTN) or ZenFlex (ZF). Materials Half of the samples were shaped with cooled files (n = 14 each). The amount of removed resin was measured and canal deviation was determined at eight levels. Shaping time and maximum shaping torque values were also recorded. Data were statistically analyzed using analysis of variance and LSD, Kruskal-Wallis, and chi-square tests at a 0.05 significance level. Results Compared to PTN and cooled PTN, ZF and cooled ZF required lesser time to shape the canals. The maximum torques were found comparable between the groups. All the groups generated negligible deviations at every canal level evaluated and maintained the canal geometry. Although not significant, the cooled PTN and ZF files exhibited lesser canal deviations than their counterparts. Conclusion All groups demonstrated similar shaping ability whilst maintaining the original curvature of the canal in simulated canals with double curvature. However, ZF groups were able to shape the canals faster than PTN groups. There was a trend that cooled files made lesser canal deviations compared to their counterparts.
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Affiliation(s)
- Ahmed Jamleh
- Department of Restorative and Prosthetic Dental Sciences, College of Dentistry, King Saud bin Abdulaziz University for Health Sciences, Riyadh, Saudi Arabia
- King Abdullah International Medical Research Center, Riyadh, Saudi Arabia
| | - Hajar Albanyan
- Department of Restorative and Prosthetic Dental Sciences, College of Dentistry, King Saud bin Abdulaziz University for Health Sciences, Riyadh, Saudi Arabia
- King Abdullah International Medical Research Center, Riyadh, Saudi Arabia
| | - Ali Alaqla
- Department of Restorative and Prosthetic Dental Sciences, College of Dentistry, King Saud bin Abdulaziz University for Health Sciences, Riyadh, Saudi Arabia
- King Abdullah International Medical Research Center, Riyadh, Saudi Arabia
| | - Hamad Alissa
- Department of Restorative and Prosthetic Dental Sciences, College of Dentistry, King Saud bin Abdulaziz University for Health Sciences, Riyadh, Saudi Arabia
- King Abdullah International Medical Research Center, Riyadh, Saudi Arabia
| | - Nawaf Alshetan
- Dr. Sulaiman Al-Habib Medical Group, Riyadh, Saudi Arabia
| | | | - Abdulmohsen Alfadley
- Department of Restorative and Prosthetic Dental Sciences, College of Dentistry, King Saud bin Abdulaziz University for Health Sciences, Riyadh, Saudi Arabia
- King Abdullah International Medical Research Center, Riyadh, Saudi Arabia
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Influence of different heat treatments and temperatures on the cyclic fatigue resistance of endodontic instruments with the same design. Clin Oral Investig 2022; 27:1793-1798. [PMID: 36454355 DOI: 10.1007/s00784-022-04808-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Accepted: 11/27/2022] [Indexed: 12/04/2022]
Abstract
OBJECTIVES To evaluate the influence of different heat treatments and temperatures on the cyclic fatigue resistance of 2Shape instruments (Micro Mega, Besancon, France) with the same design. MATERIALS AND METHODS A total of 80 2Shape TS1 (#25/.04) and 80 TS2 (#25/.06) files with different heat treatments (no heat-treated, NHT; C-Wire; T-Wire; CM-Wire) were tested at room (25° ± 1 °C) and body (37° ± 1 °C) temperatures in 16-mm stainless steel artificial canal with a curvature of 60° and 5 mm of radius. Files were tested in continuous rotation at 300 rpm using a customized device. Cyclic fatigue resistance was expressed in the number of cyclic to fracture (NCF). The phase transformation temperature of each file was determined by differential scanning calorimetry. Data were statistically analyzed using the two-way ANOVA and the Bonferroni post-hoc test with p < 0.05. RESULTS All CM-Wire TS1 and TS2 files showed higher NCF than the other groups at both temperatures (p < 0.001). C-Wire TS2 showed higher resistance than NHT and T-Wire TS2 (p < 0.001), with no significant differences between the last two. Body temperature significantly decreased NCF of all tested files (p < 0.05) except for NHT and T-Wire TS1. CONCLUSIONS Body temperature negatively affected the cyclic fatigue resistance of C-Wire and CM-Wire TS1 and of all TS2 files compared with room temperature. The CM-Wire instruments exhibited the highest cyclic fatigue resistance of all tested files. CLINICAL RELEVANCE Heat-treated nickel-titanium files can differently perform according to environmental temperature and file dimensions. The CM-Wire 2Shape prototypes displayed the highest flexural resistance in all experimental conditions.
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Pedullà E, Canova FS, La Rosa GRM, Naaman A, Diemer F, Generali L, Nehme W. Influence of NiTi Wire Diameter on Cyclic and Torsional Fatigue Resistance of Different Heat-Treated Endodontic Instruments. MATERIALS (BASEL, SWITZERLAND) 2022; 15:6568. [PMID: 36233910 PMCID: PMC9572814 DOI: 10.3390/ma15196568] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Revised: 09/14/2022] [Accepted: 09/19/2022] [Indexed: 06/16/2023]
Abstract
We compared the mechanical properties of 2Shape mini TS2 (Micro-Mega, Besançon, France) obtained from 1.0 diameter nickel-titanium (NiTi) wires and 2Shape TS2 from 1.2 diameter nickel-titanium (NiTi) wires differently thermally treated at room and body temperature. We used 120 NiTi TS2 1.0 and TS2 1.2 files made from controlled memory (CM) wire and T-wire (n = 10). Cyclic fatigue resistance was tested by recording the number of cycles to fracture (NCF) at room and body temperatures using a customized testing device. Maximum torque and angle of rotation at failure were recorded, according to ISO 3630-1. Data were analyzed by a two-way ANOVA (p < 0.05). The CM-wire files had significantly higher NCFs at both temperatures, independent of wire dimensions. Testing at body temperature negatively affected cyclic fatigue of all files. The 1.0-mm diameter T-wire instruments showed higher NCF than the 1.2-mm diameter, whereas no significant differences emerged between the two CM wires at either temperature. The maximum torque was not significantly different across files. The TS2 CM-wire files showed significantly higher angular rotation to fracture than T-wire files. The TS2 CM-wire prototypes showed higher cyclic fatigue resistance than T-wire prototypes, regardless of wire size, exhibiting suitable torsional properties. Torsional behavior appears to not be affected by NiTi wire size.
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Affiliation(s)
- Eugenio Pedullà
- Department of General Surgery and Medical-Surgical Specialties, University of Catania, Via Santa Sofia, 78, 95123 Catania, Italy
| | - Francesco Saverio Canova
- Department of General Surgery and Medical-Surgical Specialties, University of Catania, Via Santa Sofia, 78, 95123 Catania, Italy
| | - Giusy Rita Maria La Rosa
- Department of General Surgery and Medical-Surgical Specialties, University of Catania, Via Santa Sofia, 78, 95123 Catania, Italy
| | - Alfred Naaman
- Endodontic Department, Saint Joseph University of Beirut, Rue de Damas P.O. Box 17-5208, Beirut 1104 2020, Lebanon
| | - Franck Diemer
- Restorative and Endodontic Department, CHU de Toulouse, University of Toulouse, 31013 Toulouse, France
- Clement Ader Institute, UMR CNRS 5312, 31400 Toulouse, France
| | - Luigi Generali
- Endodontic Section, Department of Surgery, Medicine, Dentistry and Morphological Sciences with Transplant Surgery, Oncology and Regenerative Medicine Relevance (CHIMOMO), School of Dentistry, University of Modena and Reggio Emilia, 41125 Modena, Italy
| | - Walid Nehme
- Endodontic Department, Saint Joseph University of Beirut, Rue de Damas P.O. Box 17-5208, Beirut 1104 2020, Lebanon
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Gouédard C, Pino L, Arbab-Chirani R, Arbab-Chirani S, Chevalier V. Comparison of the cyclic fatigue resistance of One Curve, F6 Skytaper, Protaper Next, and Hyflex CM endodontic files. Restor Dent Endod 2022; 47:e16. [PMID: 35692224 PMCID: PMC9160766 DOI: 10.5395/rde.2022.47.e16] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Revised: 10/18/2021] [Accepted: 11/03/2021] [Indexed: 11/11/2022] Open
Abstract
Objectives This study compared the cyclic fatigue resistance of One Curve (C wire) and F6 Skytaper (conventional austenite nickel-titanium [NiTi]), and 2 instruments with thermo-mechanically treated NiTi: Protaper Next X2 (M wire) and Hyflex CM (CM wire). Materials and Methods Ten new instruments of each group (size: 0.25 mm, 6% taper in the 3 mm tip region) were tested using a rotary bending machine with a 60° curvature angle and a 5 mm curvature radius, at room temperature. The number of cycles until fracture was recorded. The length of the fractured instruments was measured. The fracture surface of each fragment was examined with a scanning electron microscope (SEM). The data were analyzed using one-way analysis of variance and the post hoc Tukey test. The significance level was set at 0.05. Results At 60°, One Curve, F6 Skytaper and Hyflex CM had significantly longer fatigue lives than Protaper Next X2 (p < 0.05). No statistically significant differences were found in the cyclic fatigue lives of One Curve, F6 Skytaper, and Hyflex CM (p > 0.05). SEM images of the fracture surfaces of the different instruments showed typical features of fatigue failure. Conclusions Within the conditions of this study, at 60° and with a 5 mm curvature radius, the cyclic fatigue life of One Curve was not significantly different from those of F6 Skytaper and Hyflex CM. The cyclic fatigue lives of these 3 instruments were statistically significantly longer than that of Protaper Next.
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Affiliation(s)
- Charlotte Gouédard
- Department of Pediatric Dentistry, Dental School-Hospital of Brest, France.,University of Bretagne Occidentale, Brest, France
| | - Laurent Pino
- Ecole Nationale d'Ingénieurs de Brest, Brest, France
| | - Reza Arbab-Chirani
- Department of Endodontics and Restorative Dentistry, Dental School-Hospital of Brest, University of Bretagne Occidentale, Brest, France.,Laboratory of Medical Information Processing, Brest, France
| | | | - Valérie Chevalier
- University of Bretagne Occidentale, Brest, France.,Ecole Nationale d'Ingénieurs de Brest, Brest, France
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La Rosa GRM, Shumakova V, Isola G, Indelicato F, Bugea C, Pedullà E. Evaluation of the Cyclic Fatigue of Two Single Files at Body and Room Temperature with Different Radii of Curvature. MATERIALS 2021; 14:ma14092256. [PMID: 33925573 PMCID: PMC8123902 DOI: 10.3390/ma14092256] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/21/2021] [Revised: 04/12/2021] [Accepted: 04/25/2021] [Indexed: 02/07/2023]
Abstract
Background: To compare the influence of different temperatures and curvature radii on the cyclic fatigue resistance of F6 SkyTaper (F6ST) and One Curve (OC) single file nickel-titanium rotary instruments. Methods: A total of 120 instruments of F6ST and OC #25.06 were evaluated in 5 mm and 3 mm curvature radii at two temperatures (20 °C ± 1 °C and 37 °C ± 1 °C) in 16 mm stainless steel artificial canals associated with a curvature of 60°. The cyclic fatigue of tested files was assessed by employing a customized testing apparatus and expressed as times to fracture (TtF). A statistical analysis was performed with the significance level set at 95%. Results: All instruments decreased their TtF at 37 °C except for OC in the 3 mm radius, in which no significant difference was detected between 20 °C and 37 °C. A 3 mm curvature radius negatively affected TtF of all tested instruments, except for F6ST at 20 °C. F6ST had higher TtF than OC in the 3 mm radius at 20 °C, with no significant difference between them in the other tested conditions. Conclusions: Under the limits of the present in vitro study, body temperature impaired cyclic fatigue resistance of all files, except for OC in the 3 mm curvature radius. All instruments exhibited lower times to fracture in the 3 mm radius, excluding F6ST at 20 °C.
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Affiliation(s)
- Giusy Rita Maria La Rosa
- Department of General Surgery and Medical-Surgical Specialties, University of Catania, Plebiscito 628, 95124 Catania, Italy; (V.S.); (G.I.); (F.I.); (E.P.)
- Correspondence:
| | - Valeria Shumakova
- Department of General Surgery and Medical-Surgical Specialties, University of Catania, Plebiscito 628, 95124 Catania, Italy; (V.S.); (G.I.); (F.I.); (E.P.)
| | - Gaetano Isola
- Department of General Surgery and Medical-Surgical Specialties, University of Catania, Plebiscito 628, 95124 Catania, Italy; (V.S.); (G.I.); (F.I.); (E.P.)
| | - Francesco Indelicato
- Department of General Surgery and Medical-Surgical Specialties, University of Catania, Plebiscito 628, 95124 Catania, Italy; (V.S.); (G.I.); (F.I.); (E.P.)
| | | | - Eugenio Pedullà
- Department of General Surgery and Medical-Surgical Specialties, University of Catania, Plebiscito 628, 95124 Catania, Italy; (V.S.); (G.I.); (F.I.); (E.P.)
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