Mechanical behavior of deep cryogenically treated martensitic shape memory nickel–titanium rotary endodontic instruments

ABSTRACT Objectives: The aim of this study was to investigate the role of deep cryogenic treatment (DCT) on the cyclic fatigue resistance and cutting efficiency of martensitic shape memory (SM) nickel–titanium (NiTi) rotary endodontic instruments. Materials and Methods: Seventy-five HyFlex® CM instruments were randomly divided into three groups of 25 each and subjected to different DCT (–185°C) conditions based on soaking time: DCT 24 group: 24 h, DCT 6 group: 6 h, and control group. Each group was randomly subdivided for evaluation of cyclic fatigue resistance in custom-made artificial canals (n = 15) and cutting efficiency in plexiglass simulators (n = 10). The cyclic fatigue resistance was measured by calculating the number of cycles to failure (NCF) and cutting efficiency was measured using the loss of weight method. Results: Increase in NCF of instruments in DCT 24 group was highly significant (P < 0.01; Tukey's honest significant difference). There was no difference in weight loss of plexiglass simulators in all the groups (P > 0.05; one-way analysis of variance). In conclusion, deep dry cryogenic treatment with 24 h soaking time significantly increases the cyclic fatigue resistance without affecting the cutting efficiency of SM NiTi endodontic instruments.

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Effect of synchronous irrigation on cyclic fatigue of nickel-titanium instrument in the dynamic and static models

Journal of Applied Biomaterials & Functional Materials ◽

10.1177/2280800020987403 ◽

2021 ◽

Vol 19 ◽

pp. 228080002098740

Author(s):

Haiyun Liu ◽

Yanfeng Li ◽

Guangquan Chai ◽

Yuan Lv ◽

Changjian Li ◽

...

Keyword(s):

Fatigue Resistance ◽

Flow Rate ◽

Dynamic Control ◽

Cyclic Fatigue ◽

Nickel Titanium ◽

Control Group ◽

Time To Failure ◽

Dynamic Tests ◽

Significant Difference ◽

Experimental Group

Objective: To evaluate the effect of synchronous water irrigation on the fatigue resistance of nickel-titanium instrument. Methods: A standardized cyclic fatigue test models were established, and five types of nickel-titanium instruments (PTU F1, WO, WOG, RE, and M3) were applied. Each instrument was randomly divided into two groups ( N = 12). There was synchronous water irrigation in the experimental group, and no water irrigation in the control group. Besides, ProTaper Universal F1 was randomly divided into 10 groups ( N = 20). In the static group, nickel-titanium instruments were divided into one control group (no irrigation, N = 20) and six experimental group (irrigation, N = 20) based on different flow rate, angle and position; while in the dynamic group, instruments were divided into one control group (no irrigation, N = 20) and two experimental group (irrigation, N = 20) based on different flow rate. The rotation time (Time to Failure, TtF) of instruments was recorded and analyzed. Results: According to the static experiments, the TtF of instruments in all experimental groups was significantly higher than that in the static control group. Besides, the dynamic tests of PTU F1 showed that the TtF in the experimental group was significantly higher than that in the dynamic control group. Compared with control group, the TtF in the experimental groups increased by at least about 30% and up to 160%. The static and dynamic tests of PTU F1 showed that the TtF of nickel-titanium instrument in all experimental groups was significantly higher than that in the control group. However, there was no significant difference between any two experimental groups. Conclusion: Regardless of dynamic or static model, TtF with irrigation was longer than that with non-irrigation, indicating that synchronous irrigation can increase the fatigue resistance of nickel-titanium instrument. However, different irrigation conditions may have the same effect on the fatigue resistance.

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Effect of dry cryogenic treatment on Vickers hardness and wear resistance of new martensitic shape memory nickel-titanium alloy

European Journal of Dentistry ◽

10.4103/1305-7456.172626 ◽

2015 ◽

Vol 09 (04) ◽

pp. 513-517 ◽

Cited By ~ 5

Author(s):

Thilla Sekar Vinothkumar ◽

Deivanayagam Kandaswamy ◽

Gopalakrishnan Prabhakaran ◽

Arunachalam Rajadurai

Keyword(s):

Weight Loss ◽

Wear Resistance ◽

Shape Memory ◽

Vickers Hardness ◽

Niti Alloy ◽

Cryogenic Treatment ◽

Nickel Titanium ◽

Control Group ◽

Deep Cryogenic Treatment ◽

Significant Difference

ABSTRACT Objectives: The aim of this study is to investigate the role of dry cryogenic treatment (CT) temperature and time on the Vickers hardness and wear resistance of new martensitic shape memory (SM) nickel-titanium (NiTi) alloy. The null hypothesis tested was that there is no difference in Vickers hardness and wear resistance between SM NiTi alloys following CT under two soaking temperatures and times. Materials and Methods: The composition and the phase transformation behavior of the alloy were examined by X-ray energy dispersive spectroscopy and differential scanning calorimetry, respectively. Fifteen cylindrical specimens and 50 sheet specimens were subjected to different CT conditions: Deep cryogenic treatment (DCT) 24 group: −185°C, 24 h; DCT six group: −185°C, 6 h; shallow cryogenic treatment (SCT) 24 group: −80°C, 24 h; SCT six group: −80°C, 6 h; and control group. Wear resistance was assessed from weight loss before and after reciprocatory wet sliding wear. Results: The as-received SM NiTi alloy contained 50.8 wt% nickel and possessed austenite finish temperature (Af) of 45.76°C. Reduction in Vickers hardness of specimens in DCT 24 group was highly significant (P < 0.01; Tukey's honest significant difference [HSD]). The weight loss was significantly higher in DCT 24 group (P < 0.05; Tukey's HSD). Conclusion: Deep dry CT with 24 h soaking period significantly reduces the hardness and wear resistance of SM NiTi alloy.

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

Journal of Dental Research Dental Clinics Dental Prospects ◽

10.15171/joddd.2018.044 ◽

2018 ◽

Vol 12 (4) ◽

pp. 283-287 ◽

Cited By ~ 1

Author(s):

Gülşah Uslu ◽

Taha Özyürek ◽

Mustafa Gündoğar ◽

Koray Yılmaz

Keyword(s):

Fatigue Resistance ◽

Statistical Significance ◽

Cyclic Fatigue ◽

Nickel Titanium ◽

Bonferroni Correction ◽

Significant Difference ◽

Inner Diameter ◽

The Difference ◽

Number Of Cycles ◽

Analyze Data

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

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Impact of Peracetic Acid on the Dynamic Cyclic Fatigue of Heat-Treated Nickel-Titanium Rotary Endodontic Instrument

International Journal of Dentistry ◽

10.1155/2021/6676005 ◽

2021 ◽

Vol 2021 ◽

pp. 1-11

Author(s):

Suhad Jabbar Hamed Al-Nasrawi ◽

Zuha Ayad Jaber ◽

Nibrass Talib Al-Quraine ◽

Abtesam Imhemed Aljdaimi ◽

Sattar Jabbar Abdul-Zahra Al-Hmedat ◽

...

Keyword(s):

Fatigue Resistance ◽

Peracetic Acid ◽

Cyclic Fatigue ◽

Nickel Titanium ◽

Control Group ◽

Heat Treated ◽

Respective Control Group ◽

Before And After ◽

Number Of Cycles ◽

The Impact

Peracetic acid (PAA) is widely used as a sterilizing/disinfecting agent, and, in endodontics, it has been introduced as a promising irrigant in root canal treatment. It has been used at different concentrations to achieve various functions. However, endodontic instruments in contact with PAA of a certain concentration may affect their fatigue resistance. Therefore, the aim of this study was to investigate the impact of PAA on the cyclic fatigue resistance of three commercial heat-treated nickel-titanium (NiTi) rotary files. Three types of heat-treated NiTi rotary files were selected: One Curve (OC), ProTaper Gold (PTG), and Wave One Gold (WOG). Each type was divided into three subgroups (n = 6 for each file type): (1) untreated instruments; (2) files immersed in 0.002% PAA; and (3) files immersed in 0.35% PAA. The performance of each file type was tested in a simulated canal. The number of cycles to fracture (NCF) was determined to assess cyclic fatigue resistance of the files. Independent sample t-test was applied to compare each treated file within a subgroup with its respective control group, and one-way ANOVA was used for comparison among the main groups. All types of tested files revealed a significant decline in the cyclic fatigue resistance after exposure to 0.002% PAA except the PTG ( P = 0.209 ). After exposure of the files to a higher concentration (0.35% PAA), a dramatic reduction was demonstrated by all the groups. Before and after exposure of the files to PAA, PTG displayed the highest cyclic fatigue resistance, followed by the WOG, while the OC showed the lowest resistance. Exposure of heated-treated NiTi files to PAA in a relatively high or low concentration adversely affects the cyclic fatigue resistance. The PTG files demonstrated the best performance among the tested types and can be disinfected with 0.002% PAA for clinical purpose.

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Effect of Cryogenic Treatment on Cyclic Fatigue of Nickel-titanium Rotary Files

10.21203/rs.3.rs-743019/v1 ◽

2021 ◽

Author(s):

Hamed Karkehabadi ◽

Abbas Farmani ◽

Zahra Pakseresht ◽

Faraz Sedaghat ◽

Saber Yavari Niya

Keyword(s):

Fatigue Resistance ◽

Room Temperature ◽

Cryogenic Treatment ◽

Cyclic Fatigue ◽

Nickel Titanium ◽

Warm Up ◽

Gutta Percha ◽

The Mean ◽

Time To Fracture

Abstract Objective: This study sought to assess the effect of cryogenic treatment on cyclic fatigue of Neoniti and Reciproc nickel-titanium (NiTi) rotary files. This in vitro, experimental study was performed on 48 Neoniti and Reciproc NiTi rotary files (#25, 6% taper) in two subgroups with and without cryogenic treatment. The files in cryogenic subgroups were stored in liquid nitrogen chamber at -196°C for 24 h. Next, they were placed at room temperature (25°C) to gradually warm up. Stainless steel (SS) blocks were used to standardize the degree of rotation of the files. The SS blocks simulated a root canal with the negative pattern of gutta-percha with 0.08 taper, #25 tip size, and 45° canal curvature. Each endodontic file was rotated in this canal until fracture. The time until fracture was recorded by a digital chronometer. Time to fracture was used to calculate the number of rotations before file fracture as the cyclic fatigue scale. Results: The mean cyclic fatigue resistance of both Neoniti and Reciproc rotary files in cryogenic subgroups was significantly higher than that in non-cryogenic control subgroups (P<0.05). Cryogenic treatment can significantly increase the cyclic fatigue resistance of Neoniti and Reciproc NiTi rotary files.

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Effect of deep cryogenic treatment on cyclic fatigue resistance of controlled memory wire nickel-titanium rotary instruments

Dental Research Journal ◽

10.4103/1735-3327.292069 ◽

2020 ◽

Vol 17 (4) ◽

pp. 300

Author(s):

Yazdan Sabet ◽

Samira Shahsiah ◽

Mohammad Yazdizadeh ◽

Sana Baghamorady ◽

Mansour Jafarzadeh

Keyword(s):

Fatigue Resistance ◽

Cryogenic Treatment ◽

Cyclic Fatigue ◽

Nickel Titanium ◽

Deep Cryogenic Treatment ◽

Rotary Instruments

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Effect of Electropolishing ProFile Nickel–Titanium Rotary Instruments on Cyclic Fatigue Resistance, Torsional Resistance, and Cutting Efficiency

Journal of Endodontics ◽

10.1016/j.joen.2007.10.007 ◽

2008 ◽

Vol 34 (2) ◽

pp. 190-193 ◽

Cited By ~ 52

Author(s):

Tung B. Bui ◽

John C. Mitchell ◽

J. Craig Baumgartner

Keyword(s):

Fatigue Resistance ◽

Cyclic Fatigue ◽

Nickel Titanium ◽

Cutting Efficiency ◽

Torsional Resistance ◽

Rotary Instruments

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The Effect of Multiple Autoclave Sterilization on the Cyclic Fatigue of Three Heat-Treated Nickel-Titanium Rotary Files: EdgeFile X7, Vortex Blue, and TRUShape

BioMed Research International ◽

10.1155/2020/8826069 ◽

2020 ◽

Vol 2020 ◽

pp. 1-6

Author(s):

Reham Sharroufna ◽

Mohammed Mashyakhy

Keyword(s):

Fatigue Resistance ◽

Cyclic Fatigue ◽

Nickel Titanium ◽

The Other ◽

Heat Treated ◽

Significant Difference ◽

The Mean ◽

Vortex Blue ◽

Number Of Cycles ◽

Cycles To Failure

Objective. The purpose of this study was to evaluate the effect of repeated autoclave sterilization on the cyclic fatigue resistance of heat-treated NiTi rotary endodontic instruments. Materials and Methods. Three NiTi rotary endodontic instruments (EdgeFile X7, EFX7 0.30/0.4; Vortex Blue, VB 0.30/0.4; and TRUShape, TS 0.30/0.6) were selected. Each group ( n = 24 each) was divided into 2 subgroups ( n = 12 each): sterilized instruments and nonsterilized instruments. The sterilized instruments were subjected to 10 cycles of autoclave sterilization. Twelve instruments from each different subgroups were tested for cyclic fatigue resistance, and the number of cycles to failure (NCF) was calculated. Means and standard deviations were calculated for each group, and data were statistically analyzed using the SPSS program ( P < 0.05 ). Results. Sterilized and nonsterilized EFX7 files showed the highest NCF compared with other file subgroups. Comparing the results between sterilized and nonsterilized instruments for each type of files, there was a statistically significant difference ( P < 0.05 ) only between sterilized and nonsterilized EFX7 files (1198 versus 755 NCF). The other instruments did not show significant differences ( P > 0.05 ) in the mean NCF as a result of sterilization cycles (VB, 606 versus 568 NCF; TS, 487 versus 442 NCF). Conclusion. Repeated cycles of autoclave sterilization increased the NCF of the new heat-treated files, with EFX7 showing statistically significant superior results compared with other files tested.

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Effect of Hydrogen Peroxide on Cyclic Fatigue Resistance of NiTi Endodontic Files

Journal of The Pakistan Dental Association ◽

10.25301/jpda.294.246 ◽

2020 ◽

Vol 29 (04) ◽

pp. 246-248

Author(s):

Huma Sarwar ◽

◽

Meshal M Meshal M Naeem ◽

Sumaiya Shabbir ◽

Sania Riaz ◽

...

Keyword(s):

Hydrogen Peroxide ◽

Fatigue Resistance ◽

Cyclic Fatigue ◽

Nickel Titanium ◽

Resistance Testing ◽

P Value ◽

Group I ◽

Significant Difference ◽

Group Ii ◽

Dent Assoc

OBJECTIVE: To investigate the effect of nickel titanium rotary endodontic file immersion in hydrogen peroxide on cyclic fatigue resistance. METHODOLOGY: Twenty Six Protaper Universal (Dentsply Maillerfier) F1 files were randomly divided into two experimental groups. In Group I, Protaper universal variable taper F1 files were immersed in normal saline where as in Group II, the files were soaked in hydrogen peroxide (6% w/v) for 2 hours at 37°C. Cyclic fatigue of each file was checked by recording the number of rotations required to break a file in a 90°curve with a 5 mm radius. For statistical analysis of data, Two-way ANOVA was applied. A p value of <0.05 was considered significant. RESULT: Out of Twenty Six, Six files fractured spontaneously after immersion in hydrogen peroxide. Twenty files were subjected to fracture resistance testing. Statistically significant difference in cyclic fatigue resistace between the two groups was found (p=0.002). The files soaked in Group II required less revolutions to fracture than the ones immersed Group I. CONCLUSION: The immersion of NiTi endodontic files in hydrogen peroxide significantly reduces cyclic fatigue resistance. Therefore, immersion of the NiTi endodontic files in hydrogen peroxide solution for removal of clogged debris should be discouraged. KEYWORDS: Cyclic fatigue, Endodontic instruments, Hydrogen peroxide, NiTi HOW TO CITE: Sarwar H, Naeem MM, Shabbir S, Riaz S, Afaq H, Shabbir J. Effect of hydrogen peroxide on cyclic fatigue resistance of NiTi endodontic files. J Pak Dent Assoc 2020;29(4):246-248.

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