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

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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Safety and Effectiveness of Additional Apical Preparation using a Rotary Heat-treated Nickel–Titanium file with Larger Diameter and Minimum Taper in Retreatment of Curved Root Canals

European Journal of Dentistry ◽

10.1055/s-0041-1723065 ◽

2021 ◽

Author(s):

Jader Camilo Pinto ◽

Fernanda Ferrari Esteves Torres ◽

Airton Oliveira Santos-Junior ◽

Marco Antonio Hungaro Duarte ◽

Juliane Maria Guerreiro-Tanomaru ◽

...

Keyword(s):

Fatigue Resistance ◽

Continuous Wave ◽

Cyclic Fatigue ◽

Nickel Titanium ◽

Filling Material ◽

Root Canals ◽

Filling Materials ◽

Heat Treated ◽

Before And After ◽

Curved Root Canals

Abstract Objective The aim of this study was to investigate the effect of additional apical preparation using the ProDesign Logic (PDL) 50/.01 rotary heat-treated nickel–titanium (NiTi) file with a larger diameter and minimal taper for retreatment of curved root canals. Materials and Methods Mesial curved root canals of 12 mandibular molars were prepared using PDL 25/.06 and filled using the continuous wave of condensation technique and AH Plus sealer. After retreatment using ProDesign S (PDS) 25/.08, PDL 25/.06 and PDL 35/05, a complementary procedure was performed with PDL 50/.01. Microcomputed tomography (micro-CT) scanning was performed before and after retreatment procedures. The cyclic fatigue resistance of unused PDS 25/.08, PDL 25/.06, PDL 35/.05 and PDL 50/.01 instruments (n = 12) was evaluated in a stainless-steel device. Statistical Analysis Data on the volumes of the root canals and the remaining filling materials were submitted to the paired t-test. Cyclic fatigue resistance data was submitted to one-way ANOVA and Tukey’s tests (α = 0.05). Results Use of PDL 50/.01 decreased the remaining filling materials in the apical third (p < 0.05). The root canal volume was similar in the cervical and middle thirds before and after preparation using PDL 50/.01 (p > 0.05). PDL 50/.01 presented the highest cyclic fatigue resistance (p < 0.05). Conclusions Use of the PDL 50/.01 instrument as an additional apical preparation for retreatment of curved root canals improved filling material removal in the apical third, while maintaining the dentin in the cervical and middle thirds. In addition, PDL 50/.01 presented high-flexural resistance.

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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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Effects of continuous irrigation at room temperature or +4ºC on the cyclic fatigue resistance of K3XF instruments

Journal of Dental Research Dental Clinics Dental Prospects ◽

10.34172/joddd.2020.038 ◽

2020 ◽

Vol 14 (3) ◽

pp. 153-157

Author(s):

Hakan Arslan ◽

Ezgi Doğanay Yıldız ◽

Gizem Taş ◽

Ertuğrul Karataş ◽

Ebru Tepecik

Keyword(s):

Fatigue Resistance ◽

Room Temperature ◽

Saline Solution ◽

Cyclic Fatigue ◽

Control Group ◽

Continuous Irrigation ◽

Double Curvature ◽

Niti Instruments ◽

Number Of Cycles ◽

The Impact

Background. The present study aimed to evaluate the impact of continuous irrigation with saline solution at room temperature or +4°C on the cyclic fatigue resistance of K3XF files. Methods. Forty-eight new K3XF files (#30, .04 taper) were randomly assigned to three groups: control group (no irrigation), continuous irrigation with saline solution at room temperature, and continuous irrigation with saline solution at +4°C. The instruments were tested in an artificial, stainless steel root canal with a double curvature at body temperature (37±1°C). Time to fracture was converted to the number of cycles to fracture (NCF). The lengths of the fractured fragments were recorded. Kruskal–Wallis H test and one-way ANOVA were used to analyze data. Results. K3XF files’ cyclic fatigue resistance was significantly higher in the continuous irrigation groups than in the control group. Continuous irrigation with saline solution at +4°C resulted in higher cyclic fatigue resistance than continuous irrigation with saline solution at room temperature. There were no significant differences between the groups in terms of the fractured fragments’ length. Conclusion. Within this study’s limitations, continuous irrigation with saline solution increased the NCF of NiTi instruments; decreasing the saline solution’s temperature increased this effect.

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

Materials ◽

10.3390/ma13245823 ◽

2020 ◽

Vol 13 (24) ◽

pp. 5823

Author(s):

Saulius Drukteinis ◽

Vytaute Peciuliene ◽

Ruta Bendinskaite ◽

Vilma Brukiene ◽

Rasmute Maneliene ◽

...

Keyword(s):

Fatigue Resistance ◽

Cyclic Fatigue ◽

Fractographic Analysis ◽

Significance Level ◽

Root Canals ◽

Topographic Features ◽

New Instrument ◽

Before And After ◽

Number Of Cycles ◽

Thermally Treated

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

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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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Effect of Core Mass and Alloy on Cyclic Fatigue Resistance of Different Nickel-Titanium Endodontic Instruments in Matching Artificial Canals

Materials ◽

10.3390/ma14195734 ◽

2021 ◽

Vol 14 (19) ◽

pp. 5734

Author(s):

Sebastian Bürklein ◽

Lennart Zupanc ◽

David Donnermeyer ◽

Karsten Tegtmeyer ◽

Edgar Schäfer

Keyword(s):

Fatigue Resistance ◽

Cyclic Fatigue ◽

Nickel Titanium ◽

The Other ◽

Design Parameters ◽

Core Mass ◽

Cross Sectional ◽

Significance Level ◽

Cross Sectional Design ◽

The Impact

Instrument failure during root canal preparation is still a concern among endodontists. However, it remains unclear whether the use of more martensitic alloys or the cross-sectional design parameters (i.e., core mass) significantly improve fracture resistance. The aim of the study was to evaluate the impact of core mass and alloy on dynamic cyclic fatigue resistance of nickel-titanium endodontic instruments in matching artificial canals at body temperature. Two groups were tested. (A) taper 0.04: F360 (Komet, Lemgo, Germany), Twisted file (Sybron Endo, Glendora, CA, USA) (=TF), JIZAI (Mani, Tochigi, Japan) (=J_04) (all size #25) and the variable tapered TruNatomy (Dentsply, Ballaigues, Switzerland) (size #26) (=TN). (B) size #25; taper 0.06: (Mtwo (VDW, Munich, Germany), JIZAI (Mani) (=J_06), and variable tapered Hyflex EDM OneFile (Coltene Whaledent, Altstätten, Switzerland) (=HF). Time, number of cycles to fracture (NCF), and number and length of fractured fragments were recorded and statistically analysed using ANOVA Student-Newman-Keuls, Kruskal–Wallis or Chi-square test (significance level = 0.05). (A) TN showed the significantly shortest time until fracture, followed by TF, F360 and J_04 which also differed significantly, while NCF showed the following order: F360 < TN < TF < J_04 (p < 0.05). Only one J_04 but all instruments of the other groups fractured within the test-limit of 10 min. (B) Mtwo was significantly inferior concerning time until fracture and NCF, compared to J_06 and HF (p < 0.05), which did not differ significantly (p > 0.05). While all Mtwo instruments fractured, only four instruments failed in the other groups (p < 0.05). Within the limitations of this study, alloy and cross-sectional design (i.e., core mass) were critical factors regarding instrument failure, but none of these factors could be determined as a main parameter for increased or decreased time, and cycles to fracture. Rather, it seemed to be the interaction of multiple factors (e.g., longitudinal and cross-sectional design, alloy, and rotational speed) that was responsible for differences in the time and cycles to fracture. Nonetheless, all instruments had lifetimes that allow safe clinical use. However, the superiority or inferiority of an instrument with regard to cyclic fatigue based on laboratory results—even when identical trajectories are guaranteed—may be considered questionable, as the characteristics and design parameters of the instruments vary considerably, and the experimental setups lack additional clinical parameters and thus clinical relevance.

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Influence of Different Heat Treatments on Torsional and Cyclic Fatigue Resistance of Nickel–Titanium Rotary Files: A Comparative Study

Applied Sciences ◽

10.3390/app10165604 ◽

2020 ◽

Vol 10 (16) ◽

pp. 5604 ◽

Cited By ~ 2

Author(s):

Gianluca Gambarini ◽

Andrea Cicconetti ◽

Dario Di Nardo ◽

Gabriele Miccoli ◽

Alessio Zanza ◽

...

Keyword(s):

Heat Treatment ◽

Fatigue Resistance ◽

Cyclic Fatigue ◽

Sem Analysis ◽

Nickel Titanium ◽

Torsional Resistance ◽

Heat Treated ◽

Torsional Test ◽

Time To Fracture ◽

Flexural Resistance

Protaper Universal (PTU), Protaper Gold (PTG) (Maillefer, Ballaigues, CH), EdgeTaper (ET), and EdgeTaper Platinum (ETP) (Albuquerque, NM, USA) were tested for both torsional and flexural resistance. The aim of the present study was to evaluate the influence of proprietary heat treatment on the metallurgical properties of the aforementioned instruments. Four groups of 30 different instruments (size 20.07) were tested, then divided into two subgroups of 15 instruments—one for the cyclic fatigue test in a curved canal (90°—2 mm radius) at 300 rpm and 2.5 Ncm. The time to fracture (TtF) and fragment length (FL) were recorded. The other subgroup was subjected to the torsional test (300 rpm, 5.5 Ncm). The torque to fracture and TtF were recorded. All the instruments underwent a SEM analysis. The heat-treated instruments showed a significantly higher fatigue resistance than the non-heat-treated instruments (p < 0.05). No significant differences were found in the torsional resistance between the ET and PTU, and the ETP and PTG. However, when comparing all the groups, the heat-treated instruments showed less torsional resistance. The improvement from heat treatment was mainly found in the cyclic fatigue resistance.

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Resistance to Cyclic Fatigue of Nickel-Titanium Files Immersed in Sodium Hypochlorite at Body Temperature

International Journal of Dentistry ◽

10.1155/2020/8830163 ◽

2020 ◽

Vol 2020 ◽

pp. 1-5

Author(s):

Hind F. Abuhulaibah ◽

Ammar AbuMostafa

Keyword(s):

Stainless Steel ◽

Body Temperature ◽

Sodium Hypochlorite ◽

Cyclic Fatigue ◽

Nickel Titanium ◽

Control Group ◽

Significant Drop ◽

Number Of Cycles ◽

Post Hoc ◽

One Way Anova

Background/purpose. To assess the resistance to cyclic fatigue (CF) displayed by two nickel-titanium (NiTi) files, One Curve (OC) and ProTaper Gold (PTG), after their immersion in 2.5% sodium hypochlorite (NaOCl) solution at body temperature. Materials and Methods. Forty-five files from each brand were randomly assigned to three groups (n = 15) and subjected to the following: no immersion (control), 1-minute immersion, and 5-minute immersion in 2.5% NaOCl at 37°C. CF for all the files was tested within a well-lubricated stainless-steel artificial canal in a water bath at 37°C simulating body temperature. The procedure was video recorded, and the number of cycles to fracture (NCF) was calculated by multiplying the time taken to fracture, with the number of rotations per second. The data were analyzed for normality, and thereafter, one-way ANOVA with multiple Bonferroni was used as the post hoc test. Results. The resistance to CF of OC files was significantly higher than PTG files in all groups. In groups immersed in NaOCl for one minute, OC files showed significant drop in the CF resistance; PTG files showed a drop as well but not significantly. Both files demonstrated a significant drop in resistance to CF after immersion in NaOCl for five minutes compared to the control group. Conclusion. OC files were significantly more resistant to CF compared to PTG in all groups. Immersion in 2.5% NaOCl for 5 minutes significantly reduced the resistance to CF for all the files.

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Comparison of Cyclic Fatigue Resistance of Heat-Treated Nickel-Titanium Reciprocating Instruments at the Intracanal Temperature

Balkan Journal of Dental Medicine ◽

10.2478/bjdm-2021-0014 ◽

2021 ◽

Vol 25 (2) ◽

pp. 87-91

Author(s):

Neslihan Büşra Keskin ◽

Gürkan Güneç

Keyword(s):

Fatigue Resistance ◽

Cyclic Fatigue ◽

Radius Of Curvature ◽

Heat Treated ◽

Significant Difference ◽

Number Of Cycles ◽

The Moment ◽

The One ◽

Post Hoc ◽

Different Characteristics

Summary Background/Aim: The aim of the present study was to compare the cyclic fatigue resistance of NiTi files running with reciprocal motion and having different characteristics (RPC Blue, WOG, EndoArt Wise Reciproc Gold, EndoArt Wise Reciproc Blue) at the intracanal temperature (35°C) by using NaOCl irrigation solution. Material and Methods: Totally 60 WaveOne GOLD (Dentsply-Sirona, Ballaigues, Switzerland), Reciproc Blue (VDW, Munich, Germany), EndoArt Wise Reciproc Gold, and EndoArt Wise Blue (Inci Dental Productions Co, Istanbul, Turkey) (n= 15) files were used. Each of the rotary files were tested at the intracanal temperature (35°C) using a dynamic model in a stainless-steel artificial canal with an inner diameter of 1.5 mm, 60° angle of curvature, and 2mm radius of curvature until fracture occurred. The device automatically stopped at the moment of fracture and the number of cycles to the fracture was calculated as per second. The lengths of fractured parts were measured using a digital microcaliper. The One-Way Analysis of Variance (ANOVA) and Tukey’s post-hoc tests were used for intergroup comparisons. Results: In 2 mm Radius of curvature, the EndoArt Wise Reciproc Blue group had a significantly higher time to fracture followed by the EndoArt Wise Reciproc Gold, Resiproc Blue, WaveOne Gold. No significant difference was found between EndoArt Wise Reciproc Gold and Resiproc Blue groups (P>0.05). Among the groups, there was no statistically significant difference in the lengths of fractured parts of the instruments (P> 0.05). Conclusions: EndoArt Wise Reciproc Blue files exhibited significantly higher cyclic fatigue resistance compared with other files tested in a 2-mm radius of curvature and a 60° angle in an artificial canal at the intracanal temperature.

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