Combining apical torsional load and cyclic fatigue resistance of NiTi instruments: New approach to determine the effective lifespan of rotary instruments

2021 ◽  
Author(s):  
Francesco Iacono ◽  
Chiara Pirani ◽  
Maria Rosaria Gatto ◽  
Carlo Prati ◽  
Ove A. Peters
Keyword(s):  
Fatigue Resistance ◽  
Cyclic Fatigue ◽  
New Approach ◽  
Torsional Load ◽  
Rotary Instruments ◽  
Niti Instruments

scholarly journals Cyclic fatigue resistance of reduced-taper nickel-titanium (NiTi)instruments in doubled-curved (S-shaped) canals at body temperature

2020 ◽  
Vol 14 (2) ◽  
pp. 111-115 ◽  
Author(s):  
Gülsah Uslu ◽  
Mustafa Gündoğar ◽  
Taha Özyürek ◽  
Gianluca Plotino
Keyword(s):  
Fatigue Resistance ◽  
Fatigue Testing ◽  
Cyclic Fatigue ◽  
Nickel Titanium ◽  
Clinical Environment ◽  
Root Canals ◽  
Rotary Instruments ◽  
Niti Instruments ◽  
Student’S T ◽  
Number Of Cycles

Background. This study was conducted to compare the cyclic fatigue resistance of VDW.ROTATE,TruNatomy Prime, HyFlex CM, and 2Shape nickel-titanium (NiTi) rotary instruments in doublecurvedcanals in a simulated clinical environment. Methods. Eighty NiTi files were used for the fatigue testing in stainless steel canals compatible withinstrument sizes until fracture occurred (n=20): VDW.ROTATE (04./25#), TruNatomy Prime (04./26#),HyFlex CM (04./25#) and 2Shape TS04./25#( 1). For each instrument, the number of cycles to fracture(NCF) was calculated, and the fractured fragment length (FL) was measured. To verify that the fileswere fractured due to cyclic fatigue, the fractured surfaces of the files were evaluated under a scanningelectron microscope. Data were statistically analyzed using the Kruskal–Wallis and Student’s t-tests atthe %95 confidence level. Results. The failure of the files due to cyclic fatigue was first seen in the apical curvature before thecoronal curvature (P<0.05). The highest fatigue resistance was observed in VDW.ROTATE and HyFlexCM files in both curvatures (P<0.05). There were no significant differences in the fatigue resistancebetween the HyFlex CM and VDW.ROTATE files or between the 2Shape and the TruNatomy files(P>0.05). There was no difference in the fractured lengths of the files between the apical and coronalcurvatures (P>0.05). Conclusion. In artificial S-shaped root canals, VDW.ROTATE and HyFlex CM files exhibited higherfatigue resistance compared to 2Shape and TruNatomy files.

scholarly journals Advancement of Mechanical Properties of Nickel-Titanium Rotary Endodontic Instruments by Spring Machining on the File Shaft

Materials ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5246
Author(s):  
Sangmi Ahn ◽  
Jung-Hong Ha ◽  
Sang Won Kwak ◽  
Hyeon-Cheol Kim
Keyword(s):  
Fatigue Resistance ◽  
Cyclic Fatigue ◽  
Nickel Titanium ◽  
Significance Level ◽  
Rotary Instruments ◽  
Niti Instruments ◽  
General Dentists ◽  
Niti Rotary Instruments ◽  
Distortion Angle ◽  
Paired T Test

Nickel-titanium (NiTi) endodontic rotary instruments are used extensively in root canal procedures by both general dentists and specialists. However, their vulnerability to fracture is the major reason for clinicians’ concern regarding their use. The objective of this study was to investigate the potential effects of spring machining of the file shaft on the fatigue and torsional resistances of NiTi rotary instruments. Three types of NiTi rotary systems with (S) and without (NS) spring machining were used in this study (n = 15 each): a spring file (SPR; #25/.06, SPR-S, SPR-NS), a ProTaper Next X2 (PTN; #25/variable taper, PTN-S, PTN-NS), and a ProTaper Gold F2 (PTG; #25/variable taper, PTG-S, PTG-NS). Spring machining was adjusted on the 6 mm of each file system’s shaft via a laser cutting process. The number of rotation cycles until fracture (i.e., cyclic fatigue resistance), ultimate torsional strength, the distortion angle, and the toughness of each subgroup were estimated with specially designed devices. The results were analyzed using a paired t-test at a significance level of 95%. NiTi rotary instruments with spring machining exhibited a higher cyclic fatigue resistance than instruments without spring machining. The groups with spring machining exhibited a higher toughness and larger distortion angle than the groups without it (p < 0.05). In conclusion, spring machining on the shank of NiTi instruments may provide a stress-bearing area and attenuate the torsional and cyclic fatigue of NiTi rotary instruments.

scholarly journals Effect of immersion in sodium hypochlorite on the cyclic fatigue resistance of three rotary instruments

2020 ◽  
Vol 23 (6) ◽  
pp. 554
Author(s):  
AnaGrasiela Da Silva Limoeiro ◽  
Daiane Nogueira ◽  
CarlosEduardo Da Silveira Bueno ◽  
AugustoShoji Kato ◽  
AlexandreSigrist De Martin ◽  
...  
Keyword(s):  
Fatigue Resistance ◽  
Sodium Hypochlorite ◽  
Cyclic Fatigue ◽  
Rotary Instruments

Influence of Kinematics on the Cyclic Fatigue Resistance of Replicalike and Original Brand Rotary Instruments

2020 ◽  
Vol 46 (8) ◽  
pp. 1136-1143 ◽  
Author(s):  
Jorge N.R. Martins ◽  
Emmanuel João Nogueira Leal Silva ◽  
Duarte Marques ◽  
António Ginjeira ◽  
Francisco Manuel Braz Fernandes ◽  
...  
Keyword(s):  
Fatigue Resistance ◽  
Cyclic Fatigue ◽  
Rotary Instruments

Response: Cyclic fatigue resistance of ProTaper Next nickel-titanium rotary instruments

2015 ◽  
Vol 48 (11) ◽  
pp. 1101-1101
Author(s):  
A. M. Elnaghy
Keyword(s):  
Fatigue Resistance ◽  
Cyclic Fatigue ◽  
Nickel Titanium ◽  
Rotary Instruments

scholarly journals Comparison of cyclic fatigue resistance of XP-endo Shaper, HyFlex CM, FlexMaster and Race instruments

2018 ◽  
Vol 12 (3) ◽  
pp. 208-212 ◽  
Author(s):  
Mehmet Adiguzel ◽  
Ipek Isken ◽  
Ismail Ilker Pamukcu
Keyword(s):  
Body Temperature ◽  
Fatigue Resistance ◽  
Cyclic Fatigue ◽  
Radius Of Curvature ◽  
Rotary Instruments ◽  
Recorded Data ◽  
The Difference ◽  
Number Of Cycles ◽  
Cycles To Failure ◽  
One Way Anova

Background. The aim of this study was to compare the cyclic fatigue resistance of XP-endo Shaper, HyFlex CM, FlexMaster and Race rotary instruments at body temperature (37±1°C). Methods. Twenty XP-endo Shaper (#30/.01), 20 HyFlex CM (#30/.04), 20 FlexMaster (#30/.04) and 20 Race (#30/.04) instruments were tested at body temperature (n=20). The instruments were evaluated in artificial canals with a 3-mm radius of curvature and 60° angle of curvature to the center of the 1.5-mm-wide canal. Each instrument was rotated until fracture occurred and the number of cycles to failure (NCF) recorded. Data were analyzed using one-way ANOVA and Tukey HSD tests (P<0.05). Results. The difference in the NCF of all the instruments was statistically significant (P<0.05). The order of the instruments from the highest to the lowest NCF was as follows: XP-endo Shaper (3064.0±248.1), HyFlex CM (1120.5±106.1), FlexMaster (569.8±48.4) and Race (445.5±53.5). Conclusion. Under the limitations of the present study, XP-endo Shaper instruments were more resistant to cyclic fatigue than the #30/.04 nickel-titanium rotary instruments immersed in water at simulated body temperature.

scholarly journals Comparison of cyclic fatigue resistance of novel NiTi rotary instruments with low taper angle

2021 ◽  
Vol 17 (3) ◽  
pp. 190-195
Author(s):  
Ahmet Demirhan Uygun ◽  
Yahya Güven ◽  
Mehmet Ünal
Keyword(s):  
Fatigue Resistance ◽  
Cyclic Fatigue ◽  
Taper Angle ◽  
Rotary Instruments ◽  
Niti Rotary Instruments

scholarly journals Role of the Flat-Designed Surface in Improving the Cyclic Fatigue Resistance of Endodontic NiTi Rotary Instruments

Materials ◽  
2019 ◽  
Vol 12 (16) ◽  
pp. 2523 ◽  
Author(s):  
Gianluca Gambarini ◽  
Gabriele Miccoli ◽  
Marco Seracchiani ◽  
Tatyana Khrenova ◽  
Orlando Donfrancesco ◽  
...  
Keyword(s):  
Cyclic Fatigue ◽  
Nickel Titanium ◽  
Segment Length ◽  
Flat Side ◽  
Heat Treated ◽  
Rotary Instruments ◽  
Time To Fracture ◽  
Niti Instruments ◽  
Niti Rotary Instruments

The aim of this study was to investigate the role of the flat-designed surface in improving the resistance to cyclic fatigue by comparing heat-treated F-One (Fanta Dental, Shanghai, China) nickel–titanium (NiTi) rotary instruments and similar prototypes, differing only by the absence of the flat side. The null hypothesis was that there were no differences between the two tested instruments in terms of cyclic fatigue lifespan. A total of 40 new NiTi instruments (20 F-One and 20 prototypes) were tested in the present study. The instruments were rotated with the same speed (500 rpm) and torque (2 N) using an endodontic motor (Elements Motor, Kerr, Orange, CA, USA) in the same stainless steel, artificial canal (90° angle of curvature and 5 mm radius). A Wilcoxon–Mann–Whitney test was performed to assess the differences in terms of time to fracture and the length of the fractured segment between the flat- and non-flat-sided instruments. Significance was set at p = 0.05. The differences in terms of time to fracture between non-flat and flat were statistically significant (p < 0.001). In addition, the differences in terms of fractured segment length were statistically significant (p = 0.034). The results of this study highlight the importance of flat-sided design in increasing the cyclic fatigue lifespan of NiTi rotary instruments.

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