Decrease in the fatigue resistance of nickel-titanium rotary instruments after clinical use in curved root canals

Bahia, Maria Guiomar de Azevedo; Buono, Vicente Tadeu Lopes

doi:10.1016/j.tripleo.2004.10.013

Cited by 130 publications

(156 citation statements)

References 14 publications

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“…However, there is no agreement about the exact number of uses that an instrument can be submitted to before failure (9). In some cases, the instruments should be discarded after a single use in very complex, calcified, and curved canals (10) or selectively discarded to increase safety in clinical practice (11). Therefore, the objective of this study was to evaluate the cyclic fatigue resistance in NiTi rotary endodontic instruments, using a custom-made cyclic fatigue testing apparatus.…”

Section: Introductionmentioning

confidence: 99%

Cyclic Fatigue Resistance of Rotary NiTi Instruments after Simulated Clinical Use in Curved Root Canals

2013

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The aim of this study was to assess cyclic fatigue resistance in rotary nickel-titanium instruments after simulated clinical use in curved root canals (40-degree, 5-mm radius curve). Thirty-six RaCe rotary NiTi files, size #5, taper 0.04, were divided into 3 groups: Groups A, B and C with one, three and five cycles of use, respectively. Time to failure was recorded with a stopwatch in seconds and subsequently converted to number of cycles to fracture. The data were analyzed statistically by ANOVA and Tukey's test (α=0.05). Five sets of clinically used files (group C) reached significantly lower cycle-numbers before fracture (mean=197.5 cycles) when compared with one set of clinically used files (mean=309.2) and three sets (mean=287.5). Results showed that the number of simulated clinical uses of RaCe instruments for shaping curved canals affects adversely the fatigue resistance of these instruments after five uses.

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Section: Introductionmentioning

confidence: 99%

Cyclic Fatigue Resistance of Rotary NiTi Instruments after Simulated Clinical Use in Curved Root Canals

2013

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“…However, the potential for fracture of these instruments is still a main concern associated with their use 2,3) . Root canal curvature 4) , instrument geometry 5,6) , working speed 7) , the use of irrigant 8) , torque and sterilization procedures 9,10) , metal surface treatments 11) , heat treatment 12) , metallurgic characterization of the NiTi alloys 13) , and repeated clinical use 14,15) are factors that might enhance instrument fatigue. Moreover, these factors show different effects on the lifespans of different NiTi instrument systems.…”

Section: Introductionmentioning

confidence: 99%

Deflecting load of nickel titanium rotary instruments during cyclic fatigue

et al. 2012

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The dispersion of the lifetime of NiTi instruments, and their deflecting load (DL) changes during cyclic fatigue were investigated. A total of 120 ProFile NiTi rotary instruments were tested using a specially designed cyclic fatigue testing apparatus with three pins. Using these pins, the instrument was bent and rotated at 300 rpm to fracture. DL was recorded using a load cell attached to the central pin. For each sample, the working time was converted to number of cycles to fracture (NCF) and the mean DL (DLm) was calculated. The averages of NCF and DLm of 120 samples were 584.3±180.5 cycles and 6.44±0.91 N, respectively. All samples showed a sequential decrease in DL during rotation. Based on the present study, it is impossible to estimate the lifetime of a NiTi instrument from NCF. Thus, the change in DL could be an alternative criterion to determine the remaining lifetime.

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“…7 This behavior allowed engine-driven NiTi endodontic instruments to be developed, which resulted in more efficient and safe root canal preparation with better preservation of the original canal shape. 8,9,10 Despite these favorable features, NiTi instruments are susceptible to fracture during use. This type of failure may occur unexpectedly, with no visual indication of plastic deformation on the instrument blade.…”

Section: Introductionmentioning

confidence: 99%

“…These new manufacturing processes aim to reduce the occurrence of instrument fracture and improve the mechanical properties of endodontic files, in comparison to those produced by machined conventional NiTi alloy. 9,16,18 Previous studies assessed some mechanical properties of TF, RaCe and Vortex instruments. 19,20 The aim of the present study was to extend these findings by assessing the mechanical behavior of three NiTi endodontic instruments with similar geometry, but produced by different manufacturing methods.…”

Section: Introductionmentioning

confidence: 99%

Flexibility and resistance to cyclic fatigue of instruments manufactured by different methods

Lopes¹,

Lopes²,

Elias³

et al. 2015

Dental Press Endod

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Decrease in the fatigue resistance of nickel-titanium rotary instruments after clinical use in curved root canals

Cited by 130 publications

References 14 publications

Cyclic Fatigue Resistance of Rotary NiTi Instruments after Simulated Clinical Use in Curved Root Canals

Cyclic Fatigue Resistance of Rotary NiTi Instruments after Simulated Clinical Use in Curved Root Canals

Deflecting load of nickel titanium rotary instruments during cyclic fatigue

Flexibility and resistance to cyclic fatigue of instruments manufactured by different methods

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