Comparison of the cyclic fatigue resistance of WaveOne Gold, Reciproc Blue, and 2Shape NiTi systems in the root canal manipulation (original) (raw)
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Restorative Dentistry & Endodontics
Objectives: To compare the flexural cyclic fatigue resistance and the length of the fractured segments (FLs) of recently introduced M-Pro rotary files with that of RaCe rotary files in curved canals and to evaluate the fracture surface by scanning electron microscopy (SEM). Materials and Methods: Thirty-six endodontic files with the same tip size and taper (size 25, 0.06 taper) were used. The samples were classified into 2 groups (n = 18): the M-Pro group (M-Pro IMD) and the RaCe group (FKG). A custom-made simulated canal model was fabricated to evaluate the total number of cycles to failure and the FL. SEM was used to examine the fracture surfaces of the fragmented segments. The data were statistically analyzed and comparisons between the 2 groups for normally distributed numerical variables were carried out using the independent Student's t-test. A p value less than 0.05 was considered to indicate statistical significance. Results: The M-Pro group showed significantly higher resistance to flexural cyclic fatigue than the RaCe group (p < 0.05), but there was no significant difference in the FLs between the 2 groups (p ≥ 0.05). Conclusions: Thermal treatment of nickel-titanium instruments can improve the flexural cyclic fatigue resistance of rotary endodontic files, and the M-Pro rotary system seems to be a promising rotary endodontic file.
The Journal of Contemporary Dental Practice, 2020
Aim: The aim of the present study is twofold: to evaluate cyclic fatigue resistance differences of two different nickel-titanium rotary instruments, brand new and after an ex vivo instrumentation of single root extracted teeth. Materials and methods: Twenty new S One 20.06 were randomly divided into two groups. The first group (n = 10) was immediately subjected to a cyclic fatigue test (S One Group I). The second group (n = 10) (S one Group II) performed a cyclic fatigue test after three ex vivo root canal treatment with a single-file technique. The same process has been carried out for 20 M-Two 20.06 instruments. Results: Mean time to fracture (TtF) for Group I was 51.14 ± 1.28 for S One and 32.62 ± 0.17 for M-Two 20.06 and for Group II was 46.00 ± 0.99 for S One and 27.75 ± 1.58 for M-Two 20.06. The reduction in TtF values from Group I to Group II was 11% for S One and 15% for M-Two. Statistical analysis found significant differences in all the groups examined (p value < 0.05). Mean fragment length (FL) for Group I was 3.07 ± 0.17 for S One and 3.05 ± 0.14 for M-Two 20.06 and for Group II was 3.05 ± 0.07 for S One and 3.05 ± 0.14 for M-Two 20.06. Statistical analysis was pursued, and no significant difference was found (p value > 0.05). Conclusion: The S-One showed significantly more resistance to cyclic fatigue stress than M-Two for both new and used instruments. This validates the hypothesis that the AF H wire enables the S One files to endure more the cyclic fatigue stresses. Clinical significance: This study demonstrates the cyclic fatigue resistance of a new endodontic instrument after repetitive usage.
Survival Analysis of Factors Influencing Cyclic Fatigue of Nickel-Titanium Endodontic Instruments
Advances in Materials Science and Engineering, 2015
Objective. The aim of this study was to validate a survival analysis assessing the effect of type of rotary system, canal curvature, and instrument size on cyclic resistance.Materials and Methods. Cyclic fatigue testing was carried out in stainless steel artificial canals with radii of curvature of 3 or 5 mm and the angle of curvature of 60 degrees. All the instruments were new and 25 mm in working length, and ISO colour coding indicated the instrument size (yellow for size 20; red for size 25).Wizard Navigatorinstruments,Mtwoinstruments,ProTaperinstruments, andRevo-Sinstruments were passively rotated at 250 rotations per minute, and the time fracture was being recorded. Subsequently, fractographic analysis of broken tips was performed by scanning electron microscope. The data were then analysed by the Kaplan-Meier estimator of the survival function, the Cox proportional hazards model, the Wald test for regression covariates, and the Wald test for significance of regression model.Co...
An In Vitro Cyclic Fatigue Analysis of Different Endodontic Nickel-Titanium Rotary Instruments
Journal of Endodontics, 2012
Introduction: The study compared Twisted File (TF) with 3 traditionally manufactured systems to determine whether changes in the manufacturing process improved the cyclic fatigue resistance. Methods: Four rotary file systems, (1) ProFile (PF), (2) Mtwo, (3) K3, and (4) TF, were tested in artificial canals with 45 and 90 angles of curvature. Ten instruments each of the 4 file systems were tested in both angles of curvature (n = 10). All instruments had identical size and taper (.06/0.25 tip diameter). Results: A statistically significant difference (P < .05) was noted between TF and other nickel-titanium instruments in both 45 and 90 angles of curvature. TF showed the greatest mean number of cycles to failure. There was no statistical difference between PF and K3 (P > .05) in both canal curvatures; however, statistically significant difference (P < .05) was observed between Mtwo and the other 2 traditionally manufactured instruments. Mtwo showed the lowest mean number of cycles to failure. Conclusions: Under the conditions of this study, size .06/0.25 TF was significantly more resistant to fatigue than the other 3 instrument systems produced with the traditional grinding process.
Aim: To compare cyclic fatigue resistance of Protaper Gold and Hyflex EDM Nickel Titanium rotary endodontic files used in root canals with 30 0 ,60 0 and 90 0 angulations and 2mm radius of curvature Materials and Methods: 39 new NiTi instruments from each group were subjected to cyclic fatigue tests in simulated root canals with 30, 60 and 90 degrees curvatures (n=13) in each sub group. Custom made jig was made and the instruments were rotated according to manufactures recommendations. The time taken to fracture was recorded and numbers of cycles to fracture were calculated. All data was subjected to statistical analysis using Mann Whitney U test. For repeated measures Friedman test was used.SEM analysis was done to evaluate type of fracture. Results: Hyflex EDM showed a significant increase in cyclic fatigue p<0.05) than Protaper Gold. Conclusion: Hyflex EDM files had significantly higher cyclic fatigue resistance than Protaper Gold files.
Oral Surgery, Oral Medicine, Oral Pathology, Oral Radiology, and Endodontology, 2011
Objectives. This study evaluated the effects of curvature location along an artificial canal on cyclic fatigue (CF) of an Mtwo rotary instrument, verifying the number of cycles to fatigue fracture (NCF) and morphologic characteristics of the fractured instruments. Study design. CF testing of instruments was performed in artificial canals with curvature radii of 10 mm and arc lengths of 11 mm. Mtwo rotary instruments size 40, 0.04 taper were used in 2 groups (n ϭ 10): group A, curvature positioned on middle part; group B, apical curvature. All instruments were rotated until fracture. The number of cycles to failure was registered. Data were analyzed by independent sample t test. Fractured surfaces and the helical shafts of the instruments were analyzed by scanning electron microscopy. Results. NCF for groups A and B had significant statistic differences (P Ͻ .05). The highest values were found in the group where the curvature was positioned on the apical part of the canal. No plastic deformation was observed on the helical shafts. Conclusions. The number of cycles to fracture of the Mtwo instruments increased when the arc was changed from the middle to the apical part of the canal. The morphologic characteristics of the fractured surfaces were of the ductile type.
Predicting in vivo failure of rotary nickel-titanium endodontic instruments under cyclic fatigue
Dental Materials Journal, 2012
The aim of this study was to examine the lifespan or number of cycles to failure of tapered rotary nickel-titanium (Ni-Ti) endodontic instruments. Simulated root canals with different curvatures were used to determine a relation between canal curvature and instrument lifespan. Using a novel mathematical model for the deformation of pseudoelastic Ni-Ti alloy, it was shown that maximum stress need not necessarily occur at the outer layer. On the basis of this observation, the Coffi n-Manson relation was modifi ed with parameters determined from this experiment. Results showed that the number of cycles to failure was infl uenced by the angle and radius of canal curvature and the size of instrument at the beginning of canal curvature. The resulting quantitative mathematical relation could be used to predict the lifespan of rotary Ni-Ti endodontic instruments under clinical conditions and thereby reduce the incidence of instrument failure in vivo.