A comparison of cyclic fatigue between used and new Mtwo Ni–Ti rotary instruments (original) (raw)
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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.
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.
Australian Endodontic Journal, 2010
The fracture of nickel‐titanium rotary instruments is a serious problem that can jeopardise the outcome of root canal treatment. The aim of this study was to compare the cyclic fatigue resistance of new and used Mtwo rotary nickel‐titanium instruments in artificial canals with two different radii of curvature. Four hundred and twenty Mtwo instruments were used in the present study. Thirty new and 30 used instruments of each size were tested for cyclic fatigue in artificial canals with radii of curvature of 5 or 10 mm. Each instrument was rotated until fracture occurred and the number of cycles to fracture was calculated by multiplying time to fracture and rotational speed. Data were analysed using a t‐test. According to the results of the study, radius of curvature was an important factor on cyclic fatigue resistance and clinical use significantly reduced the instrument lifespan.
Influence of a brushing working motion on the fatigue life of NiTi rotary instruments
International Endodontic Journal, 2007
Plotino G, Grande NM, Sorci E, Malagnino VA, Somma F. Influence of a brushing working motion on the fatigue life of NiTi rotary instruments. International Endodontic Journal, 40, 45-51, 2007. Aim To evaluate the cyclic fatigue resistance of Mtwo NiTi rotary instruments when used with a brushing or no-brushing action in oval root canals. Methodology Cyclic fatigue testing of instruments was performed in tapered artificial canals with a 5 mm radius of curvature and an angle of curvature of 60°. Twenty Mtwo instruments for each size were selected and divided into two groups: group A ¼ 10 instruments used with a no-brushing motion (control group); group B ¼ 10 instruments used with a brushingmilling action. Each Mtwo instrument was used for cleaning and shaping 10 oval root canals. In all 80 instruments were rotated until fracture occurred and the number of cycles to failure (NCF) recorded. Data were analysed by one-way anova, Tukey HSD test and independent sample t-test to determine any statistical difference; the significance was determined at the 95% confidence level. Results No statistically significant reduction of NCF between instruments used with a no-brushing motion (group A) and instruments used with a brushing motion (group B) were apparent except for size 25, 0.06 taper. Mtwo size 10, 0.04 taper, size 15, 0.05 taper, size 20, 0.06 taper, size 25, 0.06 taper instruments had a decrease in life span of 1%, 0.5%, 8% and 19%, respectively. Conclusions Fatigue life of instruments of larger size could be reduced by using them with a lateral brushing or pressing movement. However, each file was successfully operated without intracanal failure, demonstrating that Mtwo rotary instruments can be used safely in a brushing action in simulated clinical conditions up to 10 times in oval canals.
Journal of critical reviews, 2020
Introduction: To compare the cyclic fatigue of resistance of WaveOne (WO; Dentsply Maillefer, Ballaigues, Switzerland) and WaveOne Gold (WOG, Dentsply Maillefer) small, primary, and large instruments in simulated root canals. Each instrument was rotated until fracture occurred. Methods: One hundred twenty nickel-titanium endodontic instruments were tested in two different curved artificial canals with different angles and radii of curvatures. WO and WOG small, primary, and large instruments were evaluated (n = 10 for each curvature). Each instrument was rotated until fracture occurred. The time to failure was recorded, and the length of the fractured tip was measured. An independent Student't test was used to compare the means between the 2 groups. Oneway analysis of variance and Tukey' post hoc tests were used for multiple comparisons (P < .05). Results: At all the sizes tested and both curvatures, the cyclic fatigue resistance of the WOG instruments was higher than that of the WO instruments of corresponding sizes (P < .001). The WOG instruments were approximately twice as resistant to failure as the WO instruments were at a 60 angle of curvature, whereas the WOG instruments were 3 times more resistant at a 90 angle of curvature. The length of the fractured part of the instruments was similar among all the groups (P > .05). Conclusions: Within the limitations of this study, WOG instruments were more resistant to cyclic fatigue than WO instruments.
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 fracture of instruments within root canal during endodontic treatment is a common incidence, fracture because of fatigue through flexure occurs because of metal fatigue, this study aimed to assess the effect of curvature angle and rotational speed on the cyclic fatigue of different type of Endodontic NiTi Rotary Instruments and compare among them. Materials and method: three types of rotary instruments with tip size 0.25: ProTaPer F2 (Densply,Malifier) Revo-S SU ( 0.06 taper, MicroMega) and RaCe system (0.06 taper, FKG,Dentaire), Forty file of each instrument were used within two canals with angle of curvature (40 &60 )at two speed (250&400)RPM, twelve group were formed for all instruments(total number=120),ten file for each group. The testing canals customized within stainless steel block covered with glass face, the time to fracture recorded and the mean of cycles to fracture (MCF) detected for each instrument .Data were analyzed statistically by ANOVA, LSD and Independent T-test at 5% significant level. Result: there was a highly significant difference of curvature angle and significant difference of rotational speed on the fracture resistance of instruments. RaCe revealed the best fracture resistance followed by ProTaper then Revo-s that showed the less resistance. Conclusion: the rotary instruments more prone to fracture when used at more curvature angle and higher rotational speed, as well as the rotary instruments differ from each other according to manufacturing process, taper ,cross section and other factors.
Cyclic fatigue of different nickel-titanium endodontic rotary instruments
Oral Surgery, Oral Medicine, Oral Pathology, Oral Radiology, and Endodontology, 2006
A comparative study of the fatigue resistance of rotary nickel-titanium endodontic instruments was performed with the aim of assessing the influence of both instrument design and surface treatment on flexural fracture. Study design. To evaluate fatigue resistance of different rotary instruments, a total of 120 instruments were tested; these came from different sources: ProFile, RaCe, K3, Hero, and Mtwo. To compare the effect of electro-polishing procedures on fatigue resistance, a group of RaCe instruments (which are normally electro-polished) without surface treatment was used. A scanning electron microscope (SEM) study for each instrument was performed before and after fatigue study to determine the mode of fracture and the aspect of tips and cross-sectional surface areas. Results. ProFile instruments gave the best values for fatigue resistance. It was seen that for RaCe instruments the surface treatment reduces the presence of micro-cracks, surface debris, and machining damage.