scholarly journals Microscopic Features of Fractured Fragment of Nickel-Titanium Endodontic Instruments by Two Different Modes of Torsional Loading

Scanning ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-5 ◽  
Author(s):  
Ibrahim H. Abu-Tahun ◽  
Sang Won Kwak ◽  
Jung-Hong Ha ◽  
Hyeon-Cheol Kim
Keyword(s):  
Cross Sections ◽  
Nickel Titanium ◽  
Original Position ◽  
Torsional Loading ◽  
Fracture Feature ◽  
Topographic Features ◽  
Rotary Instruments ◽  
Microscopic Features ◽  
Loading Methods ◽  
Niti Rotary Instruments

This study compared the microscopic features of the fractured endodontic nickel-titanium (NiTi) rotary instruments by two different torsional loadings: repetitive torsional loading (RTL) and single torsional loading (STL) based on the International Organization for Standardization (ISO). ProTaper Next, HyFlex EDM, and V-Taper 2 were compared in this study. In the STL method, the torsional load was applied after fixing the 3 mm tip of the file, by continuous clockwise rotation (2 rpm) until fracture. In the RTL method, a preset rotational loading (0.5 N·cm) was applied and the clockwise loading to the preset torque and counterclockwise unloading to original position were repeated at 50 rpm until the file fractured. Fractured fragments by two methods were compared under a scanning electron microscope (SEM) to examine the topographic features of the fractured surfaces and longitudinal aspects. SEM examinations showed significantly different features according to the loading methods. Specimens from the RTL method showed ruptured aspects on cross sections, with multiple areas of initiated cracks while the STL method showed the typical features of torsional failure, such as circular abrasion marks and fatigue dimples. This study suggested a new repetitive torsional loading method which is much more clinically relevant and may result in a different fracture feature from STL method.

scholarly journals Comparison of Air-driven vs Electric Torque Control Motors on Canal Centering Ability by ProTaper NiTi Rotary Instruments

2013 ◽  
Vol 14 (1) ◽  
pp. 71-75 ◽  
Author(s):  
Mina Zarei ◽  
Maryam Javidi ◽  
Mahdi Erfanian ◽  
Mahdi Lomee ◽  
Farzaneh Afkhami
Keyword(s):  
Cross Sections ◽  
Root Canal ◽  
Ex Vivo ◽  
Controlled Trial ◽  
Acrylic Resin ◽  
Torque Control ◽  
Rotary Instruments ◽  
Canal Transportation ◽  
Group 2 ◽  
Niti Rotary Instruments

ABSTRACT Aim Cleaning and shaping is one of the most important phases in root canal therapy. Various rotary NiTi systems minimize accidents and facilitate the shaping process. Todays NiTi files are used with air-driven and electric handpieces. This study compared the canal centering after instrumentation using the ProTaper system using Endo IT, electric torque-control motor, and NSK air-driven handpiece. Materials and methods This ex vivo randomized controlled trial study involved 26 mesial mandibular root canals with 10 to 35° curvature. The roots were randomly divided into 2 groups of 13 canals each. The roots were mounted in an endodontic cube with acrylic resin, sectioned horizontally at 2, 6 and 10 mm from the apex and then reassembled. The canals were instrumented according to the manufacturer's instructions using ProTaper rotary files and electric torque-control motors (group 1) or air-driven handpieces (group 2). Photographs of the cross-sections included shots before and after instrumentation, and image analysis was performed using Photoshop software. The centering ability and canal transportation was also evaluated. Repeated measurement and independent t-test provided statistical analysis of canal transportation. Results The comparison of the rate of transportation toward internal or external walls between the two groups was not statistically significant (p = 0.62). Comparison of the rate of transportation of sections within one group was not significant (p = 0.28). Conclusion Use of rotary NiTi file with either electric torquecontrol motor or air-driven handpiece had no effect on canal centering. Clinical significance NiTi rotary instruments can be used with air-driven motors without any considerable changes in root canal anatomy, however it needs the clinician to be expert. How to cite this article Zarei M, Javidi M, Erfanian M, Lomee M, Afkhami F. Comparison of Air-driven vs Electric Torque Control Motors on Canal Centering Ability by ProTaper NiTi Rotary Instruments. J Contemp Dent Pract 2013;14(1):71-75.

scholarly journals Torsional Resistance of Heat-Treated Nickel-Titanium Instruments under Different Temperature Conditions

Materials ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5295
Author(s):  
Hyo Jin Jo ◽  
Sang Won Kwak ◽  
Hyeon-Cheol Kim ◽  
Sung Kyo Kim ◽  
Jung-Hong Ha
Keyword(s):  
Nickel Titanium ◽  
Phase Transformation Temperature ◽  
Scanning Calorimetry ◽  
Temperature Conditions ◽  
Torsional Resistance ◽  
Heat Treated ◽  
Rotary Instruments ◽  
Single Use ◽  
Niti Instruments ◽  
Niti Rotary Instruments

This study compared the torsional resistance of heat-treated nickel-titanium (NiTi) instruments under different temperature conditions. Four thermomechanically treated single-use NiTi rotary instruments were selected for this study: OneShape (OS), OneCurve (OC), WaveOne Gold (WOG) and HyFlex EDM (HFE). Each instrument was further subdivided by temperature into 2 subgroups. Maximum torque and the distortion angle until fracture occurred were evaluated. Differential scanning calorimetry analysis was performed to measure the phase transformation temperature. Statistical analysis was performed using a two-way ANOVA and t-test (p < 0.05). Fractured fragments were observed using scanning electron microscopy (SEM). The two-way ANOVA showed no significant differences for different temperature conditions. At both room (RT) and body temperature (BT), OS was predominantly austenite while HFE was martensite. OC and WOG were predominantly martensite at RT and mixed phase at BT. At BT, more than half of WOG was martensite, while half of OC was austenite. SEM examination showed no topographical differences between instruments in different temperature groups. In relation to a limitation of this study, there was no difference in torsional resistance of NiTi rotary instruments between the BT and RT conditions. This implies that clinicians do not need to consider a decrease of torsional resistance of heat-treated NiTi instruments at BT.

scholarly journals Geometric Analysis of Maxillary First Premolar Prepared by Two Nickel-Titanium Rotary Instruments

2014 ◽  
Vol 15 (2) ◽  
pp. 174-180 ◽  
Author(s):  
Dina Al-Sudani ◽  
Majed Almalki ◽  
Saad Al-Shahrani ◽  
Michael Ahlquist
Keyword(s):  
Cross Sections ◽  
Root Canal ◽  
Geometric Analysis ◽  
Microcomputed Tomography ◽  
Nickel Titanium ◽  
Rotary Instruments ◽  
Significant Difference ◽  
Before And After ◽  
Canal Transportation ◽  
Shaping Ability

ABSTRACT Aim The present study was conducted with the aim of evaluating and comparing the shaping ability of two Nickel-titanium rotary instruments, with two disparate design features, on root canal geometry of extracted human maxillary first premolars using microcomputed tomography. Study design Twenty four bifurcated maxillary first premolars were divided into two groups and embedded in a rubber-based impression material. Both groups were submitted to microcomputed tomography before and after canal preparation (buccal and palatal) with either ProFile Vortex or Revo-S rotary instruments. Images were reconstructed and cross-sections corresponding to a distance 1, 2, 3, 4, 5, 6, and 7 mm from the anatomical apex were selected for canal transportation analysis. Volume changes were also measured. Results The degree and direction of canal transportation were non-significant for both instruments. Statistically significant differences were observed only between levels in the buccal canal in both groups. There was no significant difference between the two rotary systems in regards to the volume of dentin removed. Conclusion Our findings showed that ProFile Vortex and Revo-S instruments respected the original root canal anatomy and behaved similarly. ProFile Vortex rotary systems produced with innovative process were concluded to shape the upper maxillary premolar by leading minimal canal transportation, similar to Revo-S, rotary systems produced from traditional process. How to cite this article Al-Sudani D, Almalki M, Al-Shahrani S, Ahlquist M. Geometric Analysis of Maxillary First Premolar Prepared by Two Nickel-Titanium Rotary Instruments. J Contemp Dent Pract 2014;15(2):174-180.

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.

scholarly journals Evaluation of Flexibility, Microstructure and Elemental Analysis of Some Contemporary Nickel-Titanium Rotary Instruments

2019 ◽  
Vol 7 (21) ◽  
pp. 3647-3654 ◽  
Author(s):  
Tamer M. Hamdy ◽  
Manar Galal ◽  
Amira Galal Ismail ◽  
Rasha M. Abdelraouf
Keyword(s):  
Elemental Analysis ◽  
Great Influence ◽  
Nickel Titanium ◽  
Bending Test ◽  
Uniform Structure ◽  
Rotary Instruments ◽  
Significant Difference ◽  
Cantilever Bending ◽  
Niti Rotary Instruments ◽  
Rotary Instrument

BACKGROUND: Contemporary nickel-titanium (NiTi) rotary endodontic instruments had a revolutionary impact on the success of root canal treatment. AIM: To evaluate the flexibility, microstructure and elemental analysis of four different recent NiTi rotary instruments, namely; Wave One Gold, TF adaptive, HyFlex EDM and Gr_Reciproc Blue compared to conventional Protaper Universal (F2). MATERIAL AND METHODS: The NiTi rotary files were subjected to cantilever bending test to evaluate their flexibility. The microstructural characteristics and elemental analysis were examined via scanning electron microscopy (SEM) and energy dispersive X-ray spectrometer (EDX). RESULTS: The TF adaptive, HyFlex EDM and Wave One Gold endodontic files showed significantly lower cantilever bending values (i.e., higher flexibility) than Protaper F2 and Gr_Reciproc Blue (p < 0.05). The SEM micrographs showed that the bulk of all examined files showed multiple striations due to the cutting process, on the other hand, their external surfaces were different: The Protaper Universal F2 showed multiple voids, while the TF Adaptive surface exhibited more uniform structure. The Hyflex EDM had a crater-like surface, whereas Wave one Gold showed machining grooves with minimum defects, while Reciproc Blue displayed machining grooves with random scratch lines. There was a significant difference in bulk and surface elemental analysis of the various examined files, yet composed mainly of the same elements. CONCLUSION: Chemical composition, heat treatment, manufacturing process and geometrical design of the NiTi rotary instrument have a great influence on their flexibility and microstructure.

scholarly journals Information regarding use of rotary nickel -titanium endodontic instruments among general dental practitioners: a questionnaire survey

2016 ◽  
Vol 4 (1) ◽  
pp. 4
Author(s):  
Ritu Meel ◽  
Deepak Raisingani ◽  
Ashwini Prasad ◽  
Rachit Mathur ◽  
Nidha Madan ◽  
...  
Keyword(s):  
Questionnaire Survey ◽  
Nickel Titanium ◽  
Cross Sectional ◽  
Rotary Instruments ◽  
Dental Practitioners ◽  
Instruments And Techniques ◽  
Niti Instruments ◽  
General Dentists ◽  
Niti Rotary Instruments

Aim: A cross-sectional questionnaire survey was conducted to obtain information on the use of rotary nickel –titanium endodontic instruments was conducted among General Dental Practioner A two sectioned questionnaire was mailed to 200 randomly general practioners to obtain information on usage of Nickel –Titanium endodontic instrument and data was collected.Results: Forty-six percent of the general practioners had used rotary NiTi instruments. 76% dentists use NiTi files for five or more times a week. Most of the dentist used NiTi file coronally &apically. General dentists experienced more file fracture at size 20 and 25 with 0.02 and 0.04 taper.Conclusions: Dentists are familiar with limitations of NiTi instruments and techniques. Current study showed the awareness of dentists about benefits of NiTi rotary instruments application comparing to traditional techniques and also the high percent usage of these instruments among general dentists.

scholarly journals The efficacy of XP-endo SHAPER (XPS) in cleaning the apical third of the root canal

2017 ◽  
Vol 64 (4) ◽  
pp. 171-178
Author(s):  
Slavoljub Živković ◽  
Jelena Nešković ◽  
Milica Jovanović-Medojević ◽  
Marijana Popović-Bajić ◽  
Marija Živković-Sandić
Keyword(s):  
Cross Sections ◽  
Root Canal ◽  
Sem Analysis ◽  
Smear Layer ◽  
Rotary Instruments ◽  
New Instrument ◽  
Niti Instruments ◽  
Niti Rotary Instruments ◽  
Apical Area

Abstract Introduction The aim of this study was to evaluate the efficacy of new rotary NiTi instrument XP endo SHAPER (XPS) used with conventional irrigation protocol on the root canal cleaning in the apical area. Material and methods The research was conducted in vitro on 40 extracted single-rooted teeth divided into the four groups. Instrumentation in the first group was performed using iRa Ce NiTi rotary instruments, in the second group the same instruments were used plus XP endo FINISHER (XPF) for smear layer removal. In the third group, canal instrumentation was done using new instrument XPS, and in the fourth XPS instruments plus XPF was used. During the instrumentation 2% NaOCl solution was used for rinsing canals. The SEM analysis of the cleaning quality in the apical third of the canal was performed on longitudinal root cross-sections and standardized microphotography with a 2000x magnification. Results The thickest smear layer in the apical third was recorded in the first group (iRa Ce) NiTi instruments (2.12), and somewhat less in the group with the new XPS instrument (1.95). An identical and somewhat smaller amount of smear layer was registered in the second and fourth groups where XPF was used with the final irrigant (1.64) (p<0.001). Conclusion The application of only one instrument (XPS) in the canal enabled efficient cleaning of a very complex apical third. Cleaning was more efficient when XPF was used with final irrigant after the canal instrumentation.

scholarly journals Deformation of Nickel-Titanium (NiTi) rotary instruments in cyclic loading – in vitro study

2018 ◽  
Vol 65 (2) ◽  
pp. 61-70
Author(s):  
Isidora Nešković ◽  
Igor Stojanac ◽  
Sanja Vujkov ◽  
Jovan Laban Terzija ◽  
Aleksandra Maletin
Keyword(s):  
Root Canal ◽  
Statistical Significance ◽  
Nickel Titanium ◽  
Torque Control ◽  
Matched Pair ◽  
Human Teeth ◽  
Rotary Instruments ◽  
Significant Difference ◽  
Niti Rotary Instruments

Summary Introduction Separation of instruments in the root canal is one of the challenges in endodontic treatment. More specifically, nickel-titanium (NiTi) rotary instruments usually separate without previous deformation. The aim of this pilot study was to assess the effect of torsional stress on endodontic NiTi rotary instruments separation in simulated clinical conditions. Materials and methods Research was conducted on a sample of 20 human teeth in laboratory conditions. Experimental procedure consisted of determining canal curvatures for each root on digital radiographs and root canal treatment using endodontic NiTi rotary instruments. Out of 20 teeth (60 canals), two groups were formed with similar root canal curvatures (10 pairs of teeth) and instrumented using NiTi rotary instrument with or without torque control. Results Wilcoxon matched pair test showed no statistically significant difference in average number of instruments use with or without torque control (p>0.05). Conclusion Even though there is no statistical significance in instrument separation when instruments were used with or without torque, there is tendency to experience sudden fracture of instruments after work without torsional control even after only few uses in clinical work.

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 Mechanical and Metallurgical Properties of Various Nickel-Titanium Rotary Instruments

2017 ◽  
Vol 2017 ◽  
pp. 1-13 ◽  
Author(s):  
Kyu-Sang Shim ◽  
Soram Oh ◽  
KeeYeon Kum ◽  
Yu-Chan Kim ◽  
Kwang-Koo Jee ◽  
...  
Keyword(s):  
Angular Displacement ◽  
Cyclic Fatigue ◽  
Nickel Titanium ◽  
Scanning Calorimetry ◽  
Metallurgical Properties ◽  
Rotary Instruments ◽  
Conventional Instrument ◽  
Conventional Alloy ◽  
Niti Instruments ◽  
Niti Rotary Instruments

The aim of this study was to investigate the effect of thermomechanical treatment on mechanical and metallurgical properties of nickel-titanium (NiTi) rotary instruments. Eight kinds of NiTi rotary instruments with sizes of ISO #25 were selected: ProFile, K3, and One Shape for the conventional alloy; ProTaper NEXT, Reciproc, and WaveOne for the M-wire alloy; HyFlex CM for the controlled memory- (CM-) wire; and TF for the R-phase alloy. Torsional fracture and cyclic fatigue fracture tests were performed. Products underwent a differential scanning calorimetry (DSC) analysis. The CM-wire and R-phase groups had the lowest elastic modulus, followed by the M-wire group. The maximum torque of the M-wire instrument was comparable to that of a conventional instrument, while those of the CM-wire and R-phase instruments were lower. The angular displacement at failure (ADF) for the CM-wire and R-phase instruments was higher than that of conventional instruments, and ADF of the M-wire instruments was lower. The cyclic fatigue resistance of the thermomechanically treated NiTi instruments was higher. DSC plots revealed that NiTi instruments made with the conventional alloy were primarily composed of austenite at room temperature; stable martensite and R-phase were found in thermomechanically treated instruments.

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