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 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 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.

scholarly journals Nickel–Titanium Rotary Instruments: An In Vitro Comparison (Torsional Resistance of Two Heat-treated Reciprocating Files)

2021 ◽  
Vol 22 (4) ◽  
pp. 361-364
Author(s):  
Shilpa Bhandi ◽  
Gianluca Gambarini ◽  
Marco Seracchiani ◽  
Luca Testarelli ◽  
Alessandro Mazzoni ◽  
...  
Keyword(s):  
Nickel Titanium ◽  
Torsional Resistance ◽  
Heat Treated ◽  
Rotary Instruments ◽  
In Vitro Comparison

scholarly journals Torsional Resistance of Two New Heat Treated Nickel Titanium Rotary Instruments: An in Vitro Evaluation

2020 ◽  
Vol 20 ◽  
Author(s):  
Gianluca Gambarini ◽  
Gabriele Miccoli ◽  
Dario Di Nardo ◽  
Andrea Del Giudice ◽  
Alessandro Mazzoni ◽  
...  
Keyword(s):  
Nickel Titanium ◽  
In Vitro Evaluation ◽  
Torsional Resistance ◽  
Heat Treated ◽  
Rotary Instruments

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 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 Role of the Crystallographic Phase of NiTi Rotary Instruments in Determining Their Torsional Resistance during Different Bending Conditions

Materials ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 6324
Author(s):  
Alessio Zanza ◽  
Marco Seracchiani ◽  
Rodolfo Reda ◽  
Dario Di Nardo ◽  
Gianluca Gambarini ◽  
...  
Keyword(s):  
Nickel Titanium ◽  
Radius Of Curvature ◽  
Maximum Torque ◽  
Torsional Resistance ◽  
Rotary Instruments ◽  
Significant Difference ◽  
Torsional Test ◽  
Torque Values ◽  
Niti Rotary Instruments

The aim of this study was to assess the role of the crystallographic phase of Nickel-titanium (NiTi) rotary instruments in determining their torsional resistance during different bending conditions, such as different degrees and angles of curvature. 200 F-One 20.04 instruments (Fanta Dental, Shanghai, China) were used, 100 austenitic instruments and 100 martensitic instruments. Each group was divided in 5 subgroups according to the different bending conditions (straight canal, 90° or 60° of curvature degrees and 3 mm or 5 mm of radius of curvature). The static torsional test was performed by using a device composed of an electric motor capable of recording torque values (N·cm); a vice used to secure the instruments at 3 mm from the tip; and artificial canals, which allow instruments to remain flexed during test. Each instrument was rotated at 500 rpm with a torque limit set to 5.5 Ncm until its fracture. Torque at Fracture (TtF) was registered. A scanning electron microscopy (SEM) observation was conducted. The collected data confirm that an increase in the angle of curvature and a decrease in the radius of curvature of the artificial canals lead to an increase of TtF values with a statistically significant difference (p < 0.05), both in the austenitic and martensitic groups. Regarding the comparison between austenitic and martensitic groups in the same bending condition, a statistically significant difference was found only when the torsional test was performed in the canals with the degrees of curvature of 90° and the radius of curvature of 3 mm and 5 mm, with the austenitic instruments showing a higher TtF than the martensitic ones. In conclusion, it can be stated that the crystallographic phase influences the maximum torque at fracture when the instruments are subjected to severe bending and that the radius of curvature significantly influences their torsional resistance.

scholarly journals Influence of Different Heat Treatments on Torsional and Cyclic Fatigue Resistance of Nickel–Titanium Rotary Files: A Comparative Study

2020 ◽  
Vol 10 (16) ◽  
pp. 5604 ◽  
Author(s):  
Gianluca Gambarini ◽  
Andrea Cicconetti ◽  
Dario Di Nardo ◽  
Gabriele Miccoli ◽  
Alessio Zanza ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Fatigue Resistance ◽  
Cyclic Fatigue ◽  
Sem Analysis ◽  
Nickel Titanium ◽  
Torsional Resistance ◽  
Heat Treated ◽  
Torsional Test ◽  
Time To Fracture ◽  
Flexural Resistance

Protaper Universal (PTU), Protaper Gold (PTG) (Maillefer, Ballaigues, CH), EdgeTaper (ET), and EdgeTaper Platinum (ETP) (Albuquerque, NM, USA) were tested for both torsional and flexural resistance. The aim of the present study was to evaluate the influence of proprietary heat treatment on the metallurgical properties of the aforementioned instruments. Four groups of 30 different instruments (size 20.07) were tested, then divided into two subgroups of 15 instruments—one for the cyclic fatigue test in a curved canal (90°—2 mm radius) at 300 rpm and 2.5 Ncm. The time to fracture (TtF) and fragment length (FL) were recorded. The other subgroup was subjected to the torsional test (300 rpm, 5.5 Ncm). The torque to fracture and TtF were recorded. All the instruments underwent a SEM analysis. The heat-treated instruments showed a significantly higher fatigue resistance than the non-heat-treated instruments (p < 0.05). No significant differences were found in the torsional resistance between the ET and PTU, and the ETP and PTG. However, when comparing all the groups, the heat-treated instruments showed less torsional resistance. The improvement from heat treatment was mainly found in the cyclic fatigue resistance.

Comparison of the flexibility and torsional resistance of nickel-titanium rotary instruments

2013 ◽  
pp. 16-22
Author(s):  
Weber Schmidt Pereira Lopes ◽  
Hélio Pereira Lopes ◽  
Carlos Nelson Elias ◽  
Marcelo Mangelli ◽  
Márcia Valéria Boussada Vieira
Keyword(s):  
Nickel Titanium ◽  
Torsional Resistance ◽  
Rotary Instruments

Comparison of the Effects of Three Different Nickel–titanium Rotary Instruments on the Fracture Resistance of Obturated Roots: An in vitro Study

2017 ◽  
Vol 7 (2) ◽  
pp. 86-90
Author(s):  
Vanitha U Shenoy ◽  
Ritesh B Pawar ◽  
Sumanthini MV ◽  
Saimanaaz AH Shaikh
Keyword(s):  
Fracture Resistance ◽  
Testing Machine ◽  
In Vitro Study ◽  
Nickel Titanium ◽  
Endodontically Treated Teeth ◽  
Term Survival ◽  
Group I ◽  
Rotary Instruments ◽  
Niti Instruments

ABSTRACT Aim The aim of the article is to compare the effects of three different nickel–titanium (NiTi) rotary instruments on the fracture resistance of obturated roots. Materials and methods A total of 100 permanent mandibular premolars were randomly divided into four groups of 25 teeth each and biomechanical preparation was done: group I: stainless steel K-hand files (HFs), group II: ProTaper NiTi instruments (PT), group III: HyFlex CM NiTi instruments (HCM), and group IV: K3XF NiTi instruments. Following root canal preparation, the canals were obturated using lateral condensation. A light body silicone impression material was used to simulate the periodontal ligament (PDL). Fracture resistance was tested in an Instron testing machine. Statistical analysis Data were analyzed with Kruskal–Wallis test. Results There was no difference in significance (p < 0.05) among the different groups tested with respect to their fracture resistances. Conclusion The present study concluded that rotary instrumentation could result in an increased chance for dentinal defects as compared with hand instrumentation. Greater taper rotary NiTi instruments do not increase the fracture susceptibility of roots, which in turn depends on various factors other than instrumentation alone. Clinical significance Greater taper achieved by rotary NiTi files during canal preparation facilitates efficient irrigation and complete debridement. Root fracture might occur as a result of microcracks or craze lines that propagate with repeated stress application by occlusal forces and also during canal preparation. Based on the results obtained, it can be decided whether the use of the newer rotary NiTi system contributes to endodontic success and long-term survival of endodontically treated teeth. How to cite this article Shaikh SAH, Shenoy VU, Sumanthini MV, Pawar RB. Comparison of the Effects of Three Different Nickel–titanium Rotary Instruments on the Fracture Resistance of Obturated Roots: An in vitro Study. J Contemp Dent 2017;7(2):86-90.

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