Influence of Heat Treatment of Nickel-Titanium Rotary Endodontic Instruments on Apical Preparation: A Micro–Computed Tomographic Study

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.

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Accuracy of third-order bends of nickel-titanium wires and the effect of high and low pressure during memorizing heat treatment

American Journal of Orthodontics and Dentofacial Orthopedics ◽

10.1016/j.ajodo.2003.07.011 ◽

2004 ◽

Vol 126 (4) ◽

pp. 476-484 ◽

Cited By ~ 3

Author(s):

Thomas Stamm ◽

Ariane Hohoff ◽

Dirk Wiechmann ◽

Jan Sütfeld ◽

Dirk Helm

Keyword(s):

Heat Treatment ◽

Low Pressure ◽

Nickel Titanium ◽

Third Order

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Phase Transformations in Sputtered Ni-Ti Film: Effects of Heat Treatment and Precipitates

MRS Proceedings ◽

10.1557/proc-230-91 ◽

1991 ◽

Vol 230 ◽

Cited By ~ 6

Author(s):

J. D. Busch ◽

Mitchell H. Berkson ◽

A. D. Johnson

Keyword(s):

Electron Microscopy ◽

Heat Treatment ◽

Transmission Electron Microscopy ◽

Phase Transformation ◽

Nickel Titanium ◽

Transformation Temperatures ◽

Free Film ◽

Transmission Electron ◽

Sputter Deposited ◽

Isothermal Heat Treatments

AbstractThis research investigated the influence of heat treatment and precipitation on the phase transformation temperatures of sputter-deposited nickel-titanium films. Films 5 to 10 microns thick were subjected to isochronal and isothermal heat treatments in vacuum. Four-point resistance measutements were made and the TP, TR, Ma, and Mc temperatures identified. The correlation between transformation temperatures and the film's microstructure was studied using transmission electron microscopy. Existence of Ti2Ni and Ti11Ni14 precipitates was seen to adversely influence the phase transformation temperatures. It was concluded that precipitate-free film is preferable for mechanical actuator applications.

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The influence of distal-end heat treatment on deflection of nickel-titanium archwire

Dental Press Journal of Orthodontics ◽

10.1590/2177-6709.21.1.083-088.oar ◽

2016 ◽

Vol 21 (1) ◽

pp. 83-88

Author(s):

Marcelo Faria da Silva ◽

Célia Regina Maia Pinzan-Vercelino ◽

Júlio de Araújo Gurgel

Keyword(s):

Heat Treatment ◽

Statistical Significance ◽

Testing Machine ◽

In Vitro Study ◽

Distal Portion ◽

Nickel Titanium ◽

Control Group ◽

Orthodontic Wires ◽

Niti Wires

Objective: The aim of this in vitro study was to evaluate the deflection-force behavior of nickel-titanium (NiTi) orthodontic wires adjacent to the portion submitted to heat treatment. Material and Methods: A total of 106 segments of NiTi wires (0.019 x 0.025-in) and heat-activated NiTi wires (0.016 x 0.022-in) from four commercial brands were tested. The segments were obtained from 80 archwires. For the experimental group, the distal portion of each segmented archwire was subjected to heat treatment (n = 40), while the other distal portion of the same archwire was used as a heating-free control group (n = 40). Deflection tests were performed in a temperature-controlled universal testing machine. Unpaired Student's t-tests were applied to determine if there were differences between the experimental and control groups for each commercial brand and size of wire. Statistical significance was set at p < 0.05. Results: There were no statistically significant differences between the tested groups with the same size and brand of wire. Conclusions: Heat treatment applied to the distal ends of rectangular NiTi archwires does not permanently change the elastic properties of the adjacent portions.

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