scholarly journals Load-Deflection Characteristics of Superelastic Nickel-Titanium Wires

2007 ◽  
Vol 77 (6) ◽  
pp. 991-998 ◽  
Author(s):  
Theodosia N. Bartzela ◽  
Christiane Senn ◽  
Andrea Wichelhaus
Keyword(s):  
Niti Alloy ◽  
Permanent Deformation ◽  
Nickel Titanium ◽  
Bending Test ◽  
Qualitative Behavior ◽  
Treatment Needs ◽  
Orthodontic Wires ◽  
Three Point Bending ◽  
Niti Wires ◽  
The Given

Abstract Objective: To determine the mechanical properties of commercially available thermodynamic wires and to classify these wires mathematically into different groups. Materials and Methods: The samples examined were 48 nickel-titanium (NiTi) alloy orthodontic wires commercially available from five manufacturers. These samples included 0.016-inch, 0.016- × 0.022-inch, 0.017- × 0.025-inch, and 0.018- × 0.025-inch wires. The superelastic properties of the NiTi wires were evaluated by conducting the three-point bending test under uniform testing conditions. The group classification was made under mathematically restricted parameters, and the final classification was according to their clinical plateau length. Results: The orthodontic wires tested are classified as follows: (1) true superelastic wires, which presented a clinical plateau length of ≥0.5 mm; (2) borderline superelastic with a clinical plateau length of <0.5 mm and >0.05 mm; and (3) nonsuperelastic, with a clinical plateau length of ≤0.05 mm. The results showed that the range of products displays big variations in quantitative and qualitative behavior. A fraction of the tested wires showed weak superelasticity, and others showed no superelasticity. Some of the products showed permanent deformation after the three-point bending test. Conclusion: A significant fraction of the tested wires showed no or only weak superelasticity. The practitioner should be informed for the load-deflection characteristics of the NiTi orthodontic wires to choose the proper products for the given treatment needs.

Comparison of Mechanical Properties of Plain and Reversed Curve Nickel-Titanium Archwires

2019 ◽  
Vol 814 ◽  
pp. 372-377
Author(s):  
Kanuengnit Pongpat ◽  
Niwat Anuwongnukroh ◽  
Surachai Dechkunakorn ◽  
Wassana Wichai ◽  
Peerapong Tua-Ngam
Keyword(s):  
Mechanical Properties ◽  
Surface Hardness ◽  
Nickel Titanium ◽  
Bending Test ◽  
Vertical Force ◽  
Three Point Bending ◽  
Hardness Tester ◽  
Curve Of Spee ◽  
Group 2 ◽  
Niti Wires

In orthodontics, nickel-titanium wires are used for teeth alignment and leveling. For leveling the curve of Spee, reversed curve archwires are often used to increase the vertical force needed to correct a deep bite.Objectives: The aims of this study were to investigate and compare the mechanical properties (unloading force, stiffness, springback, and surface hardness) of the pre-formed plain and reversed curved NiTi archwires.Materials and Methods: NiTi wires of dimensions 0.016x0.022 inch were divided into two groups, Group 1 - plain and Group 2- reversed curve NiTi archwires. For each type of the archwire, load-deflection curve obtained from a three-point bending test, performed by a Texture Analyser (TA.XT.plus, Stable Micro System, United Kingdom) with 5 kg load cell at room temperature, was used to analyze unloading force, springback, and stiffness. Surface hardness was measured by Vickers micro-hardness tester. Kruskal-Wallis test was used to analyze the variables of this study.Results: The results showed that the unloading force of each deflection point of the reversed curve NiTi archwire was more than the plain archwire. The means of unloading force, stiffness, and springback were 2.42 N, 2.76 N; 0.28 N/mm, 0.49 N/mm; and 2.94 mm, 2.98 mm for the plain archwire and reversed curve NiTi archwire, respectively. The properties of reversed curve NiTi archwire were significantly higher (p<0.05) than the plain NiTi archwire, except the springback. The surface hardness of the plain archwire was significantly higher (p<0.05) than reversed curve NiTi archwire in each segment.Conclusion: The reversed curve NiTi archwire had more unloading force and stiffness than plain NiTi archwire. For the correction of deep curve of Spee in orthodontic treatment, clinicians must be aware of the vertical force needed during intrusion of lower incisors or the wires should be used in the later leveling and aligning stage.

Mechanical Properties of Several NiTi Alloy Wires in Three-Point Bending Tests

2011 ◽  
Vol 87 ◽  
pp. 14-19 ◽  
Author(s):  
Surachai Dechkunakorn ◽  
Rutchadakorn Isarapatanapong ◽  
Niwat Anuwongnukroh ◽  
Nattiree Chiranavanit ◽  
Julathep Kajorchaiyakul ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Niti Alloy ◽  
Bending Test ◽  
Dental Arch ◽  
Orthodontic Wires ◽  
Niti Wire ◽  
Bending Tests ◽  
Three Point Bending ◽  
Loading And Unloading ◽  
Deflection Rate

Objective: To clarify mechanical properties of 14 superelastic NiTi orthodontic wires by three-point bending tests. Materials and Methods: The three-point bending test was conducted with a midspan deflection rate of 5 mm/min under constant temperature range 36±1°C. Wires were deflected to 3.1 mm. All data were recorded during the unloading process at deflections 3, 2, 1 and 0.5 mm. to simulate the force a wire exerts as a tooth is moved into the dental arch from a position of malocclusion. Results: The delivered forces changed slightly when the deflection varied during loading and unloading. Sentalloy wire applied the lowest continuous force. Conclusions: Commercial wires may not behave similarly due to minor differences in the production process, and force varies greatly from brand to brand. NiTi wire brands must be selected carefully considering the severity of malocclusion and stage of orthodontic treatment.

scholarly journals Influence of aesthetic coating on the load-deflection ratio of nickel–titanium archwires

2017 ◽  
Vol 15 (4) ◽  
pp. 293
Author(s):  
Marcus Vinicius Neiva Nunes do Rego ◽  
Gislayne Maria Mesquita de Araújo ◽  
Elizabeth Ferreira Martinez ◽  
Kássio Rafael de Sousa Lima ◽  
Pio Thiago Feitosa Fortes ◽  
...  
Keyword(s):  
Testing Machine ◽  
Nickel Titanium ◽  
Bending Test ◽  
Orthodontic Wires ◽  
Group 4 ◽  
San Marcos ◽  
Group 5 ◽  
Coated Wires ◽  
Group 2 ◽  
Niti Wires

Aim: To assess the influence of aesthetic surface coating on load-deflection ratios in nickel-titanium (NiTi) orthodontic wires compared with uncoated wires. Methods: NiTi wires (0.016") from four different manufacturers (Morelli, Sorocaba, SP, Brazil; TP, La Porte, IN, USA; Eurodonto, Curitiba, PR, Brazil; Ortho Organizers, San Marcos, CA, USA) were divided into eight groups, according to presence or absence of coating: group 1, Morelli coated wire; group 2, Morelli uncoated; group 3, TP coated; group 4, TP uncoated; group 5, Eurodonto coated; group 6, Eurodonto uncoated; group 7, Ortho Organizers coated; group 8, Ortho Organizers uncoated. To determine the load-deflection ratio, a three-point bending test was performed in a AGS-X 250 KN (Shimadzu) universal testing machine. Results: The results showed that aesthetic coatings did not influence load-deflection ratio in NiTi orthodontic wires at 1-mm and 2-mm activation. However, comparison across the four tested brands revealed that Eurodonto coated wires exhibited the greatest force levels at 1-mm, 2-mm, and 3-mm deflection. At 3-mm deflection, Ortho Organizers coated wires exhibited lower force levels than all other tested brands, except for TP wires. Conclusions: We conclude that the load-deflection ratio of NiTi wires was not influenced significantly by aesthetic coatings, especially at lower activations.

scholarly journals DSC analysis and evaluation of forces released on deactivation of 0.40-mm (0.016") orthodontic thermo-activated NiTi wires: An in vitro study

2020 ◽  
Vol 14 (1) ◽  
pp. 12-18
Author(s):  
Vítor Marques Sapata ◽  
Diogo Marques Sapata ◽  
Julio Araújo Gurgel ◽  
Antônio Medina Neto ◽  
Adilson Luiz Ramos
Keyword(s):  
Structural Phase ◽  
In Vitro Study ◽  
Bending Test ◽  
Dsc Analysis ◽  
Scanning Calorimetry ◽  
Orthodontic Wires ◽  
Three Point Bending ◽  
Niti Alloys ◽  
Niti Wires

Background . This study evaluated the phase transformation of NiTi orthodontic wires and forces they release on deactivation. Methods. The structural phase transformations of the following five thermo-activated nickel-titanium (NiTi) wires were evaluated using differential scanning calorimetry (DSC): Flexy Thermal Sentalloy® (GAC International), NiTi (35ºC) (Eurodonto), Thermo-Plus® (Morelli), FlexyNiTi® Flexy Thermal (35ºC) (Orthometric) and Damon® CuNiTi (35ºC) (ORMCO Corp.). The wires had a cross-section of 0.40 mm (0.016"). In addition, the forces they released were investigated using the three-point bending test. Five arches of each wire were tested using DSC (-20/80ºC at 10ºC/min), and six arches from each wire were sectioned for bending tests. The data were analyzed with ANOVA and post hoc Tukey tests. Pearson’s correlation test was performed between the results yielded by the DSC tests and those by three-point analyses (P=0.05). Results. The DSC analysis showed differences between the NiTi alloys from all the manufacturers, with no differences between the lots of the same brand. ORMCO and Orthometric wires exhibited similar TTR values in cooling (P=0.49), and statistically similar TTR values in heating (P=0.056). The three-point bending test showed different patterns in releasing forces. A correlation was found between the DSC analysis and the three-point bending test results. Conclusion. The higher the temperature transformation was, the larger was the variation of force. All the wires presented higher forces at 3-mm deflection from 155 (±12.3) to 168.1 (±8) cN. The DSC analysis and the three-point bending test showed differences between the NiTi alloys from all the manufacturers.

scholarly journals Flexural properties of rectangular nickel-titanium orthodontic wires when used as ribbon archwires

2018 ◽  
Vol 89 (1) ◽  
pp. 54-63
Author(s):  
Li Lin ◽  
G. Fräns Currier ◽  
Onur Kadioglu ◽  
Fernando L. Esteban Florez ◽  
David M Thompson ◽  
...  
Keyword(s):  
Standardized Test ◽  
Nickel Titanium ◽  
Test Method ◽  
Bending Test ◽  
Flexural Properties ◽  
Orthodontic Wires ◽  
Mean Values ◽  
Three Point Bending ◽  
Type Size ◽  
Post Hoc

ABSTRACT Objective: To compare the flexural properties of rectangular nickel-titanium (Ni-Ti) orthodontic wires in occlusoapical and faciolingual orientations using a standardized test method. Materials and Methods: Twenty-two rectangular Ni-Ti wire groups were tested in occlusoapical (ribbon) orientation: eight conventional Ni-Ti products, five superelastic Ni-Ti products, and nine thermal Ni-Ti products (n = 10 per group). Six products of thermal Ni-Ti wire were tested in faciolingual (edgewise) orientation. A three-point bending test was performed to measure deactivation force at 3.0-, 2.0-, 1.0-, and 0.5-mm deflections of each rectangular wire at 37.0 ± 0.5°C. Analysis of variance and post hoc Student-Newman-Keuls tests were used to compare the mean values of the different groups (α = .05). Results: The ranges of deactivation forces varied greatly with different kinds, sizes, products, and deflections of Ni-Ti wires. One product of conventional and superelastic Ni-Ti wires had steeper force-deflection curves. Four products had similarly shaped flat force-deflection curves, whereas the sixth product had a moderately steep force-deflection curve. Thermal Ni-Ti wires had smaller deactivation forces ranging from 0.773 N (78.8 g) to 2.475 N (252.4 g) between deflections of 1.0 and 0.5 mm, whereas wider ranges of force from 3.371 N (343.7 g) to 9.343 N (952.7 g) were predominantly found among conventional Ni-Ti wires between deflections of 3.0 and 2.0 mm. Conclusions: Clinicians should critically select archwires for use in the occlusoapical orientation not only based on Ni-Ti wire type, size (0.022 × 0.016-in or 0.025 × 0.017-in), and product but also with deactivation deflections from 0.5 and 1.0 mm to obtain light forces in the occlusoapical orientation.

scholarly journals Mechanical properties of orthodontic wires on ceramic brackets associated with low friction ligatures

2017 ◽  
Vol 46 (3) ◽  
pp. 125-130
Author(s):  
Fernando KOIKE ◽  
Hiroshi MARUO ◽  
Rogério LACERDA-SANTOS ◽  
Matheus Melo PITHON ◽  
Orlando Motohiro TANAKA
Keyword(s):  
Mechanical Properties ◽  
Stainless Steel ◽  
Mechanical Test ◽  
Steel Wire ◽  
Nickel Titanium ◽  
Bending Test ◽  
Test Machine ◽  
Orthodontic Wires ◽  
Niti Wire ◽  
Ceramic Brackets

Abstract Introduction Few studies investigated the mechanical properties of orthodontic wires on ceramic brackets associated the ligatures. Objective This study aimed to compare the load-deflection of orthodontic wires with round section of 0.016” made of stainless steel (SS), nickel-titanium (NiTi) and glass fiber-reinforced polymer composite (GFRPC). Material and method Sixty specimens obtained from 10 sectioned pre-contoured arches (TP Orthodontics), were divided into 3 groups of 20 according to each type of material (1 esthetic-type wire and 2 not esthetic) and length of 50 mm. The methodology consisted of a 3-point bending test using esthetic ceramic brackets (INVU, TP Orthodontics, Edgewise, 0.022”x 0.025”) as points of support. The tensile tests were performed on a mechanical test machine, at a speed of 10 mm/min, deflection of 1 mm, 2 mm and 3 mm. Friedman’s Non Parametric Multiple comparisons test was used (P<0.05). Result The nickel-titanium wire presented smaller load/ deflection compared with stainless steel. GFRPC wires had lower strength values among all groups evaluated (P<.05). The steel wire showed permanent deformation after 3 mm deflection, NiTi wire demonstrated memory effect and the esthetic type had fractures with loss of strength. Conclusion It can be concluded that steel wires have high strength values, requiring the incorporation of loops and folds to reduce the load / deflection. NiTi and GFRPC wires produced low levels of force, however the esthetic wire was shown to fracture and break.

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

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.

scholarly journals Understanding the Shape-Memory Alloys Used in Orthodontics

2011 ◽  
Vol 2011 ◽  
pp. 1-6 ◽  
Author(s):  
Daniel J. Fernandes ◽  
Rafael V. Peres ◽  
Alvaro M. Mendes ◽  
Carlos N. Elias
Keyword(s):  
Shape Memory Alloys ◽  
Shape Memory ◽  
Nickel Titanium ◽  
Orthodontic Wires ◽  
Steel Alloys ◽  
Thermomechanical Characteristics ◽  
Shape Memory Properties ◽  
Niti Wires ◽  
Niti Shape Memory Alloys ◽  
Pseudoelastic Behavior

Nickel-titanium (NiTi) shape-memory alloys (SMAs) have been used in the manufacture of orthodontic wires due to their shape memory properties, super-elasticity, high ductility, and resistance to corrosion. SMAs have greater strength and lower modulus of elasticity when compared with stainless steel alloys. The pseudoelastic behavior of NiTi wires means that on unloading they return to their original shape by delivering light continuous forces over a wider range of deformation which is claimed to allow dental displacements. The aim of this paper is to discuss the physical, metallurgical, and mechanical properties of NiTi used in Orthodontics in order to analyze the shape memory properties, super-elasticity, and thermomechanical characteristics of SMA.

scholarly journals Evaluation of the Loading, Unloading, and Permanent Deformation of Newly Available Epoxy Resin Coated Ni-Ti Wires Using Self-Ligating Brackets

2017 ◽  
Vol 2017 ◽  
pp. 1-8
Author(s):  
Hazel Garro-Piña ◽  
María Cristina Jiménez-Cervantes ◽  
Ricardo Ondarza-Rovira ◽  
Roberto Justus ◽  
Salvador García-López
Keyword(s):  
Mechanical Properties ◽  
Epoxy Resin ◽  
Clinical Management ◽  
Permanent Deformation ◽  
Applied Force ◽  
Bending Test ◽  
Recovery Cycle ◽  
Three Point Bending ◽  
Significant Difference

Aim. The purpose of this study was to evaluate the load and unload deflection and permanent deformation of round 0.016′′ and rectangular 0.016′′×0.022′′ regular and coated Ni-Ti wires. Materials and Methods. Ni-Ti archwires produced by two manufacturers were evaluated. Both regular and coated round and rectangular Ni-Ti wire segments (n=15) from each group were submitted to a three-point bending test. Both types of wires were evaluated for permanent deformation at the end of a recovery cycle. Results. The coated round 0.016′′ Ni-Ti wires produced a significantly lower force in loading (p<0.01) and unloading (p<0.01) than regular wires of the same manufacturer and size. There was no significant difference in permanent deformation between coated and regular round Ni-Ti wires from the same company. For rectangular 0.016×0.022′′ Ni-Ti wires, there was a significant difference in the loading evaluation, but the unloading test presented no significant differences. The permanent deformation of the rectangular wires revealed no significant difference between them. Conclusion. The addition of an esthetic coating to these new Ni-Ti wires produced changes in their mechanical properties, manifested as a reduction in the applied force, which should be considered in clinical management.

scholarly journals A Critical Appraisal of the Use and Properties of Nickel–Titanium Dental Alloys

Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7859
Author(s):  
Petra Močnik ◽  
Tadeja Kosec
Keyword(s):  
Metal Ions ◽  
Human Body ◽  
Niti Alloy ◽  
Nickel Titanium ◽  
Stable Steady State ◽  
Corrosion Properties ◽  
Nickel Ions ◽  
Corrosion Resistant Alloy ◽  
Subsequent Effect ◽  
Niti Wires

Nickel–titanium (NiTi) archwires are used in dentistry for orthodontic treatment. NiTi alloys have favourable mechanical characteristics, such as superelasticity and shape memory, and are also known as a corrosion-resistant alloy. In specific cases, an archwire could be attacked by certain types of corrosion or wear degradation, which can cause the leaching of metal ions and a hypersensitive response due to increased concentrations of Ni in the human body. A systematic search of the literature retrieved 102 relevant studies. The review paper focuses on three main fields: (i) electrochemical properties of NiTi wires and the effect of different environments on the properties of NiTi wires (fluoride and low pH); (ii) tribocorrosion, a combination of chemical and mechanical wear of the material, and (iii) the biocompatibility of NiTi alloy and its subsequent effect on the human body. The review showed that corrosion properties are affected by microstructure, pH of saliva and the presence of fluorides. A high variation in published results should be, therefore, interpreted with care. The release of nickel ions was assessed using the same unit, showing that the vast majority of metal ions were released in the first few days of exposure, then a stable, steady state was reached. In tribocorrosion studies, the increased concentrations of Ni ions were reported.

Sign in / Sign up

Export Citation Format

Share Document