An in vitro assessment of the mechanical characteristics of nickel-titanium orthodontic wires in Fluoride solutions with different acidities

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.

Download Full-text

DO ESTHETICS CONTRADICT WITH FUNCTION? IN VITRO ASSESSMENT OF LOAD DEFLECTION AND FRICTIONAL RESISTANCE OF COATED VERSUS UNCOATED SUPERELASTIC NICKEL-TITANIUM ARCHWIRES

Egyptian Dental Journal ◽

10.21608/edj.2017.76465 ◽

2017 ◽

Vol 63 (4) ◽

pp. 3983-3993

Author(s):

Gihan Waly

Keyword(s):

Frictional Resistance ◽

Nickel Titanium ◽

In Vitro Assessment

Download Full-text

Deflection test evaluation of different lots of the same nickel-titanium wire commercial brand

Dental Press Journal of Orthodontics ◽

10.1590/2177-6709.21.1.042-046.oar ◽

2016 ◽

Vol 21 (1) ◽

pp. 42-46 ◽

Cited By ~ 1

Author(s):

Murilo Gaby Neves ◽

Fabrício Viana Pereira Lima ◽

Júlio de Araújo Gurgel ◽

Célia Regina Maio Pinzan-Vercelino ◽

Fernanda Soares Rezende ◽

...

Keyword(s):

Elastic Properties ◽

Testing Machine ◽

In Vitro Study ◽

Nickel Titanium ◽

Orthodontic Wires ◽

Niti Wire ◽

Titanium Wire ◽

Deflection Analysis ◽

Deflection Test

Introduction: The aim of this in vitro study was to compare the elastic properties of the load-deflection ratio of orthodontic wires of different lot numbers and the same commercial brand. Methods: A total of 40 nickel-titanium (NiTi) wire segments (Morelli OrtodontiaTM - Sorocaba, SP, Brazil), 0.016-in in diameter were used. Groups were sorted according to lot numbers (lots 1, 2, 3 and 4). 28-mm length segments from the straight portion (ends) of archwires were used. Deflection tests were performed in an EMIC universal testing machine with 5-N load cell at 1 mm/minute speed. Force at deactivation was recorded at 0.5, 1, 2 and 3 mm deflection. Analysis of variance (ANOVA) was used to compare differences between group means. Results: When comparing the force of groups at the same deflection (3, 2 and 1 mm), during deactivation, no statistical differences were found. Conclusion: There are no changes in the elastic properties of different lots of the same commercial brand; thus, the use of different lots of the orthodontic wires used in this research does not compromise the final outcomes of the load-deflection ratio.

Download Full-text