Document Type
Article
Language
eng
Format of Original
10 p.
Publication Date
7-2016
Publisher
Elsevier
Source Publication
Dental Materials
Source ISSN
0109-5641
Original Item ID
DOI: 10.1016/j.dental.2016.03.017; PubMed Central: PMID: 27183921
Abstract
Objectives
The purpose of this study was to investigate the suitability of the Bend and Free Recovery (BFR) method as a standard test method to determine the transformation temperatures of heat-activated Ni-Ti orthodontic archwires. This was done by determining the transformation temperatures of two brands of heat-activated Ni-Ti orthodontic archwires using the both the BFR method and the standard method of Differential Scanning Calorimetry (DSC). The values obtained from the two methods were compared with each other and to the manufacturer-listed values.
Methods
Forty heat-activated Ni-Ti archwires from both Rocky Mountain Orthodontics (RMO) and Opal Orthodontics (Opal) were tested using BFR and DSC. Round (0.016 inches) and rectangular (0.019 × 0.025 inches) archwires from each manufacturer were tested. The austenite start temperatures (As) and austenite finish temperatures (Af) were recorded.
Results
For four of the eight test groups, the BFR method resulted in lower standard deviations than the DSC method, and, overall, the average standard deviation for BFR testing was slightly lower than for DSC testing. Statistically significant differences were seen between the transformation temperatures obtained from the BFR and DSC test methods. However, the Af temperatures obtained from the two methods were remarkably similar with the mean differences ranging from 0.0 to 2.1 °C: Af Opal round (BFR 26.7 °C, DSC 27.6 °C) and rectangular (BFR 27.6 °C, DSC 28.6 °C); Af RMO round (BFR 25.5 °C, DSC 25.5 °C) and rectangular (BFR 28.0 °C, DSC 25.9 °C). Significant differences were observed between the manufacturer-listed transformation temperatures and those obtained with BFR and DSC testing for both manufacturers.
Significance
The results of this study suggest that the Bend and Free Recovery method is suitable as a standard method to evaluate the transformation temperatures of heat-activated Ni-Ti orthodontic archwires.
Recommended Citation
Obaisi, Noor Aminah; Galang-Boquieren, Maria Therese S.; Evans, Carla A.; Tsay, Tzong Guang Peter; Viana, Grace; Berzins, David W.; and Megremis, Spiro, "Comparison of The Transformation Temperatures of Heat-Activated Nickel-Titanium Orthodontic Archwires By Two Different Techniques" (2016). School of Dentistry Faculty Research and Publications. 185.
https://epublications.marquette.edu/dentistry_fac/185
Comments
Accepted version. Dental Materials, Vol. 32, No. 7 (July 2016): 879-888. DOI. © 2016 The Academy of Dental Materials. Published by Elsevier Ltd. Used with permission.