Mechanical analysis of the improved superelastic Ni-Ti alloy wire using the orthodontic simulator with high-precision sensors

The authors have been using improved superelastic Nickel-Titanium alloy wire (ISW) to close and align extraction spaces simultaneously, instead of separately using rigid wires for closing extraction spaces and Ni–Ti alloy wires for leveling and aligning. ISW has a low stiffness, which makes it chall...

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Published inJournal of the mechanical behavior of biomedical materials Vol. 142; p. 105861
Main Authors Mikami, Naoaki, Yonemitsu, Ikuo, Takemura, Hiroshi, Kondou, Mark, Soga, Kouhei, Suga, Kazuhiro, Kanno, Zuisei, Lai, WeiJen, Uo, Motohiro, Ono, Takashi
Format Journal Article
LanguageEnglish
Published Netherlands Elsevier Ltd 01.06.2023
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Summary:The authors have been using improved superelastic Nickel-Titanium alloy wire (ISW) to close and align extraction spaces simultaneously, instead of separately using rigid wires for closing extraction spaces and Ni–Ti alloy wires for leveling and aligning. ISW has a low stiffness, which makes it challenging to generate sufficient moments. This study aimed to demonstrate the forces and moments exerted on adjacent brackets using an orthodontic simulator (OSIM) attached to a high-precision 6-axis sensor. In experiment 1, a 0.016 × 0.022-inch ISW, stainless steel (SS) wire, and β-titanium wires were ligatured into the two brackets. The 0.018 × 0.025-inch slot self-ligating brackets were bonded to two simulated teeth at the same height, and the experiment was conducted using the high-precision OSIM. The distance between the brackets was 10 mm, the V-bend angles of the installed wires were 10°, 20°, 30°, and 40°, and the apex position was set at the center of the bracket. In experiment 2, 6.0- and 9.0-mm long elastomeric chains were placed on the same brackets as in Experiment 1 to measure forces and moments. The distance between the brackets was increased by 1.0 mm from 6.0 to 15.0 mm. Both experiments were conducted in a 37 °C thermostatic chamber similar to the oral environment. In experiment 1, we measured moments on both sides for all the wires. As the V-bend angle increased, the absolute values of the moments also increased. With a V-bend angle of 10°, there was a significant (p < 0.05) difference in the moment generated in the left and right brackets among the three wire types. In the ISW, −1.67 ± 0.38 N・mm was generated in the left bracket, while 0.38 ± 0.26 N・mm was generated in the right bracket at 10°. At 20°, −1.77 ± 0.69 N・mm was generated in the left bracket, while 2.37 ± 0.94 N・mm was generated in the right bracket. At 30°, −2.98 ± 0.49 N・mm was generated in the left bracket, while 3.25 ± 0.32 N・mm was generated in the right bracket. Moreover, at 40°, −3.96 ± 0.58 N・mm was generated in the left bracket, while 3.55 ± 0.53 N・mm was generated in the right bracket. Furthermore, in experiment 2, the moments increased in proportion to the increase in distance between the centers of the two brackets. Absolute values of the moments were approximately equal for the left and right brackets. The 6.0-mm elastomeric chain generated a minimum force of −0.09 ± 0.05 N in the left direction when the distance between brackets was 6.0 mm, while a maximum of 1.24 ± 0.3 N when the distance between brackets was 12 mm in the right bracket. In the left bracket, minimum and maximum forces of −0.09 ± 0.07 and 1.3 ± 0.4 N were generated in the right direction, respectively. The 9.0-mm elastomeric chain generated a minimum force of 0.03 ± 0.07 N in the left direction when the distance between brackets was 9.0 mm, while a maximum of 1.3 ± 0.1 N when the distance between brackets was 15 mm in the right bracket. In the left bracket, minimum and maximum forces of 0.05 ± 0.06 and 0.98 ± 0.2 N were generated in the right direction, respectively. Mechanical data of the ISW have been collected in the study, which was previously difficult to perform owing to the low stiffness of the wire. It is suggested that the ISW can provide sufficient moments with the addition of V-bends to close the space by bodily movement. •We have been using the improved superelastic Nickel-Titanium alloy wire (ISW).•ISW has been used in orthodontics for leveling, alignment, and space closing.•ISW has a low stiffness, and adjustments were made to the wires and brackets.•Orthodontic simulator (OSIM) attached to a high-precision 6-axis sensor was used.•ISW can provide sufficient moments with the addition of appropriate V-bends.
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content type line 23
ISSN:1751-6161
1878-0180
DOI:10.1016/j.jmbbm.2023.105861