Effects of prestretch on stress relaxation and permanent deformation of orthodontic synthetic elastomeric chains

Jee Hae Chang, ChungJu Hwang, Kyungho Kim, Jung Yul Cha, Kwangmahn Kim, Hyung Seog Yu

Research output: Contribution to journalArticle

Abstract

Objective: This study was performed to investigate an appropriate degree of prestretch for orthodontic synthetic elastomeric chains focusing on time-dependent viscoelastic properties. Methods: Orthodontic synthetic elastomeric chains of two brands were prestretched to 50, 100, 150, and 200% of the original length in one and three cycles, and the hysteresis areas of the obtained stress-strain curves were determined. Acrylic plates were employed to maintain constant strain during the experiment. A total of 180 samples were classified into nine groups according to brand, and their stresses and permanent deformations were measured immediately after prestretch (0 hour), after 1 hour and 24 hours, and after 1, 2, 3, 4, 5, 6, 7, and 8 weeks. The relationship between stress relaxation and permanent deformation was investigated for various degrees of prestretch, and the estimated stress resulting from tooth movement was calculated. Results: The degree of prestretch and the stress relaxation ratio exhibited a strong negative correlation, whereas no correlation was found between the degree of prestretch and the average normalized permanent strain. The maximal estimated stress was observed when prestretch was performed in three cycles to 200% of the original length. Conclusions: Although prestretch benefited residual stress, it did not exhibit negative effects such as permanent deformation. The maximal estimated stress was observed at the maximal prestretch, but the difference between prestretch and control groups decreased with time. In general, higher residual stresses were observed for product B than for product A, but this difference was not clinically significant.

Original languageEnglish
Pages (from-to)384-394
Number of pages11
JournalKorean Journal of Orthodontics
Volume48
Issue number6
DOIs
Publication statusPublished - 2018 Nov 1

Fingerprint

Orthodontics
Tooth Movement Techniques
Control Groups
elastomeric

All Science Journal Classification (ASJC) codes

  • Orthodontics

Cite this

@article{a576c92aca8b4fd58341848dd15aaa94,
title = "Effects of prestretch on stress relaxation and permanent deformation of orthodontic synthetic elastomeric chains",
abstract = "Objective: This study was performed to investigate an appropriate degree of prestretch for orthodontic synthetic elastomeric chains focusing on time-dependent viscoelastic properties. Methods: Orthodontic synthetic elastomeric chains of two brands were prestretched to 50, 100, 150, and 200{\%} of the original length in one and three cycles, and the hysteresis areas of the obtained stress-strain curves were determined. Acrylic plates were employed to maintain constant strain during the experiment. A total of 180 samples were classified into nine groups according to brand, and their stresses and permanent deformations were measured immediately after prestretch (0 hour), after 1 hour and 24 hours, and after 1, 2, 3, 4, 5, 6, 7, and 8 weeks. The relationship between stress relaxation and permanent deformation was investigated for various degrees of prestretch, and the estimated stress resulting from tooth movement was calculated. Results: The degree of prestretch and the stress relaxation ratio exhibited a strong negative correlation, whereas no correlation was found between the degree of prestretch and the average normalized permanent strain. The maximal estimated stress was observed when prestretch was performed in three cycles to 200{\%} of the original length. Conclusions: Although prestretch benefited residual stress, it did not exhibit negative effects such as permanent deformation. The maximal estimated stress was observed at the maximal prestretch, but the difference between prestretch and control groups decreased with time. In general, higher residual stresses were observed for product B than for product A, but this difference was not clinically significant.",
author = "Chang, {Jee Hae} and ChungJu Hwang and Kyungho Kim and Cha, {Jung Yul} and Kwangmahn Kim and Yu, {Hyung Seog}",
year = "2018",
month = "11",
day = "1",
doi = "10.4041/kjod.2018.48.6.384",
language = "English",
volume = "48",
pages = "384--394",
journal = "Korean Journal of Orthodontics",
issn = "2234-7518",
publisher = "Korean Association of Orthodontists",
number = "6",

}

Effects of prestretch on stress relaxation and permanent deformation of orthodontic synthetic elastomeric chains. / Chang, Jee Hae; Hwang, ChungJu; Kim, Kyungho; Cha, Jung Yul; Kim, Kwangmahn; Yu, Hyung Seog.

In: Korean Journal of Orthodontics, Vol. 48, No. 6, 01.11.2018, p. 384-394.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Effects of prestretch on stress relaxation and permanent deformation of orthodontic synthetic elastomeric chains

AU - Chang, Jee Hae

AU - Hwang, ChungJu

AU - Kim, Kyungho

AU - Cha, Jung Yul

AU - Kim, Kwangmahn

AU - Yu, Hyung Seog

PY - 2018/11/1

Y1 - 2018/11/1

N2 - Objective: This study was performed to investigate an appropriate degree of prestretch for orthodontic synthetic elastomeric chains focusing on time-dependent viscoelastic properties. Methods: Orthodontic synthetic elastomeric chains of two brands were prestretched to 50, 100, 150, and 200% of the original length in one and three cycles, and the hysteresis areas of the obtained stress-strain curves were determined. Acrylic plates were employed to maintain constant strain during the experiment. A total of 180 samples were classified into nine groups according to brand, and their stresses and permanent deformations were measured immediately after prestretch (0 hour), after 1 hour and 24 hours, and after 1, 2, 3, 4, 5, 6, 7, and 8 weeks. The relationship between stress relaxation and permanent deformation was investigated for various degrees of prestretch, and the estimated stress resulting from tooth movement was calculated. Results: The degree of prestretch and the stress relaxation ratio exhibited a strong negative correlation, whereas no correlation was found between the degree of prestretch and the average normalized permanent strain. The maximal estimated stress was observed when prestretch was performed in three cycles to 200% of the original length. Conclusions: Although prestretch benefited residual stress, it did not exhibit negative effects such as permanent deformation. The maximal estimated stress was observed at the maximal prestretch, but the difference between prestretch and control groups decreased with time. In general, higher residual stresses were observed for product B than for product A, but this difference was not clinically significant.

AB - Objective: This study was performed to investigate an appropriate degree of prestretch for orthodontic synthetic elastomeric chains focusing on time-dependent viscoelastic properties. Methods: Orthodontic synthetic elastomeric chains of two brands were prestretched to 50, 100, 150, and 200% of the original length in one and three cycles, and the hysteresis areas of the obtained stress-strain curves were determined. Acrylic plates were employed to maintain constant strain during the experiment. A total of 180 samples were classified into nine groups according to brand, and their stresses and permanent deformations were measured immediately after prestretch (0 hour), after 1 hour and 24 hours, and after 1, 2, 3, 4, 5, 6, 7, and 8 weeks. The relationship between stress relaxation and permanent deformation was investigated for various degrees of prestretch, and the estimated stress resulting from tooth movement was calculated. Results: The degree of prestretch and the stress relaxation ratio exhibited a strong negative correlation, whereas no correlation was found between the degree of prestretch and the average normalized permanent strain. The maximal estimated stress was observed when prestretch was performed in three cycles to 200% of the original length. Conclusions: Although prestretch benefited residual stress, it did not exhibit negative effects such as permanent deformation. The maximal estimated stress was observed at the maximal prestretch, but the difference between prestretch and control groups decreased with time. In general, higher residual stresses were observed for product B than for product A, but this difference was not clinically significant.

UR - http://www.scopus.com/inward/record.url?scp=85057465081&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85057465081&partnerID=8YFLogxK

U2 - 10.4041/kjod.2018.48.6.384

DO - 10.4041/kjod.2018.48.6.384

M3 - Article

VL - 48

SP - 384

EP - 394

JO - Korean Journal of Orthodontics

JF - Korean Journal of Orthodontics

SN - 2234-7518

IS - 6

ER -