The effect of thickness and deflection of orthodontic thermoplastic materials on its mechanical properties

Sam Min, Chung Ju Hwang, Hyung Seog Yu, Sang Bae Lee, Jung Yul Cha

Research output: Contribution to journalArticlepeer-review

11 Citations (Scopus)


Objective: The purposes of this study were to evaluate the force and stress depending on the type, deflection and thickness of the materials and to evaluate the mechanical properties of thermoplastic materials after repeated loading. Methods: Four types of thermoplastic products were tested. Force until the deflections of 2.0 mm and the stress when the materials were restoring to its resting position were evaluated. The mechanical properties of thermoplastic materials evaluated after 5 repeated loading cycles. Results: The interaction was observed between the thickness and the deflection (p < 0.05) from the regression equation. Thickness and amount of deflection rather than products and materials showed the largest effect on force and stress. In all products, at least 159 gf of force was required for more than 1.0 mm deflection or when materials with 1.0 mm thickness were deflected. The stress recorded was more than 19 gf/mm2. During repeated loading, each group showed significant difference on the force and the stress (p < 0.01), 10 - 17% reduction of force and 4 - 7% reduction of stress in average. Conclusions: Proper thickness of thermoplastic materials and deflection level of tooth movement should be decided for the physiologic tooth movement. Force decay after repeated loading should be considered for the efficient tooth movement.

Original languageEnglish
Pages (from-to)16-26
Number of pages11
JournalKorean Journal of Orthodontics
Issue number1
Publication statusPublished - 2010

All Science Journal Classification (ASJC) codes

  • Orthodontics


Dive into the research topics of 'The effect of thickness and deflection of orthodontic thermoplastic materials on its mechanical properties'. Together they form a unique fingerprint.

Cite this