Innovative design of closing loops producing an optimal force system applicable in the 0.022-in bracket slot system

Mayumi Sumi, Yoshiyuki Koga, Jun ya Tominaga, Ryo Hamanaka, Hiroya Ozaki, Pao Chang Chiang, Noriaki Yoshida

Research output: Contribution to journalArticlepeer-review

8 Citations (Scopus)


Introduction Most closing loops designed for producing higher moment-to-force (M/F) ratios require complex wire bending and are likely to cause hygiene problems and discomfort because of their complicated configurations. We aimed to develop a simple loop design that can produce optimal force and M/F ratio. Methods A loop design that can generate a high M/F ratio and the ideal force level was investigated by varying the portion and length of the cross-sectional reduction of a teardrop loop and the loop position. The forces and moments acting on closing loops were calculated using structural analysis based on the tangent stiffness method. Results An M/F ratio of 9.3 (high enough to achieve controlled movement of the anterior teeth) and an optimal force level of approximately 250 g of force can be generated by activation of a 10-mm-high teardrop loop whose cross-section of 0.019 × 0.025 or 0.021 × 0.025 in was reduced in thickness by 50% for a distance of 3 mm from the apex, located between a quarter and a third of the interbracket distance from the canine bracket. Conclusions The simple loop design that we developed delivers an optimal force and an M/F ratio for the retraction of anterior teeth, and is applicable in a 0.022-in slot system.

Original languageEnglish
Pages (from-to)968-978
Number of pages11
JournalAmerican Journal of Orthodontics and Dentofacial Orthopedics
Issue number6
Publication statusPublished - Dec 1 2016
Externally publishedYes

ASJC Scopus subject areas

  • Orthodontics


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