Evaluation of torque moment in esthetic brackets from bendable alloy wires

Angle Orthod. 2021 Sep 1;91(5):656-663. doi: 10.2319/081820-729.1.

Abstract

Objectives: To examine the torque moment that occurs between esthetic brackets and bendable alloy (stainless steel [SS], titanium-molybdenum [Ti-Mo], and titanium-niobium [Ti-Nb]) wires.

Materials and methods: This study examined ceramic (CR), zirconium oxide (ZC), polycarbonate (PC), and conventional metallic brackets (MT) (upper, 0.018-inch and 0.022-inch slots) combined with SS, Ti-Mo, and Ti-Nb wires using elastic module ligation. The torque moments delivered by various wire and bracket combinations were measured using a torque gauge apparatus. The wire torque angles at 5-40° were examined.

Results: The torque value increased in the order of CR, ZC, MT, and PC brackets for both 0.018-inch and 0.022-inch slots. The fracture points of the CR and ZC brackets combined with SS and Ti-Mo wires were approximately more than 30° and 35°, respectively. No fracture points were detected in the combination of ZC brackets and Ti-Nb wires.

Conclusions: The current study identified the material characteristics of CR, ZR, and PC brackets during torque tooth movements. The present results demonstrate a characteristic combined effect between different esthetic brackets and bendable alloy wires.

Keywords: Bendable wire; Dental materials; Esthetic bracket; Fracture point; Third-order bend; Torque moment.

MeSH terms

  • Alloys
  • Dental Stress Analysis
  • Esthetics, Dental
  • Materials Testing
  • Orthodontic Appliance Design
  • Orthodontic Brackets*
  • Orthodontic Wires*
  • Stainless Steel
  • Titanium
  • Torque

Substances

  • Alloys
  • Stainless Steel
  • Titanium