Forces produced by different nonconventional bracket or ligature systems during alignment of apically displaced teeth

Angle Orthod. 2009 May;79(3):533-9. doi: 10.2319/050508-249.1.


Objective: To analyze the forces released by four types of passive stainless steel self-ligating brackets (SLBs), and by two nonconventional elastomeric ligature-bracket systems when compared with conventional elastomeric ligatures on conventional stainless steel brackets during the alignment of apically displaced teeth at the maxillary arch.

Materials and methods: An experimental model consisting of five brackets was used to assess the forces released by the seven different ligature-bracket systems with 0.012'' or 0.014'' superelastic nickel titanium wire in the presence of different amounts of apical displacement of the canine (ranging from 1.5 mm to 6 mm). Comparisons between the different types of bracket/wire/ ligature systems were carried out by means of ANOVA on ranks with Dunnett's post hoc test (P < .05).

Results: When correction of a misalignment greater than 3 mm is attempted, a noticeable amount of force for alignment is generated by passive SLBs and nonconventional elastomeric ligature-bracket systems, and a null amount of force is released in the presence of conventional elastomeric ligatures on conventional brackets.

Conclusions: When minimal apical displacement is needed (1.5 mm), the differences in performance between low-friction and conventional systems are minimal. These differences become significant when correction of a misalignment of greater than 3.0 mm is attempted.

Publication types

  • Comparative Study

MeSH terms

  • Biomechanical Phenomena
  • Cuspid / pathology
  • Dental Alloys / chemistry
  • Elastomers / chemistry
  • Friction
  • Humans
  • Materials Testing
  • Maxilla
  • Nickel / chemistry
  • Orthodontic Appliance Design
  • Orthodontic Brackets*
  • Orthodontic Wires*
  • Stainless Steel / chemistry
  • Stress, Mechanical
  • Titanium / chemistry
  • Tooth Movement Techniques / instrumentation*
  • Tooth Movement Techniques / methods


  • Dental Alloys
  • Elastomers
  • titanium nickelide
  • Stainless Steel
  • Nickel
  • Titanium