Comparison of frictional forces between orthodontic brackets and archwires

Suh, Chung Whan; Jung, Hye Seung; Cho, Jin Hyoung; Kang, Kyung Hwa

Abstract

The object of this study was to evaluate how friction that occurs during the sliding movement of an orthodontic archwire through orthodontic brackets is differently affected by variant designs and ingredients of brackets and archwires and bracket-archwire angles. In order to simulate the situations which could occur during orthodontic treatment with fixed appliances, 4 types of brackets (Gemini(R), a stainless steel twin bracket; Mini Uni-Twin(R), a stainless steel bracket with a single bracket design and narrow mesio-distal width; Clarity(R), a metal-reinforced ceramic bracket; Transcend(R), a ceramic bracket) and 3 types of orthodontic archwires (0.016", 0.016 x 0.022" stainless steel, 0.016" Nitinol) were used and the bracket-archwire angles were controlled as 0 degrees, 3 degrees, 6 degrees, and 9 degrees, Gemini(R) significantly showed the lowest static and kinetic frictions (P < 0.001). Clarity showed the highest static and kinetic frictions with a bracket-archwire angle of 0 degrees, and Transcend at 6 degrees and 9 degrees (P < 0.001). An 0.016 x 0.022" stainless steel rectangular archwire significantly showed the highest static and kinetic frictions (P < 0.01). The lowest static and kinetic frictions were observed when the bracket-archwire angles were 0 degrees and 3 degrees with 0.016" stainless steel round archwires (P < 0.01), and 6 degrees and 9 degrees with 0.016 Nitinol (P < 0.001). The static and kinetic frictions were increased as the bracket-archwire angles were increased (P < 0.001).