Analysis of Frictional Forces in Orthodontic Bracket-Archwires Combinations: An Experimental Study.

In orthodontics, brackets, archwire and ligatures are used to treat the malocclusion of teeth. Archwires are the force applying component in the fixed appliances by engagement inside the bracket slot. Friction in the archwire-bracket is an important parameter affecting the magnitude of force transfer on teeth. The objective of this study was to experimentally measure the frictional forces in Stainless Steel (SS) bracket with SS, Nickel-Titanium (NiTi) superelastic, Heat activated NiTi (HANT) and Beta-Titanium (Beta-Ti) archwires. A specially designed fixture was fabricated to engage the orthodontic bracket-archwire simulating the tipping movement. For experimentation, pin on disc tribometer was used to measure the frictional forces generated by the archwires within the SS bracket. The results showed that there is increasing order of the frictional forces from the SS, NiTi superelastic, Beta-Ti to HANT archwires. Both SS bracket - archwire combinations are the best to reduce the frictional forces during up-righting and tipping during space closure. The results of this study would help clinicians to predict the frictional force of commonly used metallic archwire materials in orthodontic brackets during tipping in the fixed appliance therapy. [ABSTRACT FROM AUTHOR]