Effect of wire size on maxillary arch force/couple systems for a simulated high canine malocclusion.
OBJECTIVE
To better understand the effects of copper nickel titanium (CuNiTi) archwire size on bracket-archwire mechanics through the analysis of force/couple distributions along the maxillary arch. The hypothesis is that wire size is linearly related to the forces and moments produced along the arch.


METHODS
An Orthodontic Simulator was utilized to study a simplified high canine malocclusion. Force/couple distributions produced by passive and elastic ligation using two wire sizes (Damon 0.014 and 0.018 inch) measured with a sample size of 144.


RESULTS
The distribution and variation in force/couple loading around the arch is a complicated function of wire size. The use of a thicker wire increases the force/couple magnitudes regardless of ligation method. Owing to the non-linear material behaviour of CuNiTi, this increase is less than would occur based on linear theory as would apply for stainless steel wires.


CONCLUSIONS
The results demonstrate that an increase in wire size does not result in a proportional increase of applied force/moment. This discrepancy is explained in terms of the non-linear properties of CuNiTi wires. This non-proportional force response in relation to increased wire size warrants careful consideration when selecting wires in a clinical setting.
Department of Dentistry, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alta, Canada.
Paul W
PW
Major
Faculty of Engineering, University of Alberta, Edmonton, Alta, Canada.
Roger W
RW
Toogood
Department of Dentistry, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alta, Canada.
Hisham M
HM
Badawi
Faculty of Engineering, University of Alberta, Edmonton, Alta, Canada.
Jason P
JP
Carey
Department of Dentistry, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alta, Canada.
Surbhi
S
Seru
D001696:Biomechanical Phenomena; D003300:Copper / Q000737:chemistry; D003481:Cuspid / Q000473:pathology*; D003722:Dental Alloys / Q000737:chemistry; D003724:Dental Arch / Q000473:pathology*; D004548:Elasticity; D006801:Humans; D008310:Malocclusion / Q000628:therapy*; D008437:Maxilla / Q000473:pathology*; D009532:Nickel / Q000737:chemistry; D017711:Nonlinear Dynamics; D016382:Orthodontic Appliance Design; D009969:Orthodontic Wires; D013314:Stress, Mechanical; D014025:Titanium / Q000737:chemistry; D014087:Tooth Movement Techniques / Q000295:instrumentation*
C415948:Copper NiTi; D003722:Dental Alloys; D003300:Copper; D009532:Nickel; D014025:Titanium
Elastic ligation; NiTi wires; orthodontic brackets; passive ligation