Orthodontic Research Today is a free monthly online journal that collates and summarizes the latest research about Orthodontic, including details on braces, retainers, treatment. | ||||||||
|
Influence of interbracket distances on the resistance to sliding of orthodontic appliances.Whitley JQ, Kusy RP Dental Research Center, School of Dentistry, University of North Carolina, Chapel Hill, NC 27599-7455, USA. INTRODUCTION: The influence of interbracket distance (IBD) on the resistance to sliding (RS) was evaluated. METHODS: Commercially pure titanium brackets (CP-Ti; 0.018- and 0.022-in slots, width = 0.14-in) were tested against 0.016 x 0.022-in rectangular stainless steel (SS), nickel titanium (Ni-Ti), and beta-titanium (beta-Ti) archwires in the dry and wet (human saliva) states. With a custom testing apparatus that simulated a 3-bracket system, the RS was measured at a normal force of 300 cN and at second-order angles (theta) ranging from -9 degrees to +9 degrees. Twenty-three pairs of IBDs (written as IBD1_IBD2) were varied to simulate clinically relevant biomechanical scenarios with IBD ranging from 16 to 7 mm. RESULTS: In the dry state, the kinetic frictional coefficients (micro(k)) were equal to 0.12, 0.23, and 0.24 for the SS, Ni-Ti, and beta-Ti archwires against the CP-Ti brackets, respectively. The presence of saliva slightly increased micro(k). The RS was inversely proportional to the total IBD (IBD(T) = IBD1 + IBD2) regardless of archwire alloy or bracket slot. Elastic binding (BI = RS - frictional force in the passive region) did not depend on the order of the IBDs in the IBD1_IBD2 pair. CONCLUSIONS: For a specific archwire-bracket couple, the BI of an IBD1_IBD2 pair is equal to any other pair with an equal IBD(T). Although no significant difference was found between the coefficients of binding (micro(BI)) for SS and beta-Ti archwires, the micro(BI)'s of Ni-Ti archwires were lower and significantly different. The micro(BI) was linearly related (P<.01) to IBD(T) and total archwire beam length (L(T)). Published 10 September 2007 in Am J Orthod Dentofacial Orthop, 132(3): 360-72.
© 2005-2008 Orthodontic Research Today. All Rights Reserved. |
| ||||||
