fa Effects of bracket design on critical contact angle ارتودنسی Orthodontics پژوهشي Research <p> <strong>Objective</strong>:</p><p>  To explore how the position of the bracket slots relative to the archwire influences the friction between them, and how bracket design affects the critical contact angle (θc). </p><p> <strong>Materials and Methods</strong>: </p><p> Two kinds of stainless steel archwires (0.016 and 0.019 × 0.025-inch) were tested against four kinds of brackets (Transmission Straight Archwire bracket, Domestic MBT bracket, Tip-Edge Plus bracket, and BioQuick self-ligation bracket) in the dry state. Resistance to sliding (RS) was measured as an increase in contact angle (θ). The value of θc was calculated by two linear regression lines. </p><p> <strong>Results:</strong></p><p>  Friction remained stable when θ < θc, then increased linearly when θ > θc. The θc values of the Tip-Edge Plus bracket and Transmission Straight Archwire bracket were significantly larger than those for the Domestic MBT bracket and BioQuick self-ligation bracket. </p><p> <strong>Conclusions:</strong></p><p>  The relationship between the archwire and bracket slot significantly affects the resistance to sliding. The “edge-off” structure of the Tip-Edge Plus bracket and Transmission Straight Archwire bracket could help to increase the θc value, and to expand the passive configuration range. </p><hr><p></p><p> <strong>Source: </strong>The Angel Orthodontists</p><p><a href="http://www.angle.org/doi/abs/10.2319/080112-621.1" target="_blank"><font color="#0000ff"> Full Text</font></a></p> Resistance to sliding, Critical contact angle, Bracket design 0 0 http://idai.ir/browse.php?a_code=A-10-32-2025&slc_lang=fa&sid=1 Xiaomo Liu 10031947532846009500 10031947532846009500 No Department of Orthodontics, Peking University School and Hospital of Stomatology, Beijing, PR China Peng Ding 10031947532846009501 10031947532846009501 No Department of Orthodontics, Peking University School and Hospital of Stomatology, Beijing, PR China Jiuxiang Lin momo96@163.com 10031947532846009502 10031947532846009502 Yes Department of Orthodontics, Peking University School and Hospital of Stomatology, Beijing, PR China