在干燥和潮湿状态下，针对带有二级角度的不锈钢和β钛弓丝测试钛托槽的滑动阻力。
Resistance to sliding of titanium brackets tested against stainless steel and beta-titanium archwires with second-order angulation in the dry and wet states.
作者信息
Whitley John Q, Kusy Robert P
机构信息
Dental Research Center, School of Dentistry, University of North Carolina, Chapel Hill 27599-7455, USA.
出版信息
Am J Orthod Dentofacial Orthop. 2007 Mar;131(3):400-11. doi: 10.1016/j.ajodo.2005.07.019.
INTRODUCTION
With the increased awareness of Ni allergies, alternative alloys for orthodontic products must be identified. The properties of these new products must be determined.
METHODS
Rectangular (0.017 x 0.025 in) stainless steel (SS) and beta-titanium (beta-Ti) archwires were tested against commercially pure titanium brackets (CP-Ti, 0.018-in slot) in the dry state and with whole human saliva. Resistance to sliding (RS) was measured as a function of 5 normal forces (N, 200 to 950 cN), 32 angles (theta, -12 degrees to +12 degrees), and 1 interbracket distance (IBD, 18 mm).
RESULTS
With clearance between the archwire and the bracket (passive region, theta < or =theta(c)), the frictional coefficients (mu) of the SS archwire and the CP-Ti bracket couples were 0.12 and 0.13 for the dry and wet tests, respectively; for the beta-Ti archwire and the CP-Ti bracket couples, the mu values were 0.29 and 0.28 for the dry and wet tests, respectively. For an theta without clearance (active region, theta > or =theta(c)), RS increased as a function of theta and N. To examine the rates of binding (mu(BI)) in this active region, the value of classical friction (mean of the passive region data) was subtracted from RS to yield BI, and the value of theta(c) was subtracted from each theta to yield relative contact angles (theta(r)). Because of the unique relationship between the frictional and mechanical properties of these SS and beta-Ti archwires tested against the CP-Ti brackets at a large IBD, the mu(BI) values for these archwire-bracket couples were nominally equivalent (24 to 30 cN per degree). Clinical outcomes would be unaffected by this 6 cN per degree (approximately 0.2 oz-force per degree) difference. When all kinetic data in the elastic region (theta(r) < or =5 degrees ) were combined, mu(BI) equaled 28 cN per degree. Above this region (theta(r) > or =5 degrees ), the data for the SS archwire and CP-Ti bracket couples were less scattered than those for the beta-Ti archwire and the CP-Ti bracket couples. This demarcation from linearity was designated as theta(z) and indicated the end of the elastic region and the beginning of the plastic region, above which sliding can eventually cease. This region (theta > or =theta(z)), the binding region (theta(c) < or =theta < or =theta(z)), and the classical friction region (theta < or =theta(c)) were described in a model.
CONCLUSIONS
This model explains, in part, the equivalent values of mu(BI) for SS and beta-Ti archwires tested against CP-Ti brackets.
引言
随着对镍过敏认识的提高，必须确定正畸产品的替代合金。这些新产品的性能必须加以测定。
方法
对矩形（0.017×0.025英寸）不锈钢（SS）和β钛（β-Ti）弓丝与商业纯钛托槽（CP-Ti，0.018英寸槽）在干燥状态及全人类唾液中进行测试。滑动阻力（RS）作为5种法向力（N，200至950厘牛）、32个角度（θ，-12度至+12度）和1个托槽间距（IBD，18毫米）的函数进行测量。
结果
在弓丝与托槽之间存在间隙时（被动区域，θ≤θ(c)），SS弓丝与CP-Ti托槽组合在干燥和湿润测试中的摩擦系数（μ）分别为0.12和0.13；对于β-Ti弓丝与CP-Ti托槽组合，干燥和湿润测试中的μ值分别为0.29和0.28。对于无间隙的θ（主动区域，θ≥θ(c)），RS随θ和N的函数增加。为了研究该主动区域中的结合率（μ(BI)），从RS中减去经典摩擦值（被动区域数据的平均值）以得到BI，并从每个θ中减去θ(c)的值以得到相对接触角（θ(r)）。由于在大IBD下测试的这些SS和β-Ti弓丝与CP-Ti托槽之间摩擦和力学性能的独特关系，这些弓丝-托槽组合的μ(BI)值名义上相等（每度24至30厘牛）。每度6厘牛（约每度0.2盎司力）的差异不会影响临床结果。当弹性区域（θ(r)≤5度）中的所有动力学数据合并时，μ(BI)等于每度28厘牛。在该区域之上（θ(r)≥5度），SS弓丝与CP-Ti托槽组合的数据比β-Ti弓丝与CP-Ti托槽组合的数据分散性小。这种与线性的分界被指定为θ(z)，并表示弹性区域的结束和塑性区域的开始在此之上滑动最终可能停止。该区域（θ≥θ(z)）、结合区域（θ(c)≤θ≤θ(z)）和经典摩擦区域（θ≤θ(c)）在一个模型中进行了描述。
结论
该模型部分解释了针对CP-Ti托槽测试的SS和β-Ti弓丝的μ(BI)等效值。
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