Johnson Gerald, Walker Mary P, Kula Katherine
Department Head, Orthodontics, US Navy, Naples, Italy.
Angle Orthod. 2005 Jan;75(1):95-100. doi: 10.1043/0003-3219(2005)075<0095:FSOCBT>2.0.CO;2.
One of the most common areas of ceramic bracket fracture is within the tie-wing complex. When an archwire is ligated into position, tensile forces are placed under the tie wing. However, no study, to date, has focused specifically on the fracture resistance of the tie-wing complex. The aim of this study is to compare the tensile fracture strength of seven currently available ceramic brackets (Inspire, Fascination, Mystique, InVu, Clarity, Virage, and Luxi) as a function of bracket brand and bracket configuration, semitwin vs true-twin. Based on a power analysis of pilot data, 10 maxillary central incisor brackets per group were tested to failure with a tensile load placed directly under the distoincisal tie wing. The results ranged from a maximum mean fracture strength of 147.71 (5.87) MPa with Fascination brackets to a minimum mean fracture strength of 84.28 (7.01) MPa with Luxi brackets. The statistical analysis indicated a significant effect on fracture strength as a function of bracket brand (P < .05) and that semitwin brackets, Fascination, Mystique, and Virage, had significantly higher fracture strength than true-twin brackets, Clarity, lnVu, and Luxi (P < .05). Interestingly, the only monocrystalline bracket in the study, Inspire, could not be fractured using the investigation protocol. In fact, the steel ligature fixture wire would break before tie-wing fracture at a mean fixture failure of 198.65 MPa.
陶瓷托槽骨折最常见的部位之一是在结扎翼复合体内部。当将弓丝结扎到位时，结扎翼下方会受到拉力。然而，迄今为止，尚无研究专门关注结扎翼复合体的抗骨折性。本研究的目的是比较七种市售陶瓷托槽（Inspire、Fascination、Mystique、InVu、Clarity、Virage和Luxi）的拉伸断裂强度，作为托槽品牌和托槽构型（半孪生与全孪生）的函数。根据前期数据的功效分析，每组测试10个上颌中切牙托槽直至失效，拉伸载荷直接施加于远中切缘结扎翼下方。结果显示，Fascination托槽的最大平均断裂强度为147.71（5.87）MPa，Luxi托槽的最小平均断裂强度为84.28（7.01）MPa。统计分析表明，托槽品牌对断裂强度有显著影响（P < 0.05），半孪生托槽Fascination、Mystique和Virage的断裂强度显著高于全孪生托槽Clarity、InVu和Luxi（P < 0.05）。有趣的是，本研究中唯一的单晶托槽Inspire，按照研究方案无法使其骨折。实际上，在平均固定失效强度为198.65 MPa时，结扎固定丝会在结扎翼骨折之前断裂。
