Walter Andre, Wendl Brigitte, Ploder Oliver, Mojal Sergi, Puigdollers Andreu
Department of Orthodontics and Dentofacial Orthopaedics, School of Dentistry, Universitat Internacional de Catalunya, Barcelona, Spain.
Department of Clinical Orthodontics, Medical University Clinic, Graz, Austria.
Eur J Orthod. 2017 Feb;39(1):76-84. doi: 10.1093/ejo/cjw016. Epub 2016 Apr 1.
The aim was to test which component [wire arm, connecting abutment attachment, and orthodontic mini-implant (OMI)] of the force-transmitting system (FTS) in the anterior palate of three commonly used hybrid expanders (HEs; WILMES-HE, LUDWIG-HE, and WINSAUER-HE) deforms under increasing load.
Crude single and double wire arms were tested individually. Non-opening of the maxillae halves was simulated in artificial bone blocks with single wire and double wire FTS specimens. OMIs were inserted 8mm and underwent 6mm of continuous static lateral loading. Deformation angles were measured (X-ray, n = 6) at 0, 3 and 6mm feed. OMIs and abutments were scan electron microscope (SEM) evaluated.
After 1.0mm of loading, the single wire arm of all FTS deformed between 63.4 (16.5) N and 76.2 (18.4) N, and the double wire arm of reinforced FTS (wires positioned 'side by side') deformed after 1.0mm between 110.0 (18.4) N and 134.8 (22.3) N. The crude single wire resisted 89 (5.1) N until plastic deformation, whereas the crude double wire positioned 'on top of each other' resisted 438 (21.3) N. At 6mm loading, the reinforced WINSAUER-HE FTS withstood a maximum load of 320.9 (31.1) N and the reinforced LUDWIG-HE FTS 19% less, both under great deformation of double wires and OMIs. The screw-fixated WILMES-HE FTS abutment attachment (overlapping OMI head 34%) detached around 250N. The bonded WINSAUER-HE and LUDWIG-HE abutment attachments did not detach. Nor did the modified bonded plus the modified screw-fixated WILMES-HE abutment attachment when overlapping 100%.
Early OMI and single wire arm deformation in HEs are crucial for unsuccessful RME in more mature maxillae. Double wire arms should be obligatory. OMIs with inner diameter greater 1.36mm are recommended. One hundred per cent overlapping abutment attachments do not detach.
目的是测试三种常用混合扩弓器（HEs；威尔姆斯扩弓器、路德维希扩弓器和温绍尔扩弓器）在前腭部的力传递系统（FTS）的哪个组件[钢丝臂、连接基台附件和正畸微型种植体（OMI）]在负荷增加时会发生变形。
分别对粗制单丝和双丝臂进行测试。在带有单丝和双丝FTS标本的人工骨块中模拟上颌两半未打开的情况。将OMI植入8mm，并进行6mm的连续静态侧向加载。在进给0、3和6mm时测量变形角度（X射线，n = 6）。对OMI和基台进行扫描电子显微镜（SEM）评估。
加载1.0mm后，所有FTS的单丝臂在63.4（16.5）N至76.2（18.4）N之间变形，增强FTS（钢丝“并排”放置）的双丝臂在1.0mm后在110.0（18.4）N至134.8（22.3）N之间变形。粗制单丝在89（5.1）N时出现塑性变形，而粗制双丝“叠放”时能承受438（21.3）N。在加载6mm时，增强的温绍尔扩弓器FTS承受了320.9（31.1）N的最大负荷，增强的路德维希扩弓器FTS承受的负荷少19%，此时双丝和OMI均发生较大变形。螺丝固定的威尔姆斯扩弓器FTS基台附件（OMI头部重叠34%）在约250N时分离。粘结的温绍尔扩弓器和路德维希扩弓器基台附件未分离。当重叠100%时，改良粘结加改良螺丝固定的威尔姆斯扩弓器基台附件也未分离。
混合扩弓器中早期的OMI和单丝臂变形是上颌骨较成熟时快速扩弓失败的关键因素。应强制使用双丝臂。建议使用内径大于1.36mm的OMI。100%重叠的基台附件不会分离。
