Veltri Mario, Balleri Beatrice, Goracci Cecilia, Giorgetti Roberto, Balleri Piero, Ferrari Marco
Department of Dental Materials, School of Dental Medicine, University of Siena, Policlinico Le Scotte, Siena, Italy.
Am J Orthod Dentofacial Orthop. 2009 May;135(5):642-8. doi: 10.1016/j.ajodo.2007.05.025.
Several miniscrews are available for skeletal anchorage. They have different geometries with self-drilling or self-tapping features. The aim of this study was to evaluate the soft bone primary stability of 3 different orthodontic screws by using the resonance frequency analysis.
Aarhus mini-implant (Aarhus Mini-implant, Charlottenlund, Denmark) (A), Mini Spider Screws (HDC, Sarcedo, Italy) (S), and Micerium Anchorage System (Micerium, Avegno, Italy) (MAS) were investigated. To be compatible with the device used for resonance frequency analysis, the screws were modified (an abutment [Astra Tech, Mölndal, Sweden] was soldered on top). Four screws per system were tested. Each screw was placed in 5 excised rabbit femoral condyles, providing experimental models of soft bone. Placement was drill-free for the A screw, whereas the MAS and S screws required a pilot hole through the cortical layer. After each placement procedure, resonance frequency was assessed as a parameter of primary stability. Differences among the systems were analyzed by using analysis of variance for repeated measures, with the level of significance at P < 0.05.
The recorded resonance frequencies (in Hz) were (mean +/- SD): MAS, 6236.1 +/- 192.1; S, 6270.1 +/- 99.7; and A, 6193.1 +/- 142.4. Differences among the groups were not statistically significant (P > 0.05).
The resonance frequency analysis is applicable to comparatively assess the primary stability of orthodontic miniscrews. The 3 systems had similar outcomes in an experimental model of soft bone.
有几种微型螺钉可用于骨骼锚固。它们具有不同的几何形状，具备自钻或自攻特性。本研究的目的是通过共振频率分析评估3种不同正畸螺钉在软质骨中的初始稳定性。
对奥胡斯微型种植体（奥胡斯微型种植体，丹麦夏洛滕隆德）（A）、迷你蜘蛛螺钉（意大利萨尔切多HDC公司）（S）和米塞里姆锚固系统（意大利阿韦尼奥米塞里姆公司）（MAS）进行研究。为了与用于共振频率分析的设备兼容，对螺钉进行了改良（在顶部焊接一个基台[瑞典莫恩达尔阿斯特拉技术公司]）。每个系统测试4枚螺钉。将每枚螺钉植入5个切除的兔股骨髁中，形成软质骨的实验模型。A螺钉植入时无需钻孔，而MAS和S螺钉需要钻一个穿过皮质层的引导孔。每次植入操作后，评估共振频率作为初始稳定性参数。采用重复测量方差分析来分析各系统之间的差异，显著性水平为P < 0.05。
记录的共振频率（单位为Hz）为（均值±标准差）：MAS，6236.1±192.1；S，6270.1±99.7；A，6193.1±142.4。各组之间的差异无统计学意义（P > 0.05）。
共振频率分析适用于比较评估正畸微型螺钉的初始稳定性。在软质骨实验模型中，这3种系统的结果相似。
