Assad-Loss Tatiana Feres, Kitahara-Céia Flávia Mitiko Fernandes, Silveira Giordani Santos, Elias Carlos Nelson, Mucha José Nelson
Universidade Federal Fluminense, Department of Orthodontics (Niterói/RJ, Brazil).
Instituto Militar de Engenharia, Materials Engineering, Biomaterials Laboratory, Rio de Janeiro, RJ, Brazil.
Dental Press J Orthod. 2017 May-Jun;22(3):47-54. doi: 10.1590/2177-6709.22.3.047-054.oar.
: This study aimed at evaluating the design and dimensions of five different brands of orthodontic mini-implants, as well as their influence on torsional fracture strength.
: Fifty mini-implants were divided into five groups corresponding to different manufactures (DEN, RMO, CON, NEO, SIN). Twenty-five mini-implants were subjected to fracture test by torsion in the neck and the tip, through arbors attached to a Universal Mechanical Testing Machine. The other 25 mini-implants were subjected to insertion torque test into blocks of pork ribs using a torquimeter and contra-angle handpiece mounted in a surgical motor. The shape of the active tip of the mini-implants was evaluated under microscopy. The non-parametric Friedman test and Snedecor's F in analysis of variance (ANOVA) were used to evaluate the differences between groups.
: The fracture torque of the neck ranged from 23.45 N.cm (DEN) to 34.82 N.cm (SIN), and of the tip ranged from 9.35 N.cm (CON) to 24.36 N.cm (NEO). Insertion torque values ranged from 6.6 N.cm (RMO) to 10.2 N.cm (NEO). The characteristics that most influenced the results were outer diameter, inner diameter, the ratio between internal and external diameters, and the existence of milling in the apical region of the mini-implant.
: The fracture torques were different for both the neck and the tip of the five types evaluated. NEO and SIN mini-implants showed the highest resistance to fracture of the neck and tip. The fracture torques of both tip and neck were higher than the torque required to insert mini-implants.
本研究旨在评估五种不同品牌正畸微型种植体的设计和尺寸，以及它们对扭转断裂强度的影响。
五十枚微型种植体被分为五组，分别对应不同制造商（DEN、RMO、CON、NEO、SIN）。二十五枚微型种植体通过连接到万能材料试验机的心轴在颈部和尖端进行扭转断裂试验。另外二十五枚微型种植体使用扭矩计和安装在手术电机上的反角手机在猪肋骨块中进行植入扭矩测试。在显微镜下评估微型种植体活性尖端的形状。采用非参数Friedman检验和方差分析（ANOVA）中的Snedecor's F检验来评估组间差异。
颈部的断裂扭矩范围为23.45 N·cm（DEN）至34.82 N·cm（SIN），尖端的断裂扭矩范围为9.35 N·cm（CON）至24.36 N·cm（NEO）。植入扭矩值范围为6.6 N·cm（RMO）至10.2 N·cm（NEO）。对结果影响最大的特征是外径、内径、内外径之比以及微型种植体根尖区域的铣削情况。
在所评估的五种类型微型种植体的颈部和尖端，断裂扭矩均有所不同。NEO和SIN微型种植体在颈部和尖端显示出最高的抗断裂能力。尖端和颈部的断裂扭矩均高于植入微型种植体所需的扭矩。
