PDF(Pubmed)
Abstract：
OBJECTIVE: This study aimed to compare the insertion torque (IT), flexural strength (FS) and surface alterations between stainless steel (SS-MIs) and titanium alloy (Ti-MIs) orthodontic mini-implants.
METHODS: Twenty-four MIs (2 x 10 mm; SS-MIs, n = 12; Ti-MIs, n = 12) were inserted on artificial bone blocks of 20 lb/ft3 (20 PCF) and 40 lb/ft3 (40 PCF) density. The maximum IT was recorded using a digital torque meter. FS was evaluated at 2, 3 and 4 mm-deflection. Surface topography and chemical composition of MIs were assessed by scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). General linear and mixed models were used to assess the effect of the MI type, bone density and deflection on the evaluated outcomes.
RESULTS: The IT of Ti-MIs was 1.1 Ncm greater than that obtained for the SS-MIs (p= 0.018). The IT for MIs inserted in 40 PCF test blocks was 5.4 Ncm greater than that for those inserted in 20 PCF test blocks (p < 0.001). SS-MIs inserted in higher density bone (40 PCF) had significantly higher flexural strength than the other groups, at 2 mm (98.7 ± 5.1 Ncm), 3 mm (112.0 ± 3.9 Ncm) and 4 mm (120.0 ± 3.4 Ncm) of deflection (p< 0.001). SEM evidenced fractures in the Ti-MIs. EDS revealed incorporation of 18% of C and 2.06% of O in the loaded SS-MIs, and 3.91% of C in the loaded Ti-MIs.
CONCLUSIONS: Based on the findings of this in vitro study, it seems that SS-MIs offer sufficient stability and exhibit greater mechanical strength, compared to Ti-MIs when inserted into higher density bone.
METHODS: Twenty-four MIs (2 x 10 mm; SS-MIs, n = 12; Ti-MIs, n = 12) were inserted on artificial bone blocks of 20 lb/ft3 (20 PCF) and 40 lb/ft3 (40 PCF) density. The maximum IT was recorded using a digital torque meter. FS was evaluated at 2, 3 and 4 mm-deflection. Surface topography and chemical composition of MIs were assessed by scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). General linear and mixed models were used to assess the effect of the MI type, bone density and deflection on the evaluated outcomes.
RESULTS: The IT of Ti-MIs was 1.1 Ncm greater than that obtained for the SS-MIs (p= 0.018). The IT for MIs inserted in 40 PCF test blocks was 5.4 Ncm greater than that for those inserted in 20 PCF test blocks (p < 0.001). SS-MIs inserted in higher density bone (40 PCF) had significantly higher flexural strength than the other groups, at 2 mm (98.7 ± 5.1 Ncm), 3 mm (112.0 ± 3.9 Ncm) and 4 mm (120.0 ± 3.4 Ncm) of deflection (p< 0.001). SEM evidenced fractures in the Ti-MIs. EDS revealed incorporation of 18% of C and 2.06% of O in the loaded SS-MIs, and 3.91% of C in the loaded Ti-MIs.
CONCLUSIONS: Based on the findings of this in vitro study, it seems that SS-MIs offer sufficient stability and exhibit greater mechanical strength, compared to Ti-MIs when inserted into higher density bone.
摘要：
目的：本研究旨在比较插入扭矩（IT），不锈钢（SS-MIs）和钛合金（Ti-MIs）正畸微型植入物之间的弯曲强度（FS）和表面变化。
方法：二十四个MIs（2x10mm；SS-MIs，n=12；Ti-MIs，n=12）插入20lb/ft3（20PCF）和40lb/ft3（40PCF）密度的人工骨块上。使用数字扭矩计记录最大IT。在2、3和4mm偏转下评估FS。通过扫描电子显微镜（SEM）和能量色散X射线光谱（EDS）评估了MI的表面形貌和化学组成。一般线性和混合模型用于评估MI类型的影响，骨密度和偏转对评估结果的影响。
结果：Ti-MIs的IT比SS-MIs的IT高1.1Ncm（p=0.018）。在40个PCF测试块中插入的MI的IT比在20个PCF测试块中插入的MI的IT大5.4Ncm（p<0.001）。插入高密度骨（40PCF）的SS-MIs的抗弯强度明显高于其他组，在2mm(98.7±5.1Ncm),3mm(112.0±3.9Ncm)和4mm(120.0±3.4Ncm)的偏转(p<0.001)。SEM证实了Ti-MIs中的断裂。EDS显示在加载的SS-MIs中掺入了18%的C和2.06%的O，和3.91%的C在负载的Ti-MIs中。
结论：根据这项体外研究的结果，似乎SS-MIs提供足够的稳定性并表现出更大的机械强度，与Ti-MI相比，当插入更高密度的骨骼。
方法：二十四个MIs（2x10mm；SS-MIs，n=12；Ti-MIs，n=12）插入20lb/ft3（20PCF）和40lb/ft3（40PCF）密度的人工骨块上。使用数字扭矩计记录最大IT。在2、3和4mm偏转下评估FS。通过扫描电子显微镜（SEM）和能量色散X射线光谱（EDS）评估了MI的表面形貌和化学组成。一般线性和混合模型用于评估MI类型的影响，骨密度和偏转对评估结果的影响。
结果：Ti-MIs的IT比SS-MIs的IT高1.1Ncm（p=0.018）。在40个PCF测试块中插入的MI的IT比在20个PCF测试块中插入的MI的IT大5.4Ncm（p<0.001）。插入高密度骨（40PCF）的SS-MIs的抗弯强度明显高于其他组，在2mm(98.7±5.1Ncm),3mm(112.0±3.9Ncm)和4mm(120.0±3.4Ncm)的偏转(p<0.001)。SEM证实了Ti-MIs中的断裂。EDS显示在加载的SS-MIs中掺入了18%的C和2.06%的O，和3.91%的C在负载的Ti-MIs中。
结论：根据这项体外研究的结果，似乎SS-MIs提供足够的稳定性并表现出更大的机械强度，与Ti-MI相比，当插入更高密度的骨骼。
