A potential new bactericide treatment for NiTi orthodontic archwires based in the electrodeposition of silver nanoparticles on the surface was studied. Twenty-five archwires were treated by electrodeposition, obtaining nanoparticles of silver embedded on the archwire surface. These were evaluated in order to investigate the possible changes on the superelastic characteristics (critical temperatures and stresses), the nickel ion release, and the bacteria culture behavior. The chemical composition was analyzed by Energy Dispersive X-Ray Spectroscopy-microanalysis; the singular temperatures of the martensitic transformation were obtained by a flow calorimeter. Induced martensitic transformation stresses were obtained by mechanical testing apparatus. Nickel ion release was analyzed by inductively coupled plasma-mass spectrometry (ICP-MS) equipment using artificial saliva solution at 37 °C. Bacterial tests were studied with the most used oral bacterial strains: Streptococcus sanguinis and Lactobacillus salivarius. NiTi samples were immersed in bacterial suspensions for 2 h at 37 °C. Adhered bacteria were separated and seeded on agar plates: Tood-Hewitt (TH) and Man-Rogosa-Sharpe (MRS) for S. sanguinis and for L.salivarius, respectively. These were then incubated at 37 °C for 1 day and the colonies were analyzed. The results showed that the transformation temperatures and the critical stresses have not statistically significant differences. Likewise, nickel ion release at different immersion times in saliva at 37 °C does not present changes between the original and treated with silver nanoparticles archwires. Bacteria culture results showed that the reduction of the bacteria due to the presence to the nanoparticles of silver is higher than 90%. Consequently, the new treatment with nanoparticles of silver could be a good candidate as bactericidic orthodontic archwire.

中文翻译：

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新型杀菌剂正畸弓丝：含银纳米粒子的NiTi

研究了基于表面纳米银电沉积的NiTi正畸弓丝潜在的新型杀菌剂处理方法。通过电沉积处理二十五个弓丝，获得嵌入弓丝表面的银纳米颗粒。对这些进行了评估，以研究超弹性特征（临界温度和应力），镍离子释放和细菌培养行为的可能变化。化学成分通过能量色散X射线光谱法-微量分析法分析。马氏体转变的奇异温度是通过流量热计获得的。通过机械测试装置获得诱导的马氏体转变应力。使用感应唾液在37°C下通过电感耦合等离子体质谱（ICP-MS）设备分析镍离子的释放。用最常用的口腔细菌菌株研究了细菌测试：血链球菌和唾液乳杆菌。将NiTi样品在37°C的细菌悬浮液中浸泡2小时。粘附的细菌分离，并接种于琼脂平板上：Tood-休伊特（TH）和曼-Rogosa-夏普（MRS）为血链球菌和L.salivarius，分别。然后将它们在37°C下孵育1天，并分析菌落。结果表明，转变温度和临界应力在统计上没有显着差异。同样，在37°C的唾液中，浸入时间不同的镍离子释放在原始纳米银弓丝和经处理的纳米银弓丝之间也没有变化。细菌培养结果表明，由于存在于银的纳米颗粒中，细菌的减少率高于90％。因此，用银纳米颗粒进行的新治疗可能是细菌正畸弓丝的良好选择。