Hwang C J, Shin J S, Cha J Y
Department of Orthodontics, College of Dentistry, Yonsei University, Seoul, Korea.
Am J Orthod Dentofacial Orthop. 2001 Oct;120(4):383-91. doi: 10.1067/mod.2001.117911.
Most orthodontic appliances and archwires are stainless steel or nickel-titanium (NiTi) alloys that can release metal ions, with saliva as the medium. To measure metal released from the fixed orthodontic appliances currently in use, we fabricated simulated fixed orthodontic appliances that corresponded to half of the maxillary arch and soaked them in 50 mL of artificial saliva (pH 6.75 +/- 0.15, 37 degrees C) for 3 months. We used brackets, tubes, and bands made by Tomy (Tokyo, Japan). Four groups were established according to the appliance manufacturer and the type of metal in the .016 x .022-in archwires. Groups A and B were stainless steel archwires from Ormco (Glendora, Calif) and Dentaurum (Ispringen, Germany), respectively, and groups C and D were both NiTi archwires with Ormco's copper NiTi and Tomy's Bioforce sentalloy, respectively. Stainless steel archwires were heat treated in an electric furnace at 500 degrees C for 1 minute and quenched in water. We measured the amount of metal released from each group by immersion time. Our conclusions were as follows: (1) there was no increase in the amount of chromium released after 4 weeks in group A, 2 weeks in group B, 3 weeks in group C, and 8 weeks in group D; (2) there was no increase in the amount of nickel released after 2 weeks in group A, 3 days in group B, 7 days in group C, and 3 weeks in group D; and (3) there was no increase in the amount of iron released after 2 weeks in group A, 3 days in group B, and 1 day in groups C and D. In our 3-month-long investigation, we saw a decrease in metal released as immersion time increased.
大多数正畸矫治器和弓丝是不锈钢或镍钛（NiTi）合金，它们能以唾液为介质释放金属离子。为了测量目前正在使用的固定正畸矫治器释放的金属量，我们制作了对应上颌牙弓一半的模拟固定正畸矫治器，并将它们浸泡在50毫升人工唾液（pH 6.75±0.15，37摄氏度）中3个月。我们使用了由日本东京的Tomy公司生产的托槽、颊面管和带环。根据矫治器制造商以及0.016×0.022英寸弓丝中的金属类型，将其分为四组。A组和B组分别使用美国加利福尼亚州格伦多拉市Ormco公司和德国伊斯普林根市Dentaurum公司生产的不锈钢弓丝，C组和D组均使用NiTi弓丝，分别为Ormco公司的含铜NiTi弓丝和Tomy公司的Bioforce sentalloy弓丝。不锈钢弓丝在电炉中于500摄氏度热处理1分钟，然后在水中淬火。我们通过浸泡时间来测量每组释放的金属量。我们的结论如下：（1）A组4周后、B组2周后、C组3周后以及D组8周后，铬的释放量均未增加；（2）A组2周后、B组3天后、C组7天后以及D组3周后，镍的释放量均未增加；（3）A组2周后、B组3天后以及C组和D组1天后，铁的释放量均未增加。在我们为期3个月的研究中，我们发现随着浸泡时间的增加，金属释放量减少。
