Department of Orthodontics, Dental Branch, Islamic Azad University, Tehran, Iran.
Biol Trace Elem Res. 2012 Dec;150(1-3):15-20. doi: 10.1007/s12011-012-9457-y. Epub 2012 May 29.
Effect of long-term orthodontic treatment on salivary nickel and chromium has not been quite assessed except in few retrospective studies with controversial results. The aim of this prospective study was to measure salivary levels of these ions during 1 year of orthodontic treatment. Saliva samples were collected from 20 orthodontic patients, before treatment (control) and 6 and 12 months later. Nickel and chromium concentrations were determined using atomic absorption spectrophotometry. Data were analyzed using one- and two-way repeated-measures ANOVA, Bonferroni, Friedman (α = 0.05), and Wilcoxon signed-ranks tests (α = 0.016). Average nickel level changed from 9.75 ± 5.02 to 10.37 ± 6.94 and then to 8.32 ± 4.36 μg/L in 1 year. Average chromium concentration changed from 3.86 ± 1.34 to 4.6 ± 6.11 and then to 2.04 ± 1.66 μg/L. Alterations in nickel values were not statistically significant [P = 0.468 (ANOVA)], but fluctuations in chromium levels were [P = 0.021 (Friedman)]. The decrease in chromium concentration after 12 months was significant compared to the control [P = 0.004 (Wilcoxon)]. Although slightly increased after 6 months, the concentration of both ions dropped to levels slightly lower than the control groups after 12 months.
除了少数几项存在争议结果的回顾性研究外，长期正畸治疗对唾液中镍和铬的影响尚未得到充分评估。本前瞻性研究旨在测量正畸治疗 1 年内这些离子的唾液水平。从 20 名正畸患者中收集唾液样本，在治疗前（对照组）和 6 个月和 12 个月后各采集一次。使用原子吸收分光光度法测定镍和铬的浓度。使用单向和双向重复测量方差分析、Bonferroni、Friedman（α=0.05）和 Wilcoxon 符号秩检验（α=0.016）分析数据。镍的平均水平在 1 年内从 9.75±5.02μg/L 变为 10.37±6.94μg/L，然后变为 8.32±4.36μg/L。铬的平均浓度从 3.86±1.34μg/L 变为 4.6±6.11μg/L，然后变为 2.04±1.66μg/L。镍值的变化无统计学意义[P=0.468（方差分析）]，但铬水平的波动有统计学意义[P=0.021（Friedman）]。与对照组相比，12 个月后铬浓度的降低具有统计学意义[P=0.004（Wilcoxon）]。虽然在 6 个月后略有增加，但 12 个月后两种离子的浓度均降至略低于对照组的水平。
