Department of Orthodontics, Faculty of Dental Sciences, Sir Ramachandra Medical College, Chennai, India.
Am J Orthod Dentofacial Orthop. 2011 Sep;140(3):383-8. doi: 10.1016/j.ajodo.2010.07.027.
The release of metal ions from fixed orthodontic appliances is a source of concern. The aim of this study was to evaluate genotoxic damage in the oral mucosal cells of patients wearing fixed appliance, and the nickel and chromium ion contents in these cells.
Twenty patients undergoing orthodontic treatment formed the experimental group, and 20 untreated subjects comprised the control group. Oral mucosal smears were collected at 2 times: at debonding and 30 days after debonding. The smears were stained with Papanicolaou stain and studied under a light microscope to evaluate the presence of micronuclei. Inductively coupled plasma-mass spectrometry was used to quantify the presence of metal ions. The data were subjected to the Mann-Whitney U test and the Spearman rank correlation test.
The mean micronuclei frequency was significantly higher in the treated group than in the control group at debonding; the difference was smaller and not statistically significant 30 days after debonding. The nickel and chromium ion contents in the experimental group were not significantly higher than in the control group. No correlation could be established between micronuclei frequency and metal ion content.
Nickel and chromium alloys of orthodontic appliances emit metal ions in sufficient quantities to induce localized genotoxic effects, but these changes revert on removal of the appliances.
固定正畸矫治器释放金属离子是人们关注的一个问题。本研究旨在评估佩戴固定矫治器患者口腔黏膜细胞的遗传毒性损伤，以及这些细胞中的镍和铬离子含量。
20 名正在接受正畸治疗的患者组成实验组，20 名未接受治疗的患者组成对照组。在 2 个时间点采集口腔黏膜涂片：拆除固定矫治器时和拆除后 30 天。用巴氏染色法对涂片进行染色，在光学显微镜下观察以评估微核的存在。采用电感耦合等离子体质谱法（ICP-MS）定量检测金属离子的存在。采用曼-惠特尼 U 检验和斯皮尔曼等级相关检验对数据进行分析。
拆除固定矫治器时，实验组的平均微核频率明显高于对照组；拆除后 30 天，差异较小，无统计学意义。实验组的镍和铬离子含量均明显低于对照组。微核频率与金属离子含量之间无相关性。
正畸矫治器的镍铬合金释放出足够数量的金属离子，会引起局部遗传毒性效应，但在拆除矫治器后这些变化会恢复正常。
