Department of Orthodontics, Oral and Dental Research Division, National Research Center, Giza, Egypt.
Am J Orthod Dentofacial Orthop. 2011 Sep;140(3):298-308. doi: 10.1016/j.ajodo.2010.05.025.
Treatment with fixed orthodontic appliances in the corrosive environment of the oral cavity warrants in-vivo investigations of biocompatibility.
Eighteen control and 28 treated subjects were evaluated longitudinally. Four combinations of brackets and archwires were tested. Buccal mucosa cell samples were collected before treatment, and 3 and 6 months after appliance placement. The cells were processed for cytotoxicity, genotoxicity, and nickel and chromium contents.
In the treatment group, buccal mucosa cell viability values were 8.1% at pretreatment, and 6.4% and 4.5% at 3 and 6 months, respectively. The composite score, a calculated DNA damage value, decreased from 125.6 to 98.8 at 6 months. Nickel cellular content increased from 0.52 to 0.68 and 0.78 ng per milliliter, and chromium increased from 0.31 to 0.41 and 0.78 ng per milliliter at 3 and 6 months, respectively. Compared with the control group, the treated subjects showed significant differences for DNA damage and chromium content at 3 months only.
Fixed orthodontic appliances decreased cellular viability, induced DNA damage, and increased the nickel and chromium contents of the buccal mucosa cells. Compared to the control group, these changes were not evident at 6 months, possibly indicating tolerance for or repair of the cells and the DNA.
在口腔腐蚀性环境中使用固定正畸矫治器需要进行体内生物相容性研究。
18 名对照组和 28 名治疗组受试者进行纵向评估。测试了四种托槽和弓丝的组合。在治疗前、治疗后 3 个月和 6 个月采集颊黏膜细胞样本。对细胞进行细胞毒性、遗传毒性、镍和铬含量检测。
在治疗组中，治疗前颊黏膜细胞活力值为 8.1%，治疗后 3 个月和 6 个月分别为 6.4%和 4.5%。复合评分（一种计算 DNA 损伤值）从 6 个月时的 125.6 降至 98.8。镍细胞内含量分别从 0.52 增至 0.68 和 0.78ng/ml，铬从 0.31 增至 0.41 和 0.78ng/ml。与对照组相比，治疗组在 3 个月时仅在 DNA 损伤和铬含量方面存在显著差异。
固定正畸矫治器降低了细胞活力，诱导了 DNA 损伤，并增加了颊黏膜细胞的镍和铬含量。与对照组相比，这些变化在 6 个月时并不明显，可能表明细胞和 DNA 具有耐受性或修复能力。
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