Ouédraogo Youssouf, Sakira Abdoul Karim, Ouédraogo Moussa, Tapsoba Issa, Konsem Tarcissus, Beugré Jean Bertin
Health Sciences Training and Research Unit, Joseph KI-Zerbo University, Ouagadougou, Burkina Faso.
Training and Research Unit in Exact and Applied Sciences, Joseph KI-Zerbo University, Ouagadougou, Burkina Faso.
J Orthod Sci. 2024 Nov 25;13:49. doi: 10.4103/jos.jos_8_24. eCollection 2024.
The aim of this study was to make a laboratory assessment of pH influence on the kinetics of the release of nickel ions in artificial saliva.
In this study, 15 basic orthodontic appliances are immersed in 15 polyethylene tubes each containing 40 ml of artificial saliva. Tubes were divided into three sub-groups of 5 tubes depending on the pH: pH 5, pH 7 and pH 8. The release of nickel ions was measured using atomic absorption spectrometry in a sample of 5 ml of artificial saliva taken one hour, four hours and one hundred and sixty-eight hours after immersion in a water bath at 37°.
Significance threshold was set at 0.05. A Student T test and the 2-way Anova test (with a Bonferoni post-test) were used respectively to compare the means.
The neutral pH causes a low release of nickel ions. The release kinetics of nickel ions is minimal for neutral pH, it increases when pH varies. After one hour of immersion, the nickel released did not reach the spectrometer quantification threshold as for neutral and acid pH. The alkaline pH causes an average release of nickel ions from the beginning without kinetic variation. As time passes (T3), the acidic pH causes more nickel ions release through a succession of oxidation-reduction reactions. After 168 hours, the average mass of nickel released is 0.30 µg for pH 7, 1.35 µg for pH 8 and up to 2.85 µg for pH 5.
Quantities released did not reach nickel toxicity threshold in humans. Orthodontists must consider the potential risk of hypersensitivity due to nickel in fixed orthodontic appliances.
本研究旨在对pH值对人工唾液中镍离子释放动力学的影响进行实验室评估。
在本研究中，将15个基本正畸矫治器浸泡在15个聚乙烯管中，每个管中含有40毫升人工唾液。根据pH值，将管子分为三个亚组，每组5个管：pH 5、pH 7和pH 8。在37°水浴中浸泡1小时、4小时和168小时后，从5毫升人工唾液样本中使用原子吸收光谱法测量镍离子的释放量。
显著性阈值设定为0.05。分别使用学生t检验和双向方差分析（采用Bonferroni事后检验）来比较均值。
中性pH值导致镍离子释放量较低。镍离子的释放动力学在中性pH值下最小，当pH值变化时会增加。浸泡1小时后，对于中性和酸性pH值，释放的镍未达到光谱仪定量阈值。碱性pH值从一开始就导致镍离子平均释放，且无动力学变化。随着时间推移（T3），酸性pH值通过一系列氧化还原反应导致更多镍离子释放。168小时后，pH 7时镍的平均释放质量为0.30微克，pH 8时为1.35微克，pH 5时高达2.85微克。
释放量未达到人体镍中毒阈值。正畸医生必须考虑固定正畸矫治器中镍引起超敏反应的潜在风险。
