背景:分析在模拟体液环境中断裂根管成形器械的表面和镍离子释放特性的变化。
方法:共研究了54种新仪器。仪器组由五种不同的NiTi合金和一种不锈钢合金组成。为规范仪器断裂,在每个仪器上都会产生扭转类型的故障。将每个仪器组的骨折标本随机分为3个静态浸泡亚组,1h,7天,30天(n=3)。通过Kokubo和Takadama协议制备模拟体液(SBF)以模拟人血浆,用于在37ºC下进行非原位静态浸入。通过扫描电子显微镜和能量色散X射线光谱法检查表面。为了确定定量离子释放,使用电感耦合等离子体质谱法分析检索到的SBF。双向ANOVA和Tukey事后检验寻求镍离子值的统计学显著性(p<0.05)。
结果:浸泡1小时后,新形成的结构,主要表现出氧气信号,在NiTi表面上广泛且明显。相比之下,在该亚组中,在SS表面检测到较少的结构。浸泡7天,在NiTi组中揭示了新结构密度降低的趋势。NiTi组表面的氧信号明显增加,与SS的减少相反。钠的信号,氯,和钙被检测到,表明成组的盐沉淀。在30天的浸泡中,盐沉淀继续形成。在所有浸泡期,与SBF对照相比,所有仪器组中的Ni离子释放值呈现显著差异(p<0.001)。在浸泡时间段或仪器组没有观察到显著差异(p>0.05)。
结论:在本研究的局限性内,结论是断裂的SS和NiTi根管器械释放与体液接触的Ni离子。然而,在观察期间确定的Ni离子释放值低于为人体定义的临界毒性或过敏阈值。这是由于离子溶解周期从1小时到30天暴露于骨折器械的体液中达到稳定状态。
To analyse the changes in surface and nickel ion release characteristics of fractured root canal shaping instruments in a simulated body fluid environment.
A total of 54 new instruments were studied. The instrument groups consisted of five different NiTi alloys and a stainless-steel alloy. To standardize instrument fracture, a torsional type of failure was created on each instrument. The fractured specimens of each instrument group were randomly divided into three static immersion subgroups of 1 h, 7-day, and 30-day (n = 3). Simulated body fluid (SBF) was prepared to mimic human blood plasma by Kokubo&Takadama protocol for ex situ static immersions at 37ºC. The surfaces were examined via scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy. To determine the quantitative ion release, the retrieved SBFs were analyzed using inductively coupled plasma mass spectrometry. Two-way ANOVA and Tukey post hoc tests sought the statistical significance of the nickel ion values(p < 0.05).
In 1 h of immersion, the newly formed structures, exhibiting mostly oxygen signals, were widespread and evident on NiTi surfaces. In contrast, fewer structures were detected on the SS surface in that subgroup. In 7 days of immersion, a tendency for a decrease in the density of the new structures was revealed in NiTi groups. The oxygen signals on NiTi group surfaces significantly increased, contrary to their decrease in SS. Signals of sodium, chlorine, and calcium were detected, indicating salt precipitates in groups. In 30 days of immersion, salt precipitates continued to form. The Ni-ion release values in all instrument groups presented significant differences in comparison to the SBF control in all immersion periods(p < 0.001). No significant differences were observed in immersion time periods or instrument groups(p > 0.05).
Within the limitations of the presented study, it was concluded that the fractured SS and NiTi root canal instruments release Ni ions in contact with body fluid. However, the Ni ion release values determined during the observation periods are lower than the critical toxic or allergic thresholds defined for the human body. This was due to the ionic dissolution cycle reaching a stable state from 1-hour to 30-day exposure to the body fluid of fractured instruments.