Statement of problem

The corrosive effects of oral fluoride products on titanium have been reported, and chronic fluorosis, which causes hyperfluoemia, is one of the world's health problems. Nevertheless, the relationship between high serum fluoride and corrosion on the titanium surface, which might have adverse effects on titanium implant osseointegration, has not been elucidated.

Purpose

The purpose of this in vitro study was to investigate the corrosion behavior of pure titanium exposed to high serum fluoride with different pH values based on surface analysis.

Material and methods

Pure titanium specimens, exposed to different electrolytes with 0.04 and 0.4 ppm NaF at pH 7.3 and 5.0 values, were examined for surface microstructure by using scanning electron microscopy (SEM) and for surface element composition with X-ray photoelectron spectroscopy (XPS). The corrosion behavior and metal ion release of specimens immersed in the Hanks’ balanced salt solution (HBSS) containing 0.04 and 0.4 ppm serum fluoride concentrations (NaF) at 7.3 and 5.0 pH values were measured by electrochemical impedance spectroscopy (EIS) and inductively coupled plasma atomic emission spectrometry (ICP-AES).

Results

Pitting holes were observed on pure titanium surfaces exposed to high serum fluoride. The surfaces became rougher with the increase of serum fluoride concentration, especially under acidic conditions. XPS analysis revealed a reduction of dominant titanium dioxide (TiO₂) on the pure titanium surface under serum fluoride exposure, corresponding to an increase in the relative level of F. EIS data showed an active corrosion behavior of pure titanium exposed to high serum fluoride and gradually decreased corrosion resistance with increasing concentration of serum fluoride, which was more severe under acidic conditions. The release of titanium ions was also induced by high serum fluoride and acidic conditions.

Conclusions

High serum fluoride had a negative influence on the corrosion behavior of pure titanium. The titanium oxide film barrier could be broken down in the fluoride ions condition, and the corrosion resistance of pure titanium decreased with the increasing concentration of serum fluoride. The increased corrosion susceptibility of pure titanium accelerated the release of titanium ions after exposure to high serum fluoride; this was more pronounced in an acidic environment.

中文翻译：

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纯钛在氟化物暴露下的表面分析和腐蚀行为。

问题陈述

据报道，口服氟化物产品对钛具有腐蚀作用，导致高血流的慢性氟中毒是世界卫生问题之一。然而，尚未阐明高血清氟化物与钛表面腐蚀之间的关系，这可能会对钛植入物的骨整合产生不利影响。

目的

这项体外研究的目的是基于表面分析，研究纯钛在不同pH值的高血清氟暴露下的腐蚀行为。

材料与方法

通过使用扫描电子显微镜（SEM）检查纯钛样品，使其在pH 7.3和5.0值下暴露于0.04和0.4 ppm NaF的不同电解质中，并通过X射线光电子能谱（XPS）检查表面微观结构和表面元素组成。通过电化学阻抗谱（EIS）和感应耦合等离子体测量了浸入在7.3和5.0 pH值下含0.04和0.4 ppm血清氟化物浓度（NaF）的汉克斯平衡盐溶液（HBSS）中的样品的腐蚀行为和金属离子释放原子发射光谱法（ICP-AES）。

结果

在暴露于高血清氟化物的纯钛表面上观察到点蚀孔。随着血清氟化物浓度的增加，表面变得更粗糙，尤其是在酸性条件下。XPS分析显示，在暴露于血清氟化物的情况下，纯钛表面上的主要二氧化钛（TiO ₂）减少，对应于F的相对含量的增加。EIS数据显示，暴露于高血清氟化物和温度下的纯钛的活性腐蚀行为。随着血清氟化物浓度的增加，耐腐蚀性逐渐降低，在酸性条件下更为严重。高血清氟化物和酸性条件也诱导了钛离子的释放。

结论

高血清氟化物对纯钛的腐蚀行为有负面影响。钛氧化物膜阻挡层在氟离子条件下会被破坏，并且纯钛的耐蚀性随着血清氟化物浓度的增加而降低。纯钛在较高的血清氟化物暴露后增加的腐蚀敏感性促进了钛离子的释放。这在酸性环境中更为明显。