Laboratory for the Chemistry of Construction Materials (LC(2)), Department of Civil and Environmental Engineering, University of California, Los Angeles, CA, USA.
School of Dentistry, University of California, Los Angeles, CA, USA.
Dent Mater. 2020 Mar;36(3):431-441. doi: 10.1016/j.dental.2020.01.008. Epub 2020 Jan 25.
The Ti-6Al-4V (TAV) alloy is commercially used as a dental implant material. This work seeks to elucidates the origins of degradation of Ti-6Al-4V (TAV) implant alloys that result in peri-implant bone loss. Methods: In this work, a combination of microstructure, surface, and solution analyses was utilized to study the corrosion mechanism of the TAV alloy in oral environments. The corrosion of TAV alloys in the F-enriched environment of a crevice was evaluated through nanoscale surface analysis. And, the findings were further rationalized via electrochemical means. RESULTS: Our results suggest the bone loss was caused by crevice corrosion and the consequential release of by-products, and the crevice corrosion was potentially induced by the buildup of corrosive species such as fluorides, which are common additives in dental products. In turn, the corrosion properties of the TAV alloy were evaluated in fluoride enriched environments. Nanoscale analysis of corroded surfaces, carried out using vertical scanning interferometry (VSI) showed that the corrosion susceptibility of the constituent phases dictates the corrosion product species. In specific, the aluminum-rich α phase preferentially dissolves under potential-free conditions and promotes the formation of insoluble Al-Ti oxides. Notably, under conditions of applied potential, oxidative dissolution of the vanadium-rich β phase is favored, and the vanadium release is promoted. SIGNIFICANCE: These findings elucidate the origins of degradation of TAV-implants that result in the release of corrosion by-products into the local biological environment. More important, they offer guidelines for materials design and improvement to prevent this nature of degradation of dental implants.
钛-6 铝-4 钒（TAV）合金被广泛应用于牙科植入物材料。本研究旨在阐明导致种植体周围骨丧失的 TAV 植入物合金降解的起源。
本研究采用微观结构、表面和溶液分析相结合的方法，研究了 TAV 合金在口腔环境中的腐蚀机制。通过纳米尺度表面分析评估了 TAV 合金在口腔环境中富 F 环境裂隙中的腐蚀情况，并通过电化学手段进一步合理化研究结果。
研究结果表明，骨丢失是由缝隙腐蚀和副产物的释放引起的，而缝隙腐蚀可能是由氟化物等腐蚀性物质的积累引起的，氟化物是牙科产品中的常见添加剂。因此，在富氟环境中评估了 TAV 合金的腐蚀性能。使用垂直扫描干涉测量法（VSI）对腐蚀表面进行纳米尺度分析表明，组成相的腐蚀敏感性决定了腐蚀产物的种类。具体来说，富铝的α相在无电位条件下优先溶解，并促进不溶性 Al-Ti 氧化物的形成。值得注意的是，在施加电位的条件下，富钒的β相更倾向于发生氧化溶解，从而促进了钒的释放。
这些发现阐明了导致 TAV 植入物降解并将腐蚀副产物释放到局部生物环境中的原因。更重要的是，它们为材料设计和改进提供了指导，以防止这种牙科植入物的降解。
