Oral Factors Affecting Titanium Elution and Corrosion: An In Vitro Study Using Simulated Body Fluid

Abstract

ObjectivesTi, which is biocompatible and resistant to corrosion, is widely used for dental implants, particularly in patients allergic to other materials. However, numerous studies have reported on Ti allergy and the in vitro corrosion of Ti. This study investigated the conditions that promote the elution of Ti ions from Ti implants.MethodsSpecimens of commercially pure Ti, pure nickel, a magnetic alloy, and a gold alloy were tested. Each specimen was immersed in a simulated body fluid (SBF) whose pH value was controlled (2.0, 3.0, 5.0, 7.4, and 9.0) using either hydrochloric or lactic acid. The parameters investigated were the following: duration of immersion, pH of the SBF, contact with a dissimilar metal, and mechanical stimulus. The amounts of Ti ions eluted were measured using a polarized Zeeman atomic absorption spectrophotometer.ResultsEluted Ti ions were detected after 24 h (pH of 2.0 and 3.0) and after 48 h (pH of 9.0). However, even after 4 weeks, eluted Ti ions were not detected in SBF solutions with pH values of 5.0 and 7.4. Ti elution was affected by immersion time, pH, acid type, mechanical stimulus, and contact with a dissimilar metal. Elution of Ti ions in a Candida albicans culture medium was observed after 72 h.SignificanceElution of Ti ions in the SBF was influenced by its pH and by crevice corrosion. The results of this study elucidate the conditions that lead to the elution of Ti ions in humans, which results in implant corrosion and Ti allergy.

Surface characterization of titanium implant healing abutments before and after placement

“…This biofilm can induce inflammation in adjacent tissues and disrupt osseointegration, resulting in peri‐implant mucositis or peri‐implantitis . In addition, metabolic byproducts of anaerobic bacteria such as S. Mutans , can locally lower the pH of the fluid surrounding the peri implant pocket or contacting surfaces of the peri implant mucosa . Although titanium is protected by its passive oxide layer, acidic metabolites like lactic acid can induce corrosion in titanium by depleting oxygen sources required for repassivation, hindering the ability of the material to reform the oxide layer .…”

Titanium Corrosion Mechanisms in the Oral Environment: A Retrieval Study

“…It has been shown in vitro that corrosion of Ti grade 2 was higher in saliva containing Escherichia coli lipopolysaccharide (LPS) and at low pH levels [3]. Suito et al [14] demonstrated in an immersion study of Ti in simulated body fluid of varying pH that the lower the pH and the longer the immersion time, the greater the amount of Ti ions released. The same behavior was observed in the presence of mechanical stimulus during immersion and when in contact with a dissimilar metal.…”

“…Five implants showing particular corrosion features were characterized using different microscopy techniques. Characterization of these surfaces can help to clarify the mechanisms and dynamics behind the elution of Ti in the body, which remains unclear up to this date [14]. …”

Scanning Electron Micrographic Investigation of Explanted (Used) Metallic Biomedical Implants for Corrosion and Other Mechanical Damage Responsible for Failure

“…Although there are many studies reporting corrosion and mechanical damage of metallic implants in vivo, including detailed Scanning Electron Micrography [9]- [12], the authors do not find any work, particularly corresponding to patients in Indian subcontinent, where metallurgical investigations are corroborated with the clinical findings on the same implants.…”