Corrosion of dental nickel–aluminum bronze with a minor gold content‐mechanism and biological impact

Abstract

The nickel-aluminum bronze showed high corrosion rate caused by an inability to create a protective surface layer. High levels of toxic elements were found after static immersion testing, and the corrosion products had a distinct adverse effect on the biological activity.

Chemical recycling of PET flakes into yarn

“…They found pits with depths and widths in the range 0.5–1 μm. In agreement, Ardlin et al35 reported high corrosion rate for this copper alloy due to its inability to create a protective surface layer. Additionally, they found high levels of toxic ions after static immersion testing, with adverse effect on the biological activity in the surroundings.…”

“…To assess the metal ions release square shape sheets of the casting copper alloy of about 49 cm 2 of geometrical area were immersed for 24 h, at 37°C in 200 mL of acid synthetic saliva (SS) pH = 4.77 to assay the aggressive condition of low pH related to fermentable dietary sugars, metabolic products of dental plaque,35 and so on. After this 24 h period of static immersion, the metal ion concentrations in the SS medium was measured (AC24h) by atomic absorption spectrophotometry using a VARIAN Spectrophotometer model SpectrAA55 (serial number EL99043438).…”

“…Despite expressed doubts as to their suitability,32 copper‐based alloys have been used as dental casting alloys for fixed prosthesis in the US, Japan, South America, and some countries of Eastern Europe for more than 25 years 33, 34. According to dental technicians and dental suppliers, their popularity is due to their good mechanical strength, high elastic modulus, low density, its bright yellow colour with strong resemblance gold and its low‐cost relative to noble metal alloys 35–37…”

“…Clinical studies have shown that corrosion of crowns and posts of such alloys causes staining and inflammatory processes in the surrounding gum tissue and blue–green pigment in the roots of teeth 36, 37. Thus, the widespread use of copper‐based alloys in several countries is a cause of great concern due to the undesirable effects found on surrounding cells by metals ions released from these alloys (Cu, Ni, Zn, Al ions) 33, 35, 36, 38…”

Release of soluble metal ions from copper based dental alloys measured by ICPMS

“…Copper-based alloys have been used as an alternative to gold based alloys for dental crown and bridge applications. Their popularity is mainly due to their bright gold-like appearance and a lower cost when compared to alloys made from noble metals (Ardlin et al, 2009). Release of metal ions (Cu and Ni) and microparticles which may induce inflammation of the adjacent periodontal tissues and the oral mucosa has been documented in both in vitro and in vivo studies involving metallic dental devices (Geurtsen, 2002).…”