Nickels and tines: the myth of nickel allergy in intracranial stents

BackgroundMost intracranial stents contain nickel alloy, and nickel allergy or hypersensitivity is common. Neurological injury following endovascular treatment with a nickel containing intracranial stent has been reported in patients with purported nickel allergy, but it is unclear whether these reactions represent true nickel hypersensitivity. We quantified nickel release from commonly used intracranial stents to investigate whether such stents should be avoided in patients with nickel allergy.MethodsWe examined nickel release from seven commonly used intracranial stents: Enterprise, LVIS Jr, Neuroform, Wingspan, Zilver, Pipeline Flex Embolization Device, and Surpass Evolve. We incubated each stent in human plasma-like media for 30 days. Dimethylglyoxime (DMG) spot testing was performed on each stent to detect released nickel at 0 and 30 days. Inductively coupled plasma–optical emission spectroscopy (ICP-OES) was then used to quantify the nickel concentration of the media at 30 days. Nickel currency and nickel standard for atomic absorption spectrometry were used as positive controls.ResultsDMG spot tests indicated nickel release only from nickel currency at 0 and 30 days of incubation. No nickel release was detected from any stent at 30 days using ICP-OES.ConclusionsNickel release from commonly used intracranial stents is negligible. These results suggest that previously reported hypersensitivity to these stents may be misattributed to nickel allergy, and that patients with nickel allergy may be safely treated with select nickel-containing stents.

Influence of pH Level and Type of Archwire on the Time Bound Release of Nickel Ions from Orthodontic Appliances - An In Vitro Study

BACKGROUND Orthodontic metallic appliances in the oral cavity are constantly in contact with biological fluids or tissues thereby releasing particulate masses. They can be common causes of contact allergies and should be considered as a critical issue in determining properties of biomaterials. Nickel ions in various forms and compounds have been known to cause carcinogenic, mutagenic, cytotoxic and allergenic reactions. Pattern of metal ions released from different stainless steel orthodontic appliances in vitro could provide valuable information to consider their application in clinical scenarios. The purpose of the present study was to evaluate metal ions released under different ph levels, immersion period time and using different archwire orthodontic appliances. METHODS Orthodontic appliances were constructed consisting of five brackets from central incisor to the second premolar, a buccal tube welded molar band and an archwire that were used as samples. Total of twelve appliances were constructed; using stainless steel, Ni - Ti, and Thermal Ni - Ti wires (N = 4 each). Half of these samples were immersed in artificial saliva at pH 3.5 and the other half were immersed in artificial saliva at pH 6.75. The samples were stored in an incubator at a temperature of 37 degrees Celsius. Saliva samples from these bottles were collected at the end of 1, 7, 14 and 28 days and subjected to spectrophotometric analysis for estimation of nickel content. RESULTS Nickel release was maximum during the first week of immersion from orthodontic appliances comprising of Ni - Ti wires compared to Stainless steel and thermal Ni - Ti. A gradual decline in the nickel release was observed in the subsequent weeks. Ion release was increased by 30 times in the acidic pH medium, as compared to neutral pH conditions. CONCLUSIONS There is a definite release of nickel ions from orthodontic appliances when exposed to oral environment; however, the amounts are much lower than the daily dietary intake and don’t pose risk of toxicity. Care should be taken in patients with nickel hypersensitivity and wires such as beta - titanium or epoxy coated wires can be substituted. As there is an increase in ion release under acidic conditions the patients need to maintain hygienic oral environment thereby limiting corrosion of appliances. KEY WORDS NitiAlloy, Archwires, pH, Hypersensitivity

Evaluation of Nickel Release in Blood and Periodontal Tissue with the Use of NiTi Wires, Bands and Brackets in Orthodontics – A Systematic Review

BACKGROUND It is of outmost importance to know the effects of nickel on a cellular level. The objective of this systematic review was to analyse the factors affecting nickel release, the amount of nickel being released in commercially available NiTi wires and to also analyse the blood / periodontal evaluation after orthodontic treatment in conventional and nickel free brackets. METHODS For this systematic review, relevant articles were searched in PubMed, MedLine, Cochrane, EMBASE and Google Scholar databases, along with a complimentary manual search of all orthodontic journals from January 1980 till the year 2019 December. The study included in vitro and in vivo studies. 14 articles were included in this systematic review. RESULTS 160 articles were obtained initially. 41 were obtained by a manual search. 186 articles were excluded based on the inclusion criteria and 14 articles were found to be eligible. CONCLUSION This systematic review shows that nickel solution at a minimal concentration could damage human gingival fibroblast. As the carcinogenic effect of nickel has been already confirmed, other alloys that do not contain the heavy metal nickel can be used or standardization of the amount of nickel leach out from the appliance should be considered. KEY WORDS NiTi, Nickel Release, Periodontal Tissue or Periodontium, Cytotoxicity, Orthodontics

Trimming and pH Effects on Nickel Ion Release from Stainless Trimming and pH Effects on Nickel Ion Release from Stainless Steel Crowns of Primary Teeth Steel Crowns of

Objective: Stainless steel crowns (SSCs) are preformed metal crowns used to restore severely decayed primary teeth. The aim of this study is to evaluate the effects of pH changes and SSC margin trimming on nickel release in artificial saliva solution. Methods: A total of 90 SSCs were divided into three groups and placed in 35 ml of artificial saliva of pH 6.8, 5, and 3.5. Another group consisting 30 SSCs with trimmed margins was placed in saliva of pH 6.8. All SSCs were incubated at 37°C. The concentration of released nickel was assessed on days 1, 7, 14, 21, and 28 by atomic absorption spectrophotometry. Results: The highest concentrations of nickel were released on the first day in all groups. Nickel release increased with decreasing pH, and the differences observed were statistically significant on days 1, 7, 14, and 28. SSC trimming caused a significant increase in nickel release on all days except day 21. Conclusion: The concentration of nickel increased in saliva of low pH. The highest levels of nickel were released with SSC margin trimming because of the loss of integrity of the margins.

Effect of contamination sources on the rate of zinc, copper and nickel release from various soil ecosystems

Background and objective Soil is a substantive component in biosphere habitually endangered to superfluity contaminants particularly potential toxic elements (PTEs). The source of soil contaminants is very critical in controlling both their release and expected hazards in the different soil ecosystems. This study aims to investigate the effect of low-quality irrigation water (LQW) on the extent of soil pollution through desorption of zinc (Zn), nickel (Ni) and copper (Cu) from different polluted soils, collected from LQW irrigated farms for more than 40–80 years at Giza and Kafr-Elsheikh Governorates, Egypt. Results Models incorporated modified Freundlich (MFE), Elovich, first order and parabolic diffusion (PDE) showed significant results in describing the kinetic data under Egyptian conditions. Results entailed that according to the coefficient of determination (R2) and standard error, all used models well described the desorption of Cu, Ni and Zn, the most prevalent contaminants in the trailed soil ecosystems; for example, the R2 values were higher than 0.96** for zinc desorption using MFE model. As far as the PTEs levels are considered, the highest contaminant desorption rates were recorded at Kafr-Elsheikh site, followed by Kombora, and the lowest ones were in Abo Rawash soil ecosystem. The succession of more than one model to describe the kinetic perspective confirmed that the different mechanisms take place in PTEs sorption, distribution and subsequently release from different soil ecosystems. Conclusions The numerical values indicated that the soil ecosystems contaminated with industrial effluents were higher than those irrigated with sewage effluents regardless of the type of land use. More attention should be paid to low-quality water application in agriculture irrigation and its environmental risks.