Nickel hypersensitivity and orthodontic treatment: a systematic review and meta‐analysis

Abstract

SummaryNickel-containing alloys are widely used in orthodontic appliances, even though nickel is by far the most common contact allergen. However, the scientific evidence concerning allergic reactions to nickel in orthodontic patients has not been evaluated systematically. The objective of this study was to investigate whether the prevalence of nickel hypersensitivity is affected by orthodontic treatment. Unrestricted electronic and manual searches were performed until July 2013 for human clinical studies assessing orthodontic treatment and nickel hypersensitivity. Methodological limitations were evaluated with the Downs and Black tool. Crude and adjusted odds ratios (ORs) with their 95% confidence intervals (CIs) were calculated from random-effects meta-analyses, followed by subgroup and sensitivity analyses. Thirty studies were included in the review, and 24 datasets with 10 184 patients in the meta-analyses. Orthodontic treatment had no significant effect on nickel hypersensitivity (n = 11; crude OR 0.99; 95%CI: 0.78-1.25; p = 0.914). However, when confounding from factors such as sex and piercings was taken into account, orthodontic treatment was associated with a lower risk of hypersensitivity (n = 1; adjusted OR 0.60; 95%CI: 0.40-0.80; p < 0.001). This was even more pronounced when orthodontic treatment was performed prior to piercing (n = 7; crude OR 0.35; 95%CI: 0.24-0.50; p < 0.001). Orthodontic treatment seems to have a protective role against nickel hypersensitivity, especially when it precedes piercings.Key words: contact dermatitis; meta-analysis; nickel allergy; nickel hypersensitivity; orthodontics; piercing.Nickel allergy is by far the most common contact allergy in the industrial world, with a prevalence of up to 30%, depending on age, sex, and ethnicity (1, 2). Possible sources for nickel sensitization include jewellery, clothing fasteners, mobile phones, and, in particular, (ear) piercings. The last of these contributes to female patients being affected twice as often as men (3). Because of Accepted for publication 24 February 2015the increasing rate of nickel sensitization, the Danish Ministry of Environment mandated in 1992 that release from nickel-containing products in prolonged contact with the skin should be <0.5 μg/cm 2 , which subsequently decreased the prevalence of nickel allergy (4, 5). The EU followed its example with similar legislation in 1994 (6), which led to other reports of reduced nickel sensitization (25.8% as compared with 36.7%) (7). In contrast, the rate of nickel hypersensitivity has steadily increased in North America, where such regulatory mechanisms against nickel are lacking (1).Nickel-containing alloys exist in a wide variety of appliances and auxiliary devices used in orthodontics, with a content of up to 55% by weight. Likewise, the in vivo release of nickel ions varies greatly, from 0. to 105.7 μg/l, according to the alloy type, body fluid, temperature, mechanical stress, or pH (8, 9). In general, orthodontic materials are considered to be highly biocompatible ...

Smell and taste in titanium and nickel allergic sensitization in orthodontic patients

“…A recent meta-analysis reports an average prevalence of nickel hypersensitivity of 19% in orthodontic patients, 5 while our study found a somewhat lower prevalence. On the other hand, a low incidence of allergic reactions during orthodontic treatment is reported, ranging between 0.03% and 0.3%.…”

Nickel ion concentrations in the saliva of patients treated with self-ligating fixed appliances: a prospective cohort study

“…Even though Ni allergy is frequently observed during skin contact, allergic reactions in the oral cavity are rare [7,43]. In addition, there is evidence of a reduced prevalence of Ni hypersensitivity in patients having received orthodontic treatment before ear piercing [15,19]. Interestingly, new insights in pathomechanism of Ni hypersensitivity have revealed that a specific innate immune receptor (Toll-like receptor 4) is implicated in this event [42].…”

“…However, Ni is the main sensitizer for contact hypersensitivity and, therefore, often blamed for adverse reactions during orthodontic therapy. On the other side, a current meta-analysis indicated that orthodontic treatment may even reduce the incidence of Ni hypersensitivity, when the treatment preceded Ni sensitization through ear piercings [19]. Cases of Ni-induced allergic reaction during orthodontic therapy are rare and often related to extraoral appliances, as dermal Ni contact seems to be able to induce hypersensitivity more easily than the contact with oral mucosa.…”

The use of patch testing for the diagnosis of contact dermatitis: an Albanian experience

“…The higher prevalence among women is explained with the often and closed contact with objects containing nickel and/or cobalt, especially with jewelries and/or piercing which women start to use since early in life (36). The wide spread of nickel sulphate in our everyday life (in sunglasses frame, door handles, spoons and forks in the kitchen, medical instruments, dental materials, metal chair and as well as ingredient in a lot of food products) explains the high prevalence of positive patch tests to this substance compared to other allergens less common in everyday life (37,38). Besides industrial materials (cement, mortar, plaster, bricks), potassium dichromate is also common in everyday life and can be found in leather clothing, shoes, colored gloves, matches and tattoos (24,34,38).…”