Nickel In Saliva Research Articles

Effect of radiofrequency electromagnetic fields (RF-EMFS) from mobile phones on nickel release from orthodontic brackets: An in vitro study

The worldwide dramatic increase in the use of cell phones has generated great concerns about their potential adverse health effects. The aim of the present study was to evaluate the effects of radiofrequency electromagnetic fields (RF-EMFs) emitted from mobile phones on the level of nickel release from orthodontic brackets. Twenty stainless steel brackets were divided randomly into experimental and control groups (n=10). Brackets were immersed in artificial saliva at 37°C for 6 months. Experimental group were exposed to GSM 900MHz RF-EMFs emitted from a mobile phone stimulator for 4hours. The specific absorption rate (SAR) was 2.287W/kg. The concentration of nickel in the artificial saliva in both groups was evaluated by using the cold-vapour atomic absorption spectrometry. The Mann-Whitney test was used to assess significant differences in nickel release between the exposed and non-exposed groups. The mean nickel levels in the exposed and non-exposed groups were 11.95 and 2.89μg/l, respectively. This difference between the concentrations of nickel in the artificial saliva of these groups was statistically significant (P=0.001). Exposure to RF-EMFs emitted from mobile phones can lead to human exposure to higher levels of nickel in saliva in patients with orthodontic appliances. As nickel exposure can lead to allergic reaction in humans and considering this point that about 10-20% of the population can be hypersensitive to nickel, further studies are needed to evaluate the effects of radiofrequency electromagnetic fields (RF-EMFs) emitted from common devices such as mobile phones or Wi-Fi routers on the level of nickel release from orthodontic brackets.

An Accurate Methodology to detect Leaching of Nickel and Chromium Ions in the Initial Phase of Orthodontic Treatment: An in vivo Study.

The aim of this study was to evaluate the release of nickel and chromium ions in human saliva during fixed orthodontic therapy. Ten patients with Angle's Class-I malocclusion with bimaxillary protrusion without any metal restorations or crowns and with all the permanent teeth were selected. Five male patients and five female patients in the age group range of 14 to 23 years were scheduled for orthodontic treatment with first premolar extraction. Saliva samples were collected in three stages: sample 1, before orthodontic treatment; sample 2, after 10 days of bonding sample; and sample 3, after 1 month of bonding. The samples were analyzed for the following metals nickel and chromium using inductively coupled plasma optical emission spectrometry (ICP-OES). The levels of nickel and chromium were statistically significant, while nickel showed a gradual increase in the first 10 days and a decline thereafter. Chromium showed a gradual increase and was statistically significant on the 30th day. There was greatest release of ions during the first 10 days and a gradual decline thereafter. Control group had traces of nickel and chromium. While comparing levels of nickel in saliva, there was a significant rise from baseline to 10th and 30th-day sample, which was statistically significant. While comparing 10th day to that of 30th day, there was no statistical significance. The levels of chromium ion in the saliva were more in 30th day, and when comparing 10th-day sample with 30th day, there was statistical significance. Nickel and chromium levels were well within the permissible levels. However, some hypersensitive individuals may be allergic to this minimal permissible level.

Allergic Reactions and Nickel-Free Braces: A Review

Nickel is a constituent of many dental alloys. The aim of this review is to assess the most common allergic reactions reported in orthodontics related to nickel and the use of nickel free braces. A computerized literature search was conducted in PubMed for articles published on allergy in relation to orthodontics and nickel free braces. The MeSH term used was allergy, nickel free braces and orthodontics. Level of nickel in saliva and serum increases significantly after the insertion of fixed orthodontic appliances. Some nickel compounds, which are mildly cytotoxic, have been implicated as carcinogens by inhalation in industrial settings, but these compounds are not present in dental related operations. Studies have implicated allergy in the etiology of hypodontia. It has also been considered as a high risk factor for development of extensive root resorption during the course of orthodontic treatment. This review discusses the relationship and implications of allergy in orthodontics. Nickel-free braces (Ni content - 2% max.) seem to represent a viable alternative for orthodontic patients who are allergic to nickel. However, further in vivo studies, considering the immunology characteristics of patients, are needed to determine the clinical implications of the findings of this study.

Effect of mobile phone use on metal ion release from fixed orthodontic appliances

The aim of this study was to evaluate the effect of exposure to radiofrequency electromagnetic fields emitted by mobile phones on the level of nickel in saliva. Fifty healthy patients with fixed orthodontic appliances were asked not to use their cell phones for a week, and their saliva samples were taken at the end of the week (control group). The patients recorded their time of mobile phone usage during the next week and returned for a second saliva collection (experimental group). Samples at both times were taken between 8:00 and 10:00 pm, and the nickel levels were measured. Two-tailed paired-samples t test, linear regression, independent t test, and 1-way analysis of variance were used for data analysis. The 2-tailed paired-samples t test showed significant differences between the levels of nickel in the control and experimental groups (t [49]= 9.967; P<0.001). The linear regression test showed a significant relationship between mobile phone usage time and the nickel release (F [1, 48]= 60.263; P<0.001; R(2)= 0.577). Mobile phone usage has a time-dependent influence on the concentration of nickel in the saliva of patients with orthodontic appliances.

Níquel en cavidad oral de individuos con agrandamiento gingival inducido por tratamiento ortodóncico

Gingival overgrowth is an oral condition generated by the use of fixed orthodontic appliances. It was initially described as a product of the allergic response of the host to Nickel, and recent studies showed that this metal induces fibroblast proliferation. However, the degree of bioaccumulation of this metal in the oral cavity is unknown. The aim of this study was to quantify the concentrations of nickel in samples of saliva, dental plaque, and gingiva of individuals with fixed orthodontic appliances with and without gingival overgrowth. The sample size was established according to historical trends, evaluating 24 individuals with active orthodontic treatment, which were classified in two groups: 12 with gingival overgrowth (Group A) and 12 without gingival overgrowth (Group B). Samples of gingival, stimulated saliva and dental plaque were obtained from each participant. Once the sample were processed, nickel concentrations were measured in [mg/L] by atomic absorption spectrophotometry (Thermo Scientific. Atomic absorption spectrometer iCE 3000, UK). Statistical analysis was performed using SPSS v20. The levels of Nickel in samples of stimulated saliva, dental plaque and gingiva were compared between individuals in group A and group B. There were significantly higher levels of nickel in gingiva samples in group A (mean=0.61mg/L vs. 0.36mg/L, P=.001). However, no statistical difference was observed when comparing the concentrations of nickel in saliva between groups A and B (mean=0.502mg/L vs. 0.473mg/L, P=.178, respectively). The use of fixed orthodontic appliances leads to different levels of bioaccumulation of nickel in gingiva when comparing both groups. High concentrations of this metal are probably associated with the origin of gingival overgrowth. Further studies are required to establish causation.

Nickel in dental plaque and saliva in patients with and without orthodontic appliances

The aim of this study was to compare the content of nickel in the saliva and dental biofilm in young patients with and without orthodontic appliances. The possible influence of a dietary intake of nickel on recorded nickel levels was examined. Nickel content in unstimulated whole saliva and in dental plaque of 24 boys and girls (mean age 14.8 years) with intraoral fixed orthodontic appliances was compared with 24 adolescents without such an appliance. Sample collection was set up to exclude nickel contamination. Diet intake was recorded for the preceding 48 hours to account for the influence of recent nickel content in food. Saliva and plaque were analysed for nickel content using an electrothermal atomic absorption spectrometric (ETAAS) method. The acidified saliva samples were analysed as Millipore-filtered saliva with filter-retained fractions and plaque following dissolution in acids. No significant difference in nickel content of filtered saliva was found between the test and the control samples (P = 0.607); the median values of nickel content were 0.005 and 0.004 mug/g saliva, respectively. On the other hand, a significant difference was found for the filter-retained fraction (P = 0.008); median values for nickel were 25.3 and 14.9 mug/g, respectively. A significant difference in nickel content between test and control samples was also found in plaque collected at various tooth sites (P = 0.001; median values 1.03 and 0.45 mug/g, respectively). A stronger difference was found when comparing plaque collected from metal-covered tooth surfaces than from enamel surfaces of orthodontic patients. No association could be found between calculated dietary intake of nickel and recorded nickel in the test and control samples. It is concluded that nickel release occurs into the dental plaque and components of saliva of orthodontic patients, a situation that may reflect time dependence of its release from orthodontic appliances into the oral cavity and an aggregation of nickel at plaque sites.

Determination of Nickel in Saliva by Electrothermal Atomic Absorption Spectrometry Using Various Chemical Modifiers with Zeeman-effect Background Correction

The profile of nickel signal using electrothermal atomic absorption spectrometry with deuterium and Zeeman-effect background correction is presented. The Zeeman effect system of background correction offered definitive advantages and therefore was used for the determination of nickel in saliva in the presence of various isomorphous metals. The highest nickel absorbance values corresponded at 200, 300, 300, 300, 600, and 200 ng of Tb, Mg, Sm, Lu, Tm, and Pd, respectively. On the other hand, the addition of Eu, Er, and Ho decreased the nickel signal. The presence on each modifier alone does not eliminate the matrix interference. However, the use of 200 ng of Pd in conjuction with 300 ng of Lu has a higher sensitivity, offers an advantage against interference from the background of saliva matrix and produces good recoveries (98 to 102% from unspiked and spiked saliva samples). The limit of detection was 0.11 micrograms/L for a characteristic mass of 16.6 pg of nickel using Pd-Lu as modifier. The within-batch precision varied between 0.8 and 1.5% relative standard deviations. The analysis of thirty samples of whole saliva gave an average of 0.81 +/- 0.30 of micrograms/L of Ni (range from 0.5 to 2.0 micrograms/L of Ni). The agreement between the observed and certified values obtained from a Seronorm Blood Serum Standard Reference Material was good.