Sepideh Arab; Mina Hormozdiari Cham; Marzieh Morsaghian; Maryam Ghamari; Omid Mortezai
Abstract
Background: Stainless steel and Nickel Chromium alloys show special mechanical features, which has made them the most common materials for fabrication of orthodontic arch wires.
Objectives: The aim of this study was to evaluate the effect of length of immersion and type of arch wire on release of nickel ...
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Background: Stainless steel and Nickel Chromium alloys show special mechanical features, which has made them the most common materials for fabrication of orthodontic arch wires.
Objectives: The aim of this study was to evaluate the effect of length of immersion and type of arch wire on release of nickel and chromium ions from fixed orthodontic appliances.
Materials and Methods: 15 simulated half-arch maxillary fixed orthodontic appliances were divided into 3 groups according to the types of arch wires. Each sample was individually immersed in 50 ml of distilled water and incubated at 37ºC for 28 days. Afterwards, solutions were sent to laboratory for investigation of the released ions and the samples were incubated for another 28 days in new distilled water. After each 28-day time span, the concentrations of nickel and chromium were measured using an atomic absorption spectrophotometer. T-test was used for statistical analysis and P < 0.05 were considered statistically significant.
Results: Stainless steel arch wires released the greatest amount of nickel and chromium ions at both 28 days periods. The lowest amount of nickel and chromium in both time spans was released from NiTi and HANT arch wires, respectively Nickel ion release decreased overtime while the chromium release increased.
Conclusions: The amounts of released nickel and chromium ions from fixed orthodontic appliances from all three types of evaluated arch wires were below the daily dietary intake of these ions and do not bring about biological concerns.
Fariborz Amini; Maral Khazali; Farhang Mahmodei; Siamak Hematpour
Abstract
Objective: The aim of this study was to determine salivary concentrations of Nickel , Chromium and Cobalt ions in patients with fixed orthodontic appliances. Materials and Methods: This study was performed on salivary samples of 60 subjects including 30 subjects (20 females and 10 males) who were ...
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Objective: The aim of this study was to determine salivary concentrations of Nickel , Chromium and Cobalt ions in patients with fixed orthodontic appliances. Materials and Methods: This study was performed on salivary samples of 60 subjects including 30 subjects (20 females and 10 males) who were under orthodontic treatment with fixed orthodontic appliance for average of 1.5 to 2 years as study group and 30 individuals(20 females and 10 males) without any appliance therapy as control group. The chemical analyses of saliva was done with an electrothermal atomic absorption spectrophotometry to detect the metal ion content of the saliva. The Mann-Whitney u-test was used to analyze significance of the differences between two groups. Results: Examining the content of Nickel in the saliva of orthodontic patients and controls, the Nickel content of saliva in study group was significantly higher than the controls (p < 0.01). The mean salivary Chromium content was 13.60 ± 7.30 ng ⁄ ml, and 1.40 ± 4.80 ng/ml in subjects with and without orthodontic appliances respectively. Statistically significant differences were found between the groups (P < 0.002).Conclusion: fixed orthodontic appliances release measurable amount of Nickel and Cobalt when placed in the mouth however; this increase doesn’t reach toxic levels in saliva.
