Metallic ion content and damage to the DNA in oral mucosa cells of children with fixed orthodontic appliances

Abstract

Although the metal devices used in orthodontic treatments are manufactured highly resistance to corrosion, they may still suffer some localized corrosion resulting from the oral cavity conditions. The corrosion causes the release of metals from the alloys used for their manufacture. In this report, we evaluated the in vivo metal ions release of three alloys (stainless steel, titanium and nickel-free) usually used in the orthodontics treatments and its genotoxicity. We applied to 15 patients, between 12 and 16 years, 4 tubes and 20 brackets. Samples from oral mucosa were taken before the treatment and 30 days later. The concentration of the titanium, chromium, manganese, cobalt, nickel, molybdenum and iron were detected using inductively coupled plasma mass spectrometry (ICP-MS). The genotoxicity was measured with a comet assay (Olive moment). The oral mucosa cells in contact with the stainless steel alloy displayed the greatest titanium and manganese concentrations and those in contact with the nickel-free alloy presented the greatest concentration of chromium and iron. Both alloys, stainless steel and nickel-free, induced a higher DNA damage in the oral mucosa cells than the titanium alloy, in which the Olive moment was similar to controls. Based on the results of our study, we can conclude that titanium brackets and tubes are the most biocompatible of the three alloys.

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

“…Case reports of allergic reactions during orthodontic therapy support this suspect [11,26]. Moreover, in-vitro evidence indicates that Ni can cause cytotoxic, immunogenic, mutagenic or carcinogenic processes in dependence on the chemical form, concentration, duration and route of exposure [9,14,18,30,47]. The most common adverse effect in orthodontics is the induction of allergic reactions and Ni is by far the most common contact allergen [45].…”

Trace metal ions release from fixed orthodontic appliances and DNA damage in oral mucosa cells by in vivo studies: A literature review

“…21 There was no control group. The authors evaluated metal ions released from 3 alloys (stainless steel, n = 5; titanium, n = 5; nickel-free, n = 5).…”

“…18 In the Fernandez-Minano study, after 30 days of contact with fixed orthodontic appliances, the cheek mucosa cells of the patients increased their concentrations of titanium and manganese. 21 For the patients wearing titanium orthodontic appliances, the manganese content increased and wearers of nickel-free apparatus showed increased concentrations of chromium and iron. Some researchers have failed to find differences in chromium ion concentration.…”

“…Additionally, in 3 of the studies, no control group was used. [21][22][23] Finally, ion release from fixed orthodontic devices in vivo is affected by various factors, such as saliva composition, pH, dietary habits, and microflora.…”

“…Faccioni et al presented 3 forms damaging the DNA structure (comets, apoptosis and viability), whereas other authors presented one in different units. 17,[19][20][21][22][23] The results presented by Angelieri et al and Heravi et al showed that the micronucleus frequencies were not significantly different before, during and after orthodontic treatment, and are in contrast with those of Natarajan et al, who found a significantly higher MN count in the test group at the day of debonding as compared to the control group without appliances. 20,22,23 Hafez et al 19 found that the cytotoxicity and genotoxicity of orthodontic appliances remained in the mouth for 6 months.…”