RESUMO
Objective: Orthodontic wires should have high resistance against corrosion in the oral environment. Since the effect of pH on corrosion has been well recognized, this study sought to assess and compare the electrochemical corrosion of orthodontic brackets and wires of different brands in acidic artificial saliva
Methods: This in vitro experimental study was conducted on 24 mandibular central incisor brackets of 4 manufacturers namely Dentaurum, American Orthodontics, Shinye and ORJ. The brackets were immersed in acidic artificial saliva along with stainless steel [SS] or NiTi 0.016 round wires for 28 days. All specimens were weighed before and after the experiment by a digital scale. After the experiment, the specimens were evaluated under a light stereomicroscope and specimens with corrosion were further assessed by scanning electron microscope [SEM] and energy-dispersive Xray spectroscopy [EDX]. Two-way ANOVA was used for statistical analysis
Results: The mean corrosion rate [CR] was -1.80, 0.11, 0.05 and -0.93 mpy for Dentaurum, American Orthodontics, Shinye and ORJ brackets, respectively in combination with NiTi wire; these values were 0.46, -0.71, 0.87 and -0.27 mpy, respectively in combination with SS wires; the differences in this regard were not statistically significant [p>0.05]. Micrographs showed high corrosion in ORJ brackets followed by Shinye brackets. EDX showed that the combination of ORJ bracket with SS wire had the highest iron [Fe] content and the highest CR
Conclusion: SS brackets manufactured by Shinye and ORJ companies in combination with SS wires showed higher CR in acidic artificial saliva compared to other bracket/wire combinations
RESUMO
Objective: Corrosion resistance is among the most important properties of metal alloys used in the oral cavity. Consumption of acidic foods reduces the salivary pH and intensifies the corrosion of brackets and orthodontic wires. This study aimed to compare electro galvanic corrosion of different orthodontic brackets and wires and determine the amount of ions released into acidic artificial saliva
Methods: In this in vitro experimental study, 24 mandibular incisor brackets of 4 different manufacturers [Dentaurum, American Orthodontics, Shinye and ORJ] with stainless steel [SS] or nickel-titanium [Ni-Ti] round wires 0.016 were immersed in acidic artificial saliva for 28 days and their potential difference with the reference electrode was recorded. The amount of released ions was measured in the solution using atomic absorption method. Data were analyzed using two-way ANOVA and repeated measures ANOVA
Results: The mean amount of ions released was not significantly different between groups [p>0.05]. The potential difference of Shinye brackets coupled to SS wire was significantly lower than that of other combinations and was negative throughout the study. The potential difference of Dentaurum bracket-NiTi wire, ORJ bracket-NiTi wire, Shinye bracket-SS wire and ORJ bracket-SS wire combinations at the end of experiment was negative as well
Conclusion: The galvanic corrosion of Shinye bracket coupled to SS wire in acidic artificial saliva was greater than that of other bracket-wire combinations. The specimens were not significantly different in terms of the released ions