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[Color changes induced by fluoride on nickel-titanium orthodontic wires]
Chang-Bai Ma1, Xin-Qiang Liu, Jin-Hua Li
1Dept. of Stomatology, The Affiliated Hospital of Hangzhou Normal University, Hangzhou 310015, China.
Summary
Fluoride exposure causes noticeable color changes in nickel-titanium (Ni-Ti) orthodontic wires. Different Ni-Ti wire brands exhibit varying degrees of color alteration under the same fluoride conditions.
Area of Science:
- Materials Science
- Biomaterials Engineering
- Orthodontics
Background:
- Nickel-titanium (Ni-Ti) alloys are widely used in orthodontics due to their superelastic properties.
- The aesthetic appearance of orthodontic appliances is a growing concern for patients.
- Fluoride, commonly found in oral hygiene products and water, is a potential environmental factor affecting biomaterials.
Purpose of the Study:
- To investigate the effect of fluoride on the color stability of different brands of Ni-Ti orthodontic wires.
- To quantify the relationship between fluoride concentration and the extent of color change.
- To compare the color changes among various Ni-Ti wire types.
Main Methods:
- Four types of Ni-Ti orthodontic wires (IMD, SL, TP, YY) were immersed in artificial saliva containing varying concentrations of sodium fluoride (0.05%, 0.10%, 0.15%) for 28 days.
- A cyclic immersion protocol was employed, simulating daily exposure and rinsing.
- Color changes and micro-morphological alterations were systematically observed.
Main Results:
- A dose-dependent increase in color change was observed with rising fluoride concentrations (P < 0.05).
- Ni-Ti wires of brands IMD and YY showed significantly greater color changes compared to SL and TP at equivalent fluoride levels (P < 0.01).
- No significant color difference was found between IMD and YY, nor between SL and TP.
Conclusions:
- Fluoride ions demonstrably alter the surface color of Ni-Ti orthodontic wires.
- The susceptibility to fluoride-induced color changes varies among different Ni-Ti wire manufacturers.
- These findings have implications for the long-term aesthetics and material integrity of orthodontic appliances in fluoride-rich environments.
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