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Changes on NiTi orthodontic wired due to acidic fluoride solution.
Yong Hoon Kwon1, Young-Doo Cheon, Hyo-Joung Seol
1Department of Dental Materials, College of Dentistry and Medical Research Institute, Pusan National University, Pusan 602-739, Korea. y0k0916@pusan.ac.kr
Dental Materials Journal
|February 4, 2005
Summary
Acidic fluoride solutions affect nickel-titanium (NiTi) arch wire properties. Increased fluoride concentration and immersion time, along with decreased pH, significantly impact tensile strength and element release from NiTi arch wires.
Area of Science:
- Materials Science
- Biomaterials Engineering
- Dental Materials
Background:
- Nickel-titanium (NiTi) arch wires are widely used in orthodontics due to their unique properties.
- Exposure to acidic environments, such as those found in the oral cavity, can potentially alter the mechanical and chemical integrity of NiTi arch wires.
- Understanding the effects of acidic fluoride solutions is crucial for predicting long-term performance and biocompatibility of orthodontic appliances.
Purpose of the Study:
- To investigate the impact of acidic fluoride solutions on the crystal structure, tensile strength, fracture morphology, and elemental release of NiTi arch wires.
- To determine the influence of sodium fluoride (NaF) concentration, pH, and immersion duration on these properties.
Main Methods:
- NiTi arch wires were immersed in four different acidic fluoride solutions for 1 or 3 days.
- Crystal structure was analyzed using X-ray diffraction.
- Tensile strength was measured using mechanical testing.
- Fracture surfaces were examined using scanning electron microscopy.
- Element release into the test solutions was quantified using appropriate analytical techniques.
Main Results:
- No new crystal structures were formed after 3-day immersion in a 0.2%/pH 4 solution.
- Tensile strength varied among different NiTi wire brands (3M increased, G&H and Ormco decreased) and was significantly affected by immersion time.
- Fractured wires exhibited dimple patterns internally and ductile features externally.
- Element release increased with higher NaF concentration, longer immersion periods, and lower pH values.
- A 0.2%/pH 4 solution released significantly more elements than a 0.05%/pH 4 solution.
Conclusions:
- Acidic fluoride solutions significantly affect the tensile strength and elemental release of NiTi arch wires.
- NaF concentration, pH, and immersion duration are critical factors influencing these changes.
- The findings highlight the importance of considering the oral environment's chemical challenges for NiTi arch wire stability and performance.