Abstract
Objective: To test the hypothesis that a diamond-like carbon coating does not affect the frictional properties of orthodontic wires. Materials and Methods: Two types of wires (nickel-titanium and stainless steel) were used, and diamond-like carbon (DLC) films were deposited on the wires. Three types of brackets, a conventional stainless steel bracket and two self-ligating brackets, were used for measuring static friction. DLC layers were observed by three-dimensional scanning electron microscopy (3D-SEM), and the surface roughness was measured. Hardness and elastic modulus were obtained by nanoindentation testing. Frictional forces and surface roughness were compared by the Kruskal- Wallis and Mann-Whitney U-tests. The hardness and elastic modulus of the wires were compared using Student's t-test. Results: When angulation was increased, the DLC-coated wires showed significantly less frictional force than the as-received wires, except for some wire/bracket combinations. Thin DLC layers were observed on the wire surfaces by SEM. As-received and DLC-coated wires had similar surface morphologies, and the DLC-coating process did not affect the surface roughness. The hardness of the surface layer of the DLC-coated wires was much higher than for the as-received wires. The elastic modulus of the surface layer of the DLC-coated stainless steel wire was less thanthat of the as-received stainless steel wire, whereas similar values were found for the nickeltitanium wires. Conclusions: The hypothesis is rejected. A DLC-coating process does reduce the frictional force.
Original language | English |
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Pages (from-to) | 143-150 |
Number of pages | 8 |
Journal | Angle Orthodontist |
Volume | 81 |
Issue number | 1 |
DOIs | |
Publication status | Published - 2011 Jan |
Externally published | Yes |
Keywords
- Diamond-like carbon coating
- Frictional properties
- Nanoindentation test
- Nickel-titanium
- Orthodontic wire
- Stainless steel
ASJC Scopus subject areas
- Orthodontics