Surface characterization of anodized dental archwires and miniscrews

β-Ti dental archwires and Ti-6Al-4V miniscrews are anodized. The anodized archwires and miniscrews display various colors, and the colors are primarily controlled by the anodized voltage. The anodized surface is mainly titanium oxide. For most of the anodization conditions, the oxide layers are amorphous. With longer anodization time and more severe anodized conditions, the titanium oxide layers become partially crystalline, and the archwires and miniscrews are with milky white color. The oxide layer thickness was measured using TEM, AEM and calculation based on colors. The oxide layer grows with anodization time, and the thickness reaches a plateau value. The plateau thickness of the reaction layer depends linearly upon the applied voltage. With the addition of NaF in the electrolytes, nanotubes are observed on the surface after anodization.