Abstract
The purpose of this study was to develop a new method of releasing fluorine in a controlled manner for applications in the field of orthodontic Ti‐based wire, namely the coating of fluorides on Ti. Thin films of two fluoride compounds, CaF~2~ and MgF~2~, were coated on Ti via the electron‐beam evaporation method. The fluorine was released rapidly from the as‐deposited MgF~2~ coating within a short period~,~ and then the release rate slowed down. When the MgF~2~ coating was heat treated, this initial burst effect was decreased, but a significant amount of cracks were generated. On the other hand, in the case of the as‐deposited CaF~2~ coating, fluorine was released linearly for the entire period, without an initial burst. In the heat‐treated CaF~2~ coatings the trend was similarly observed. The linear fluorine release from the CaF~2~ coatings, even in the as‐deposited state, was attributed to the high degree of crystallinity of the coatings. A preliminary cell test showed favorable cell viability on both the fluoride coatings. Given their sustained and controlled fluorine release, these fluoride coatings, particularly CaF~2~, are suggested to be potentially useful in the field of orthodontic Ti‐based wire. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2005