Does metal coating improve the durability of silicone voice prostheses?

Voice prostheses, which are used for voice rehabilitation in cancer patient s after laryngectomy, usually become colonized with a mixed biofilm of bact eria and Candida after 2-4 months and lose their efficiency. It is essentia l to ensure the stability and biocompatibility of these implants. With the aid of surface frame analysis we have shown that local antifungal treatment is inadequate for eliminating the deep infiltration and encapsulation of C andida colonies in silicone. A surface that prevents the adhesion of microo rganisms is required. Because of its special properties there are few metho ds available for coating silicone. We employed, for the first time, a new m ethod of surface modification using anodic vacuum arc coating. Using this m ethod it was possible to obtain a solid film of gold or titanium metal with a layer thickness < 100 nm. Resistance against Candida colonization and de struction of coated prostheses were tested both in vitro and in vivo. A tit anium coating seemed to provide the optimal solution to the problem, becaus e surface adhesion and the smoothness of the material appeared to be superi or to those of a gold coating.