Low temperature growth of thin film coatings for the surface modification of dental prostheses

In this work we present some results about the low temperature, plasma-assisted growth of silicon-oxygen amorphous thin film alloys (a-SiO(x)) on different types of dental materials used for the fabrication of dental prostheses. The a-SiO(x) films were grown at substrate temperatures lower than 70 degrees C by a PECVD deposition system using silane (SiH(4)) and nitrous oxide (N(2)O) as precursor gases. The chemical bonding structure of the films was investigated by Fourier transform infra-red spectroscopy (FTIR), while the morphological characteristics of the dental materials were analyzed before and after the coating deposition by means of high-resolution mechanical profilometry. The surface energy of dental materials was estimated before and after the coating process by contact angle measurements, revealing that the coating produced a considerable change of surface energy in all the tested samples, evidenced by a contact angle reduction from more than 90 degrees to less than 10 degrees. Some tests were also performed to estimate the effect of the coating on the bacterial adhesion properties, revealing that the a-SiO(x) coatings show some effectiveness in reducing the bacterial adhesion on the dental materials surface. (C) 2007 Elsevier B.V. All rights reserved.