Magnetron sputtered tin coatings on unbiased ceramic substrates

Objectives. The aim of this work was to study the application of tin oxide coatings on alumina, with a view to developing improved bonding for high-alumina dental ceramics. Methods. By use of a magnetron sputtering technique, alumina was coated with tin which was subsequently oxidized, and the bond strength of coated surfaces to a resin-based dental cement was measured in tension. Tensile bond strength data were assessed for their degree of skewness and the homogeneity of the residual variances with a view to applying appropriate transformations prior to performing ANOVA with subsequent Tukeyʹs analysis as necessary. The color of coatings, as a function of the amount of oxidation of the surface, was noted. Coatings were characterized by SEM and EDAX. It has been found possible to produce esthetic tin oxide coatings on alumina using a simplified magnetron sputtering apparatus in conjunction with post-deposition oxidation. Results. Although mean tensile bond strength (TBS) values in excess of 15 MPa were recorded for a number of groups, no causal relationship was found between coating time and mean TBS. Significance. The need exists for improved bonding of alumina-based ceramics; further development of a magnetron sputtering technique may provide the means for achieving this.