The effect of alumina and aluminium nitride coating by reactive magnetron sputtering on the resin bond strength to zirconia core

PURPOSE: Although several surface treatments have been recently investigated both under in vitro and in vivo conditions, controversy still exists regarding the selection of the most appropriate zirconia surface pre-treatment. The purpose of this study was to evaluate the effect of alumina (Al) and aluminium nitride (AlN) coating on the shear bond strength of adhesive resin cement to zirconia core. MATERIALS AND METHODS: Fifty zirconia core discs were divided into 5 groups; air particle abrasion with 50 µm aluminum oxide particles (Al(2)O(3)), polishing + Al coating, polishing + AlN coating, air particle abrasion with 50 µm Al(2)O(3) + Al coating and air particle abrasion with 50 µm Al(2)O(3) + AlN coating. Composite resin discs were cemented to each of specimens. Shear bond strength (MPa) was measured using a universal testing machine. The effects of the surface preparations on each specimen were examined with scanning electron microscope (SEM). Data were statistically analyzed by one-way ANOVA (α=.05). RESULTS: The highest bond strengths were obtained by air abrasion with 50 µm Al(2)O(3), the lowest bond strengths were obtained in polishing + Al coating group (P<.05). CONCLUSION: Al and AlN coatings using the reactive magnetron sputtering technique were found to be ineffective to increase the bond strength of adhesive resin cement to zirconia core.