Shear bond strength of veneering composite resin to titanium nitride coating alloy deposited by radiofrequency sputtering

Objective The success of dental restorations utilizing composite resin over cast alloy has been variable and affected by micro-leakage. The purpose of this study was to investigate the shear bond strength between a composite resin and cast dental alloy coated with a layer of titanium nitride (TiN). Methods Cast disk specimens made of Au–Pd–Ag alloy were randomly divided into four groups. The first group was left uncoated as a control while one group was coated with a metal conditioner, and the other two were coated with TiN at either 200 or 500 W with a radiofrequency magnetron sputtering system. Each group was then bonded to one of two types of light-activated composite resin material. Shear bond strengths were tested and compared for each specimen. The bond strength of each group was analyzed by 2-way ANOVA and by post hoc multiple comparison tests (Fisherʹs PLSD). Results As the interaction among groups was not significant (p=0.27) by 2-way ANOVA, TiN coated groups were found to have improved shear bond strength compared with non-coated groups without metal conditioner for both resin composite materials by multiple comparison tests. Furthermore, TiN coating is significantly stronger than non-coated groups with metal conditioner for one of the two resin composite materials examined (p<0.01). Conclusions The results suggested that metal surface modification by coated TiN represents a technique that may significantly improve the bond between the Au–Pd–Ag alloy and veneering resin composite.