RESUMO
STATEMENT OF PROBLEM: The retention of zirconia ceramic posts to root canal dentin with resin-based luting cements is relatively poor. PURPOSE: The purpose of this in vitro study was to evaluate the effect of a new zirconia primer, a mixture of organophosphate and carboxylic acid monomers, on the push-out bond strength of zirconia posts to root canal dentin. MATERIAL AND METHODS: The root canals of 40 extracted human maxillary central incisors were endodontically treated and the post spaces were prepared. Zirconia posts were luted with 2 different resin luting agents (Panavia F and Clearfil SA luting cements) with and without the zirconia primer (Z-Prime Plus; Bisco). Three segments, each 2 mm high, were cut perpendicular to the post from each root. Bond strength was determined by pushing out the post with a universal testing machine. Three-way ANOVA and the Tukey HSD test was used to assess the effects of the zirconia primer, the 2 different resin luting cements, and different thirds of the root canal (α=.05). RESULTS: The zirconia primer significantly increased the push-out bond strength of zirconia posts to root canal dentin. Clearfil SA luting cement provided significantly higher bond strength than did Panavia F. For all experimental groups combined, bond strength decreased from the coronal to the apical section. CONCLUSIONS: A zirconia primer based on organophosphate/carboxylic acid monomers increased the bond strength of zirconia posts to root canal dentin bonded with both resin luting cements.
