Effect of three adhesive primers for a noble metal on the shear bond strengths of three resin cements

The purpose of this study was to evaluate the durability and shear bond str engths of the different combinations of three adhesive primers and three re sin cements to a silver-palladium-copper gold (Ag-Pd-Cu-Au) alloy. The adhe sive primers Alloy Primer(R) (AP), Metal PrimerII(R) (MPII) and Metaltite(R ) (MT), and the resin cements BistiteII(R) (BRII), Panavia Fluoro Cement(R) (PFC) and Super-Bond C&B(R) (SB) were used. Two sizes of casting alloy dis ks were either non-primed or primed and cemented with each of the three res in cements. The specimens were stored in a 37 degreesC water bath for 24 h and then immersed alternately in 4 and 60 degreesC water baths for 1 min ea ch for up to 100000 thermal cycles. Shear mode testing at a crosshead speed of 0.5 mm/ min was then performed. The application of MPII or MT was effec tive for improving the shear bond strength between each of the three resin cements and the Ag-Pd-Cu-Au alloy compared with non-primed specimens. Howev er, when primed with MPII or MT and cemented with SB, the bond strength at 100000 thermal cycles was significantly lower than that at thermal cycle 0. When primed with AP, the specimens cemented with BRII or PFC showed lower bond strength than non-primed specimens and failed at the metal-resin cemen t interface at 100000 thermal cycles. On the other hand, AP was effective i n enhancing the shear bond strength of SE to the Ag-pd-Cu-Au alloy. The fiv e combined uses of an adhesive metal primer and resin cement (combinations of MPII or MT and BRII or PFC and AP and SB) are applicable to the cementat ion of prosthodontic restorations without complicated surface modification of the noble alloy.