Sprayed opaque porcelain as a retentive surface for resin-bonded restorations

This study investigated the shear bond strength between etched enamel and 4-mm-diameter base metal castings cemented with Panavia EX. Four different methods of casting preparation were used: air abraded, salt crystals placed on the wax patterns, opaque porcelain sprayed on the metal surface, and sprayed opaque porcelain followed by a silane coupling agent. The prepared surfaces were examined before and after testing using SEM and electron dispersive analysis by x-rays. It was determined that there was no significant difference in the shear bond strength between the salt-crystal technique and the nonsilanated sprayed ceramic surfaces. The air-abraded surface was the least retentive, and the silanated opaque porcelain specimens had intermediate retention. The sprayed opaque porcelain technique seems to offer several advantages.