Ceramic surface preparations for resin bonding.

PURPOSE: To evaluate the effects of hydrofluoric acid (HF) and acidulated phosphate fluoride (APF) primers on differently prepared leucite-containing feldspar ceramic surfaces.
MATERIALS AND METHODS: Discs of a leucite-containing feldspar ceramic were prepared following the manufacturer's instructions. Surfaces were either polished, grit blasted or prepared with a diamond bur and then subjected to a range of etching procedures using HF or APF. The surface topography was examined using scanning electron microscopy (SEM). Back-scattered imaging, EDS and X-ray diffraction (XRD) were used for microstructural and compositional analysis.
RESULTS: The etching process with HF consisted of a preferential attack of the leucite phase relative to the glass but also removed all features of the previous surface preparation. In contrast, APF etching resulted in the formation of surface deposits, superimposed on the surface roughness created by the prior surface preparations. It was not possible to identify the deposits after APF etching using XRD.