Hydrofluoric acid etching of dental zirconia. Part 1: etching mechanism and surface characterization

Rough surfaces have been shown to promote osseointegration, which is one of the keys for a successful dental implantation. Among the diverse treatments proposed to roughen zirconia, hydrofluoric acid (HF) etching appears to be a good candidate, however little is known about this process. In this work, the effect of HF concentration and etching time on the surface topography and chemistry of yttria-stabilized zirconia was assessed. Besides, to understand the etching mechanism, the reaction products present in solution and on the surface were characterized. The results indicate suitable parameters for a fast and uniform roughening of zirconia. The formation of adhered fluoride precipitates on the surface is reported for the first time and highlights the importance of cleaning after etching. Finally, it is shown that monitoring the time allows controlling the surface roughness, smooth–rough transition and fractal dimension, which should make possible the fabrication of implants with an optimal topography.