3D Profilometry Characterization of Zirconia Ceramic After Different Surface Pretreatments

Objectives: The aim of our study was to assess the surface roughness of zirconia after different pretreatment procedures by means of 3D Profilometry.
Methods: Ten groups of yttria-stabilized KATANA™ Zirconia (Kuraray Noritake Dental Inc.) samples were prepared: one control group (no pretreatment); four groups sandblasted by 50 μm and 250 μm Al₂O₃ particles at a pressure of 2 and 4 bars; three Er:YAG laser groups irridated with energy intensity of 100, 200 and 400 mJ and two groups treated with HF (hydrofluoric acid) of 10% and 40% concentration.
Results: 3D images were processed by means of 3D profilometer Zeta-20 and the roughness in all dimensions in µm was measured. For every specimen Ra (arithmetic mean roughness) and Rq (root-mean-square roughness) were estimated. The control group was heterogenic in nature (Ra 0.33; Rq 0.41) and its roughness was similar to the groups treated with 40% (Ra 0.33; Rq 0.42) and 10% HF (Ra 0.35; Rq 0.45), that confirms HF pretreatment as an ineffective protocol. Irradiation by Er:YAG laser showed results close to the control and HF groups in different modes of applied energy: 100 µJ (Ra 0.31; Rq 0.42); 200 µJ (Ra 0.35; Rq 0.45); 400 µJ (Ra 0.35; Rq 0.45). The highest roughness was observed on samples sandblasted by 50 μm Al₂O₃ at a pressure of 4 bars: Ra 0.57; Rq 0.70. The rest of the sandblasting methods also showed high rates of performance: 50 μm Al₂O₃, 2 bars: Ra 0.45; Rq 0.57; 250 μm Al₂O₃, 4 bars: Ra 0.41; Rq 0.53 and 250 μm Al₂O₃, 2 bars: Ra 0.38; Rq 0.49.
Conclusions: Within the limitations of our study, sandblasting by Al₂O₃ results in the highest roughness and seems to be an effective method for surface pretreatment of zirconia.