Current dental zirconia has several problems in clinical application such as chipping, fracture and detachment. To reduce these problems the surface after various treatments was analyzed by SEM observation, contact angle measurement and surface roughness measurement, and compared. The surface after mirror polishing was smooth. Porcelain layering was smooth except large formed grooves by bubbles. After sandblast and tribochemical treatments, the surfaces showed several micron-sized caving with micron to submicron-level irregularities. Sandblast and tribochemical treatments with the lager roughness had the smaller water contact angle than silicone wheel polishing. Clinically fractured surface of zirconia showed a more complex structure than manually fractured surface, which may be due to the various mode of stress to be imposed repetitively to various direction. (c) 2012 Elsevier B.V. All rights reserved.