SEM observation and wettability of variously processed and fractured surface of dental zirconia

► Zirconia surface after various treatments was analyzed by SEM, contact angle and surface roughness measurement, and compared. ► Both mirror polishing and porcelain layering look similarly smooth. ► 24-h acid treatment induced much more surface roughening with the 50-100 nm particulate roughness than tribochemical treatments. ► Experimentally attained fracture surfaces cracks were formed straight in most part and in some places curved or twisted into S or Ω form. ► Clinically occurred fracture exhibited the scab-like surface.