Surface characterization of monolithic zirconia submitted to different surface treatments applying optical interferometry and raman spectrometry.

This study evaluated roughness parameters and phase transformation of monolithic zirconia ceramics after various mechanical and laser thermal treatments. Fully sintered monolithic zirconia cylinder specimens were divided to five groups, according to the applied surface treatment: CL: control, GB: grit-blasted with glass particles. AL50: grit-blasted with 50 μm alumina particles, AL90: grit-blasted with 90 μm dyed-alumina particles and FEML: subjected to femto laser thermal treatment. Six roughness parameters (Sa, Sq, Sz, Sci, Svi and Sdr) were measured by optical profilometry. Phase transformation in zirconia was determined by micro-Raman spectroscopy. The highest roughness values were recorded in AL90 and FEML groups, followed by AL50. AL90 presented statistically higher monoclinic phase content compared to all other groups. Control and GB groups presented similar roughness without phase transformation. Laser thermal treatment causes minimal destruction of the zirconia surface, and can be suggested as an alternative to other roughening treratments, for enhancing the adhesive potential to dentin.