Wettability characteristics of an Al2O3/SiO2-based ceramic modified with CO2, Nd : YAG, excimer and high-power diode lasers

The interaction of CO2, Nd:YAG, excimer and high-power diode laser (HPDL) r adiation with the surface of an Al2O3/SiO2 based ceramic was found to effec t significant changes in the wettability characteristics of the material. I t was observed that interaction with CO2, Nd:YAG and HPDL radiation reduced the enamel contact angle from 118 degrees to 31 degrees, 34 degrees and 33 degrees respectively. In contrast, interaction with excimer laser radiatio n resulted an increase in the contact angle to 121 degrees. Such changes we re identified as being due to (i) the melting and partial vitrification of the Al2O3/SiO2-based ceramic surface as a result of interaction with CO2, N d:YAG and HPDL radiation; (ii) the surface roughness of the Al2O3/SiO2-base d ceramic increasing after interaction with excimer laser radiation; and (i ii) the surface oxygen content of the Al2O3/SiO2-based ceramic increasing a fter interaction with CO2, Nd:YAG and HPDL radiation. The work has shown th at the wettability characteristics of the Al2O3/SiO2-based ceramic could be controlled and/or modified by laser surface treatment, in particular, whet her the laser radiation had the propensity to cause surface melting. Howeve r, a wavelength dependence of the change of the wetting properties could no t be deduced from the findings of this work.