Ultrafast-Laser-Processed Zirconia and its Adhesion to Dental Cement

Hard zirconia ceramic in its hot-isostatically pressed constitution can be machined precisely and reproducibly using ultrafast lasers. However, the pulse overlap turns out to be of significant influence on the resulting surface quality. This can be traced back to particulate process emission from the workpiece surface that influences subsequent pulses in the case of large pulse overlapping and can even agglomerate to debris layers above the processed surface. Measurements of particle emission indicate that 90 % of the ablated particulate material consists of nanoparticles, raising the demands on safe machine housing and suction measures. To produce all-ceramic dental crowns directly from sintered blanks without thermal damage or tool wear, a processing station, including a femtosecond laser system, has been designed based on high necessary processing dynamics and considering safety aspects.