Laser-assisted Machining of Zirconia Ceramics using a Diamond Bur

Yttria-stabilized tetragonal zirconia polycrystal is a promising material for dental restoratives. The dominant manufacturing method of the dental restoratives comprises three steps. (1) Pressing (2) machining (3) final sintering. The method has disadvantages such as low geometrical accuracy and long process time in the final sintering stage. Thus, the direct machining method of the fully sintered Y-TZP which is difficult to machine is desired to realize an accurate, efficient and inexpensive fabrication process of the dental restoratives. We applied the laser-assisted machining process to machine fully sintered Y-TZP blocks. The tool adopted was diamond burs. A series of grinding experiments were conducted to assess the effectiveness of the laser assistance. The results revealed that the grinding force was reduced and the tool damage was reduced in the assisted processes while microcracks were observed on the surface. The conditions for the crack initiation was discussed. The laser-assisted grinding of Y-TZP was revealed to be effective for an efficient and relatively rough grinding process.