SINTERING ZIRCONIA FOR DENTAL CAD/CAM TECHNOLOGY

Zirconia has been recently introduced in prosthetic dentistry for the fabrication of crowns and fixed partial dentures, in combination with CAD/CAM techniques. To understand the clinical performance, it is important to establish the fundamental relationships between the intrinsic microstructural characteristics, mechanical properties and the machining properties. In this study, a series of zirconia blanks with systematically controlled pre-sintering stage were milled using a 4 axes CNC milling machine. The pre-sintering heating rate and temperature of the blanks affect in opposite manner hardness and machinability. Cutting condition, surface roughness, geometric accuracy and machining time were then optimized by varying cutting feed (mm/min), depth of cut (mm), and step offset (mm). Phase stability and mechanical properties of the products were re-assessed to understand the effect of machining damage.