Mechanical Properties of Polymer-Infiltrated-Feldspar for Restorative Composite CAD/CAM Blocks

Polymer-infiltrated-feldspar used for restorative composite CAD/CAM blocks were prepared by infiltrating polymerizable monomers into the partially sintered feldspar blocks. The flexural strength was tested according to the standard of ISO-4049. The micro-structure was examined by SEM. The effects of sintering temperature, high pressure and the addition of SiO2 and Al2O3 on the ultimate flexural strength were evaluated. The flexural strength corresponding to infiltration with pressure was much higher than that without pressure at high sintering temperature. The addition of SiO2 and Al2O3 into the natural feldspar mineral increased the flexural strength of the blocks significantly.