EFFECTS OF THE POST-SINTERING PROCESS ONTHE BIAXIAL FLEXURALSTRENGTH OF MONOLITHIC ZIRCONIA

Abstract

This study investigated the biaxial flexural strength of monolithic zirconia after being subjected to various post-sintering processes. Fifty-eight zirconia discs (1.2±0.2 mm thickness and 14±0.2 mm diameter)were randomly divided into four groups:1) As glazed (AG), receiving only a surface glaze;2) Finished and polished (FP)3) Finished, polished, and overglazed (FPO);and 4)Finished, polished, and heat-treated (FPHt); Biaxial flexural strength was tested, giving means of± SD of 1,626.43±184.38, 1,734.98±136.15, 1,636.92±130.11 and 1,590.78 ±161.74 MPa for the AG, FP, FPO and FPHt groups, respectively.There was no statistical significance among the tested groups (p>0.05); however, the FP group demonstrated the highest flexural strength.Overglazing and heat treatment after polishing did not decrease flexural strength,though the complexity of both the equipment and the procedures necessitated inconvenient post-processing protocol for this clinical situation.