Ultrafast high‐temperature sintering of dental grade 4YSZ ceramics: Effects on microstructure and flexural strength

Abstract This study compares the effects of ultrafast high‐temperature sintering (UHS) and conventional sintering on the microstructural and mechanical properties of 4 mol% yttria‐stabilized zirconia, a ceramic widely used in dental restorations for its high strength, biocompatibility, and aesthetic qualities. UHS enabled full densification in just 5 min—a significant reduction compared to the 10‐h cycle required for conventional sintering. Both methods yielded similar relative densities (>96%); however, UHS stabilized the tetragonal phase and resulted in a slight reduction in flexural strength. Microstructural analysis revealed coarser surface grains in UHS specimens, indicating distinct grain growth kinetics under rapid heating conditions. Despite the reduction in strength, UHS‐sintered samples met the ISO 6872 minimum flexural strength requirement (>300 MPa), confirming their clinical applicability. These findings support UHS as a viable, time‐efficient alternative for processing dental zirconia, with potential for high‐throughput applications in restorative dentistry.