Two-step sintering suppresses grain growth and improves flexural strength of dental zirconia

Autor(es)

Lim, Chek Hai ; Alves, Larissa M. M. ; Vardhaman, Sonaj ; Bonfante, Estevam A. ; Kim, Do Kyung ; Zhang, Yu

• Tipo de documento: Artigo Científico
• Fonte: Dental Materials; v. 41, n. 2, p. 9-pg., 2025-01-16.

Resumo

Objectives: This study aimed to elucidate the effect of various two-step sintering (TSS) protocols on the physical, mechanical, and optical properties of partially stabilized zirconia with different yttria dopant concentrations (YPSZ). Methods: Disc-shaped specimens were obtained from most widely used commercial dental zirconia powders of various Y contents (Tosoh Corp.) by uniaxial pressing followed by cold-isostatic pressing. Densification was carried out using TSS protocols with varying temperatures for both sintering steps. Relative density (rho Rel), microstructure, and phase content were analyzed. Biaxial flexural strength (6) and translucency parameter (TP) were evaluated. Results: The TSS results were compared with optimized conventional sintering (CS) results from a previous study for the same Y-PSZ compositions. TSS 3Y-PSZ and 4Y-PSZ reached similar rho Rel to those of their CS counterparts, whereas 5Y-PSZ failed to achieve that regardless of TSS protocol. TSS yielded less cubic phase compared to CS, especially for 3Y-PSZ and for higher temperatures. TSS suppressed the grain growth throughout the temperature range investigated, promoting smaller grains than CS (p < 0.05). The TP values for TSS Y-PSZ were lower than those of CS (p < 0.0001), except for 3Y-PSZ. The 6 values for TSS Y-PSZ were significantly higher than those of CS (p < 0.0002). Significance: TSS increased strength without significantly jeopardizing the optical properties of various Y-PSZ compositions relative to their CS counterparts. This alternative sintering method appears to be a promising technique for controlling grain growth while eliminating porosities in dental Y-PSZ ceramics, thus potentially enhancing the clinical longevity of zirconia restorations. (AU)

• Processo FAPESP: 21/07440-2 - Infiltração graduada por vidro em uma zircônia ultra translúcida (5Y-PSZ): síntese, processamento e caracterização das propriedades físicas e mecânicas
• Beneficiário: Larissa Marcia Martins Alves
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado
• Processo FAPESP: 21/06730-7 - Rumo à zircônia sustentável reciclada a partir do descarte de usinagem e melhorada por infiltração graduada e ao desenvolvimento de blocos de zircônia multicamada resistentes, graduados, e não suscetíveis ao envelhecimento
• Beneficiário: Estevam Augusto Bonfante
• Modalidade de apoio: Auxílio à Pesquisa - Jovens Pesquisadores - Fase 2
• Processo FAPESP: 23/07289-8 - Influência da degradação em baixa temperatura na resistência ao desgaste de uma zircônia translúcida reciclada
• Beneficiário: Larissa Marcia Martins Alves
• Modalidade de apoio: Bolsas no Exterior - Estágio de Pesquisa - Pós-Doutorado