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Flexural Strength of Different Monolithic Computer-Assisted Design and Computer-Assisted Manufacturing Ceramic Materials upon Different Thermal Tempering Processes

Objective  Strength of ceramics related with sintering procedure. This study investigated the influence of different tempering processes on flexural strength of three monolithic ceramic materials. Materials and Methods  Specimens were prepared in bar-shape (width × length × thickness = 4 × 14 × 1.2...

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Detalles Bibliográficos
Autores principales: Juntavee, Niwut, Uasuwan, Pithiwat
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Thieme Medical and Scientific Publishers Private Ltd. 2020
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7535961/
https://www.ncbi.nlm.nih.gov/pubmed/32791528
http://dx.doi.org/10.1055/s-0040-1713957
Descripción
Sumario:Objective  Strength of ceramics related with sintering procedure. This study investigated the influence of different tempering processes on flexural strength of three monolithic ceramic materials. Materials and Methods  Specimens were prepared in bar-shape (width × length × thickness = 4 × 14 × 1.2 mm) from yttria-stabilized tetragonal zirconia polycrystalline (Y-TZP, inCoris TZI [I]), zirconia-reinforced lithium silicate (ZLS, Vita Suprinity [V]), and lithium disilicate (LS (2) , IPS e.max CAD [E]), and sintered with different tempering processes: slow (S), normal (N), and fast (F) cooling procedure ( n = 15/group). Flexural strength (σ ) was determined using three-point bending test apparatus at 1 mm/min crosshead speed. Statistical Analysis  The analysis of variance and Bonferroni’s multiple comparisons were determined for significant difference (α = 0.05). Weibull analysis was applied for survival probability, Weibull modulus (m), and characteristics strength (σ (o) ). Microstructures were evaluated with scanning electron microscope and X-ray diffraction. Results  The mean ± standard deviation (MPa) of σ, m, and σ (o) were: 1,183.98 ± 204.26, 6.23, 1,271.80 for IS; 1,084.43 ± 204.79, 5.76, 1,170.08 for IN; 777.19 ± 99.77, 8.78, 819.96 for IF; 267.15 ± 32.71, 9.11, 281.48 for VS; 218.43 ± 38.46, 6.40, 234.23 for VN; 252.67 ± 37.58, 7.20, 269.23 for VF; 392.09 ± 37.91, 11.37, 409.23 for ES; 378.88 ± 55.38, 7.45, 403.11 for EN, and 390.94 ± 25.34, 16.00, 403.51 for EF. Thermal tempering significantly affected flexural strength of Y-TZP ( p < 0.05), but not either ZLS or LS (2) ( p > 0.05). Y-TZP indicated significantly higher flexural strength upon slow tempering than others. Conclusion  Enhancing flexural strength of Y-TZP can be achieved through slow tempering process and was suggested as a process for monolithic zirconia. Strengthening of ZLS and LS (2) cannot be accomplished through tempering; thus, either S-, N-, or F- tempering procedure can be performed. Nevertheless, to minimize sintering time, rapid thermal tempering is more preferable for both ZLS and LS (2) .