Influence of core thickness and artificial aging on the biaxial flexural strength of different all-ceramic materials: An <i>in-vitro</i> study

Abstract

The purpose of this study was to investigate the flexural strength of all-ceramics with varying core thicknesses submitted to aging. In-Ceram Alumina (IC), IPS e.max Press (EM) and Katana (K) (n=40), were selected. Each group contained two core groups based on the core thickness as follows: IC/0.5, IC/0.8, EM/0.5, EM/0.8, K/0.5 and K/0.8 mm in thickness (n=20 each). Ten specimens from each group were subjected to aging and all specimens were tested for strength in a testing machine either with or without being subjected aging. The mean strength of the K were higher (873.05 MPa) than that of the IC (548.28 MPa) and EM (374.32 MPa) regardless of core thickness. Strength values increased with increasing core thickness for all IC, EM and K regardless of aging. Results of this study concluded that strength was not significantly affected by aging. Different core thicknesses affected strength of the all-ceramic materials tested (p<0.05).

Fracture resistance and marginal fit of the zirconia crowns with varied occlusal thickness

“…Gierthmuehlen et al 26 also demonstrated that fracture loads of ceramics with thicknesses of 1.5 mm and 1 mm were similar, suggesting that 1 mm ceramic thickness was reliable even in the posterior restorations. Dikicier et al 27 demonstrated that the fracture strength of zirconia increased with the thickness (from 0.5 mm to 0.8 mm), and both were not affected by aging. The fracture strength of the zirconia increases with the occlusal thickness; however, even thinner zirconia restorations have adequate fracture strength, reported by Yin et al 28 demonstrating a fracture strength greater than 1500 N and 2500 N in 0.5 mm and 1.00 mm zirconia, respectively.…”

Microstructural analysis and reliability of monolithic zirconia after simulated adjustment protocols

“…It is known that monolithic zirconia crowns exhibit greater fracture resistance than bilayered ones [16] and that the thickness of full contour ceramic restorations influences fractures resistance [17]. According to the ISO 6872:2015 [7], specimens for the biaxial flexural strength test should have a diameter of 12 mm and a thickness of 1.2 mm, but the literature presents several papers that used Y-TZP specimens or other ceramics in dimensions other than those required by ISO for biaxial flexural tests [18][19][20][21][22][23][24][25][26]. Due to a limitation of the fatigue equipment in load application levels, this work used 0.8 mm thick samples after monotonically testing samples of varying thicknesses of 0.6 to 1.4 mm in a pilot study.…”

Evaluation of wear and fracture strength of zirconia-based ceramics and metal-supported ceramics after treatment with the chewing simulator

“…As for Katana, studies reported resistance against aging and high physical properties such as low PT, high flexural strength even with 0.2 mm thickness [28,30]. Also, Dikicier et al [36] demonstrated that flexural strength and fracture strength of Katana zirconia increased with the thickness of the material (from 0.5 mm to 0.8mm) and both of them was not affected by aging. In contrast, despite samples with higher thickness, Katana exhibited lower features compared to other materials.…”