File-splitting multilayer vs monolithic Y-TZP: Fatigue flexural strength and loading stresses by finite element analysis

Marchionatti, Ana Maria Estivalete; Wandscher, Vinícius Felipe; Aurélio, Iana Lamadrid; Bergoli, César Dalmolin; May, Liliana Gressler

doi:10.1016/j.dental.2019.01.014

Cited by 14 publications

(14 citation statements)

References 56 publications

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“…The three‐point bending flexural strength values were determined to be in the range of 721.45 MPa (LT/C) and 306.44 MPa (HT/I). These numbers are in agreement with previous studies evaluating the mechanical performance of materials with different levels of translucency (Marchionatti, Wandscher, Aurélio, Bergoli, & May, ; Stawarczyk et al, ). Analysis of the results indicated that there was a significant difference ( p < .001) in FS values between LT (721.45–588.40 MPa) and HT (339.77–306.44 MPa) materials.…”

Section: Discussionsupporting

confidence: 92%

Effect of ionizing radiation on mechanical properties and translucency of monolithic zirconia

Alshamrani

Souza

2019

J Biomed Mater Res

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This study aimed to evaluate the effect of radiation therapy (RT) on mechanical properties and translucency of monolithic zirconia. Yttria‐ stabilized zirconia (Y‐PSZ) materials (14 × 4.0 × 1.5 mm) were divided in four experimental groups (n = 30): High‐translucency/control (HT/C), high‐translucency/irradiated (HT/I), low‐translucency/control (LT/C), low‐translucency/irradiated (LT/I). Irradiated specimens were submitted to a single dose irradiation of 70 Gray. Flexural strength (n = 10) (FS—3‐point bending test), fatigue limits (n = 15) at 100,000 cycles (FLs—staircase approach), and translucency (n = 5) (TP—dental spectrometer) were analyzed. X‐ray diffraction (XRD) and scanning electron microscopy (SEM) were used to characterize the materials. FS and TP data were analyzed by one‐way Analysis of Variance (ANOVA) and Tukey HSD. FLs were analyzed using Dixon and Mood method, and Kaplan–Meier survival analysis. RT affected FS of LT zirconia (p = .032) but not of HT zirconia (p = .86). FLs and TP of both materials were not affected by RT (p > .05). Higher cubic content after RT was observed. In conclusion, RT may affect flexural strength and crystalline content of zirconia‐based materials, but this effect was not observed under fatigue. Translucency of Y‐PSZ restorations is also not affected by RT.

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Section: Discussionsupporting

confidence: 92%

Effect of ionizing radiation on mechanical properties and translucency of monolithic zirconia

Alshamrani

Souza

2019

J Biomed Mater Res

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“…We adopted a fatigue testing scenario, recommended by ISO, that successfully resulted on the desired pattern of failure, that was the crack of the veneer without complete fracture of the set. Besides this testing assembly has already been at prior used by published articles of similar thematic [27,28]. Clinically there has been seen with this kind of restorations high incidence of chipping and delamination [29].…”

Section: Discussionmentioning

confidence: 99%

Fatigue behavior and colorimetric differences of a porcelain-veneered zirconia: effect of quantity and position of specimens during firing

et al. 2021

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Purpose: To evaluate the influence of quantity and positioning of veneered zirconia specimens during firing of porcelain on their fatigue performance and colorimetric differences. Methods: Bilayer discs (Ø=15 mm) were made, following ISO 6872 guidelines, using a Y-TZP core (yttria-stabilized tetragonal zirconia polycrystal ceramic; VITA In-Ceram YZ) and a feldspathic veneering material (VITA VM9), being both layers with 0.7 mm thickness. Y-TZP discs were sintered, the veneering material was applied over it, and the bilayer specimens were fired according to two factors (n=20): 'quantity' (1 or 5 samples per firing cycle; G1 and G5 groups respectively) and 'positioning' of the specimens inside the furnace (center or periphery of the refractory tray; G5C and G5P groups, respectively). The CIEL*a*b* parameters were recorded with a spectrophotometer and the color difference (ΔE 00) and translucency (TP 00) were calculated using CIEDE2000 equations. The step-stress fatigue test was performed with the veneer facing down (region of tensile stress concentration), 10 Hz frequency, initial tension of 20 MPa for 5,000 cycles, followed by steps of 10,000 cycles using a step size of 10 MPa, up to 100 MPa; data from strength and number of cycles for failure were recorded for statistical analysis. Results: Unacceptable color differences (ΔE 00 >1.8) were observed comparing G5C vs. G1 (quantity) and G5C vs. G5P (positioning), meanwhile translucency parameters were not affected. Besides, only the 'quantity' factor influenced the fatigue performance (G1>G5C). None of the tested specimens survived beyond 90N and/or 75000 cycles. Conclusions: The quantity and position of the specimens during firing influence the final color of porcelain-veneered zirconia, and firing one specimen per cycle improved the fatigue performance of the bilayer system.

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“…behavior under flexural strength test depends on the characteristics of the material positioned as the bottom surface, so if the porcelain takes place under tensile stress, the set strength could be even similar to a monolithic veneering ceramic [22,37]. Thus, the ultimate strength and failure mode is mainly dictated by the material properties on the bottom, which in this case is the porcelain, and the contribution of the Y-TZP core results in just a modest increase in the strength [38].…”

Section: Control Grindingmentioning

confidence: 99%

“…It is important to consider that the presence of pores may facilitate crack propagation towards to the interface [37,47,48]. Thus, if a surface treatment, as grinding, generates more homogeneous surfaces with defects that are easier to be filled by the porcelain (Fig.…”

Section: Groupsmentioning

confidence: 99%

“…Under the conditions explored herein, the strong control and methodological standards induces a reduced presence of internal pores and defects on porcelain layer. Previous studies have reported that the hand-layered technique generates more porosities at vitreous ceramics [37,47], and these defects may decrease the mechanical performance of the material, according to the Griffith's law [48]. Thus, on a clinical setup if during porcelain application higher bubbles and defects are introduced, the performance of the set may be influenced.…”

Section: Groupsmentioning

confidence: 99%

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Influence of zirconia surface treatments of a bilayer restorative assembly on the fatigue performance

et al. 2021

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This study evaluated the influence of different surface treatments of zirconia used to enhance bonding with veneering porcelain, and thermocycling on the resistance to porcelain cracking and delamination during fatigue test. Methods: Bilayer ceramic discs were made from zirconia blocks (IPS e.max Zircad MO, Ivoclar Vivadent-0.7 mm thickness) and randomized into 8 groups (n= 15) according to two factors: 'zirconia surface treatment' (Control; Grinding-diamond bur; Air-abrasion-aluminum oxide particles; and Liner-application of a ceramic liner [IPS e.max Zirliner, Ivoclar Vivadent]); and 'thermocycling' (presence-12,000 thermal cycles; 5-55ºC; or absence). The discs were veneered with porcelain (IPS e.max Ceram, Ivoclar Vivadent-0.7 mm; totaling 1.4 mm thickness) according to ISO 6872:2015 for biaxial flexure strength testing. Fatigue tests (step-stress approach; 20 to 100 MPa; step of 10 MPa; 10,000 cycles per step; 10 Hz frequency) were run, followed by the data analysis (Kaplan-Meier and Mantel-Cox post-hoc tests). Analysis of roughness, topography, crystallographic phase arranges and fractography were also executed. Results: The surface treatment and thermocycling did not influence the porcelain crack nor delamination resistance. When only comparing the surface treatments for crack resistance outcome, the liner application depicted the worst fatigue performance in comparison to grinding and air-abrasion, while all groups were similar for delamination. Conclusions: Neither the surface treatment of the zirconia nor the thermocycling influences the porcelain crack resistance or the resistance to delamination of the bilayer porcelain-veneered zirconia specimens.

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File-splitting multilayer vs monolithic Y-TZP: Fatigue flexural strength and loading stresses by finite element analysis

Cited by 14 publications

References 56 publications

Effect of ionizing radiation on mechanical properties and translucency of monolithic zirconia

Effect of ionizing radiation on mechanical properties and translucency of monolithic zirconia

Fatigue behavior and colorimetric differences of a porcelain-veneered zirconia: effect of quantity and position of specimens during firing

Influence of zirconia surface treatments of a bilayer restorative assembly on the fatigue performance

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