Chairside CAD/CAM materials. Part 2: Flexural strength testing

In this study, the physical properties of a custom block manufactured using a self-polymerizing resin (Custom-block), the commercially available CAD/CAM PMMA disk (PMMA-disk), and a heat-polymerizing resin (Conventional PMMA) were evaluated via three different tests. The Custom-block was polymerized by pouring the self-polymerizing resin into a special tray, and Conventional PMMA was polymerized with a heat-curing method, according to the manufacturer’s recommended procedure. The specimens of each group were subjected to three-point bending, water sorption and solubility, and staining tests. The results showed that the materials met the requirements of the ISO standards in all tests, except for the staining tests. The highest flexural strength was exhibited by the PMMA-disk, followed by the Custom-block and the Conventional PMMA, and a significant difference was observed in the flexural strengths of all the materials (p < 0.001). The Custom-block showed a significantly higher flexural modulus and water solubility. The water sorption and discoloration of the Custom-block were significantly higher than those of the PMMA-disk, but not significantly different from those of the Conventional PMMA. In conclusion, the mechanical properties of the three materials differed depending on the manufacturing method, which considerably affected their flexural strength, flexural modulus, water sorption and solubility, and discoloration.

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Effects of Powdery Cellulose Nanofiber Addition on the Properties of Glass Ionomer Cement

Materials ◽

10.3390/ma12193077 ◽

2019 ◽

Vol 12 (19) ◽

pp. 3077 ◽

Cited By ~ 2

Author(s):

Takako Nishimura ◽

Yukari Shinonaga ◽

Chikoto Nagaishi ◽

Rie Imataki ◽

Michiko Takemura ◽

...

Keyword(s):

Flexural Strength ◽

Cellulose Nanofibers ◽

Glass Ionomer Cement ◽

Chemical Properties ◽

Fluoride Ion ◽

Strength Testing ◽

Glass Ionomer ◽

Ion Release ◽

Diametral Tensile Strength ◽

Ionomer Cement

In this study, we aimed to evaluate the effect of the addition of powdery cellulose nanofibers (CNFs) on the mechanical properties of glass ionomer cement (GIC) without negatively affecting its chemical properties. Commercial GIC was reinforced with powdery CNFs (2–8 wt.%) and characterized in terms of flexural strength, compressive strength, diametral tensile strength, and fluoride-ion release properties. Powdery CNFs and samples subjected to flexural strength testing were observed via scanning electron microscopy. CNF incorporation was found to significantly improve the flexural, compressive, and diametral tensile strengths of GIC, and the corresponding composite was shown to contain fibrillar aggregates of nanofibers interspersed in the GIC matrix. No significant differences in fluoride-ion release properties were observed between the control GIC and the CNF-GIC composite. Thus, powdery CNFs were concluded to be a promising GIC reinforcement agent.

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Flexural strength of CAD-CAM and conventional interim resin materials with a surface sealant

Journal of Prosthetic Dentistry ◽

10.1016/j.prosdent.2020.09.004 ◽

2020 ◽

Vol 124 (6) ◽

pp. 800.e1-800.e7

Author(s):

Gülce Çakmak ◽

Hakan Yilmaz ◽

Özge Aydoğ ◽

Burak Yilmaz

Keyword(s):

Flexural Strength ◽

Cad Cam ◽

Surface Sealant

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Effect of the bur grit size on the flexural strength of a glass-ceramic

Cerâmica ◽

10.1590/0366-69132016623621988 ◽

2016 ◽

Vol 62 (362) ◽

pp. 121-127 ◽

Cited By ~ 1

Author(s):

P. P. Kist ◽

I. L. Aurélio ◽

M. Amaral ◽

L. G. May

Keyword(s):

Surface Roughness ◽

Flexural Strength ◽

Glass Ceramic ◽

Glass Ceramics ◽

Internal Surface ◽

Grit Size ◽

Diamond Grit ◽

Cad Cam ◽

Negative Effect ◽

Ceramic Blocks

Abstract The purpose of the present study was to determine the biaxial flexural strength (BFS) of a CAD/CAM leucite reinforced glass-ceramic ground by diamond burs of different grit sizes and the influence of surface roughness on the BFS. For this, 104 plates were obtained from CAD/CAM ceramic blocks and divided into 4 groups (n = 26), according to bur grit size: extra-fine, fine, medium and coarse. Roughness parameters (Ra, RyMax) were measured, and plates were kept dry for 7 days. The flexural test was carried out and BFS was calculated. Ra, RyMax and BFS data were subjected to analysis of variance and post-hoc test. Weibull analysis was used to compare characteristic strength and Weibull modulus. Regression analysis was performed for BFS vs. Ra and RyMax. When burs with coarse grit were used, higher surface roughness values were found, causing a negative effect on the ceramic BFS (117 MPa for extra-fine, and 83 MPa for coarse). Correlation (r) between surface roughness and BFS was 0.78 for RyMax and 0.73 for Ra. Increases in diamond grit size have a significant negative effect on the BFS of leucite-reinforced glass-ceramics, suggesting that grinding of sintered glass-ceramic should be performed using burs with the finest grit possible in order to minimize internal surface flaws and maximize flexural strength.

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Effect of Sm2O3 Additives on the Rod-Like β-Si3N4 Crystal of Porous Silicon Nitride Fabricated by Reaction-Bonded

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.105-106.42 ◽

2010 ◽

Vol 105-106 ◽

pp. 42-45

Author(s):

Jian She Yue ◽

Hong Jie Wang

Keyword(s):

Silicon Nitride ◽

Porous Silicon ◽

Aspect Ratio ◽

Flexural Strength ◽

High Aspect Ratio ◽

Liquid State ◽

Theory Testing ◽

Strength Testing ◽

Xrd Diffraction ◽

Crystal Content

Sm2O3 and MgO as a sintering additives to fabricated porous silicon nitride by reaction-bonded. The phase of as-produced silicon nitride characterized by XRD-diffraction. The microstructure of product was investigated by SEM. The samples were machined into test bar for flexural strength testing. Using Archimedes theory testing the porosity of porous silicon nitride. MgO have restrain effect on the growth of rod-like silicon nitride, because of produce a restrain layer which is MgO reacted with SiO2 on the surface of silicon., the microstructure of crystal is particle like, the maximum flexural strength is 48MPa with porosity of 35%. Sm2O3 can assistant the growth of high aspect ratio Si3N4 crystal at beginning temperature of 1300°C for it’s low melt point and low viscidity in liquid state, the as-product’s morphology is rod-like and the flexural strength is as high as 300 MPa when the porosity is 30%, high than the sample that of low rod-like crystal content.

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