scholarly journals Influence of the Sintering Type in Ceramics Blocks for Cad-Cam

2016 ◽  
Vol 18 (2) ◽  
pp. 91
Author(s):  
Martín Kreisler DDS, MSc, PhD ◽  
Osmir Oliveira DDS, MSc, PhD
Keyword(s):  
Solid State ◽  
Flexural Strength ◽  
Liquid State ◽  
Hardness Test ◽  
Test Method ◽  
Bending Test ◽  
Three Point Bending ◽  
Cad Cam ◽  
Ceramic Blocks ◽  
State Group

The aim of this study was to characterize the influence of the sintering type in the flexural strength and hardness of ceramic blocks for CAD-CAM.  Four type of ceramic blocks were selected and distributed according to the  type of sintering to be performed: Group G1 - In-Ceram® Alumina / liquid state; Group G2 - In-Ceram® AL / solid state; Group G3 - In-Ceram® Zircon / liquid state; Group G4 - In-Ceram® YZ / solid state. All blocks were cut in bar shape with dimensions of 25 x 5 x 2 mm.  and submitted to the three-point bending test and to the Vickers hardness test method.  The results, after statistical analysis, showed  that the average flexural strength of group G1 (351.7 MPa) and group G3 (356.3 MPa) were significantly lower than those of group G2 (421.9 MPa) and group G4 (758.4 MPa); as well as all hardness averages were significantly different, being higher for group G2 (1.936,6 HV) and group G4 (1.321,4 HV), when compared to group G1 (1.173,3 HV) and group G3 (1.094,6 HV).  It was concluded that the solid state sintering proved to be more efficient to obtain maximum densification of the ceramics blocks, resulting in high values of flexural strength and hardness.

scholarly journals Influence of the Sintering Type in Ceramics Blocks for Cad-Cam

2016 ◽  
Vol 18 (2) ◽  
pp. 91
Author(s):  
Martín Kreisler DDS, MSc, PhD ◽  
Osmir Oliveira DDS, MSc, PhD
Keyword(s):  
Solid State ◽  
Flexural Strength ◽  
Liquid State ◽  
Hardness Test ◽  
Test Method ◽  
Bending Test ◽  
Three Point Bending ◽  
Cad Cam ◽  
Ceramic Blocks ◽  
State Group

The aim of this study was to characterize the influence of the sintering type in the flexural strength and hardness of ceramic blocks for CAD-CAM.  Four type of ceramic blocks were selected and distributed according to the  type of sintering to be performed: Group G1 - In-Ceram® Alumina / liquid state; Group G2 - In-Ceram® AL / solid state; Group G3 - In-Ceram® Zircon / liquid state; Group G4 - In-Ceram® YZ / solid state. All blocks were cut in bar shape with dimensions of 25 x 5 x 2 mm.  and submitted to the three-point bending test and to the Vickers hardness test method.  The results, after statistical analysis, showed  that the average flexural strength of group G1 (351.7 MPa) and group G3 (356.3 MPa) were significantly lower than those of group G2 (421.9 MPa) and group G4 (758.4 MPa); as well as all hardness averages were significantly different, being higher for group G2 (1.936,6 HV) and group G4 (1.321,4 HV), when compared to group G1 (1.173,3 HV) and group G3 (1.094,6 HV).  It was concluded that the solid state sintering proved to be more efficient to obtain maximum densification of the ceramics blocks, resulting in high values of flexural strength and hardness.

scholarly journals Flexural Strength of Composite Based Provisional Crown Materials

2021 ◽  
Vol 6 (01) ◽  
pp. 78-81
Author(s):  
Osama Qutub ◽  
Salman Khalid Bashnani ◽  
Faisal Khalid Bashnaini
Keyword(s):  
Composite Material ◽  
Flexural Strength ◽  
Treatment Time ◽  
Testing Machine ◽  
Bending Test ◽  
Computer Assisted ◽  
Three Point Bending ◽  
Long Span ◽  
Cad Cam ◽  
Group 2

Introduction: One of the important aspects of provisional restorations, especially in case of long-span edentulous situations, short-height pontics, extended treatment time and in patients with para-functional habits is their flexural strength. Maintaining the integrity of the provisional restorations throughout the course of treatments is highly valuable and important to have a predictable outcome. Objectives: To evaluate and compare the flexural strength of composite based provisional materials. Materials and Methods: Materials: Group 1, conventional bisacryl composite material (Protemp 4, 3M). Group 2, Computer Assisted Designing - Computer Assisted Milling (CAD-CAM) composite provisional material (CAD Temp). Method: Twenty identical specimens sized 25×2×2-mm were prepared from each material. A standard three-point bending test was conducted on the specimens with a universal testing machine at a 0.5 mm/min crosshead speed, and the flexural strength values were calculated (MPa) for each specimen. The flexural strength data were statistically analyzed using T-Test. Results: The measured mean flexural strength values (MPa) were as follow: group1 = 99.38 in comparison to group 2 = 92.06. There were statistically significant differences among the flexural strengths of tested materials (P < 0.05), The conventional group had significantly higher flexural strength than the CAD/CAM group (p < 0.05). Conclusion: Within the limitation of this study, the bisacryl composite resin (Protemp 4) provisional material has superior flexural strength than CAD/CAM composite material. Although many authors recommended the use of CAD/CAM provisional materials, this study prove that the material composition is as important as the material method of fabrication.

scholarly journals Resin Composite Materials for Chairside CAD/CAM Restorations: A Comparison of Selected Mechanical Properties

2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Wojciech Grzebieluch ◽  
Marcin Mikulewicz ◽  
Urszula Kaczmarek
Keyword(s):  
Mechanical Properties ◽  
Flexural Strength ◽  
Weibull Modulus ◽  
Resin Composite ◽  
Flexural Modulus ◽  
Bending Test ◽  
Weibull Analysis ◽  
Three Point Bending ◽  
Characteristic Strength ◽  
Cad Cam

Objective. The aim was to evaluate the flexural strength, flexural modulus, microhardness, Weibull modulus, and characteristic strength of six resin composite blocks (Grandio Blocs-GR, Tetric CAD-TE, Brilliant Crios-CR, Katana Avencia-AV, Cerasmart-CS, and Shofu Block HC-HC). Methods. Flexural strength and flexural modulus were measured using a three-point bending test and microhardness using the Vickers method. Weibull analysis was also performed. Results. The materials showed flexural strength ranging from 120.38 (HC) to 186.02 MPa (GR), flexural modulus from 8.26 (HC) to 16.95 GPa (GR), and microhardness from 70.85 (AV) to 140.43 (GR). Weibull modulus and characteristic strength ranged from 16.35 (CS) to 34.98 (TE) and from 123.45 MPa (HC) to 190.3 MPa (GR), respectively. Conclusions. GR, TE, and CR presented significantly higher flexural strength, modulus, Weibull modulus, and characteristic strength than the others.

scholarly journals Effect of microwave disinfection on physical and mechanical properties of acrylic resins

2008 ◽  
Vol 19 (4) ◽  
pp. 348-353 ◽  
Author(s):  
Rafael Leonardo Xediek Consant ◽  
Erica Brenoe Vieira ◽  
Marcelo Ferraz Mesquita ◽  
Wilson Batista Mendes ◽  
João Neudenir Arioli-Filho
Keyword(s):  
Flexural Strength ◽  
Room Temperature ◽  
Physical And Mechanical Properties ◽  
Hardness Test ◽  
Knoop Hardness ◽  
Microwave Energy ◽  
Bending Test ◽  
Acrylic Resins ◽  
Strength Tests ◽  
The Impact

This study evaluated the effect of microwave energy on the hardness, impact strength and flexural strength of the Clássico, Onda-Cryl and QC-20 acrylic resins. Aluminum die were embedded in metallic or plastic flasks with type III dental stone, in accordance with the traditional packing technique. A mixing powder/liquid ratio was used according to the manufacturer's instructions. After polymerization in water batch at 74ºC for 9 h, boiling water for 20 min or microwave energy at 900 W for 10 min, the specimens were deflasked after flask cooling at room temperature, and submitted to finishing. Specimens non-disinfected and disinfected by microwave irradiation were submitted to hardness, impact and flexural strength tests. Each specimen was immersed in distilled water and disinfected in a microwave oven calibrated to 650 W for 3 min. Knoop hardness test was performed with 25 g load for 10 s, impact test was carried out using the Charpy system with 40 kpcm, and 3-point bending test with a crosshead speed of 0.5 mm/min until fracture. Data were submitted to statistical analysis by ANOVA and Tukey's test (?=0.05). Disinfection by microwave energy decreased the hardness of Clássico and Onda-Cryl acrylic resins, but no effect was observed on the impact and flexural strength of all tested resins.

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

Cerâmica ◽  
2016 ◽  
Vol 62 (362) ◽  
pp. 121-127 ◽  
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.

scholarly journals Effect of Gamma Radiation and Endodontic Treatment on Mechanical Properties of Human and Bovine Root Dentin

2016 ◽  
Vol 27 (6) ◽  
pp. 670-674 ◽  
Author(s):  
Veridiana Resende Novais ◽  
Priscilla Barbosa Ferreira Soares ◽  
Carlla Martins Guimarães ◽  
Laís Rani Sales Oliveira Schliebe ◽  
Stella Sueli Lourenço Braga ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Flexural Strength ◽  
Gamma Radiation ◽  
Hardness Test ◽  
Knoop Hardness ◽  
Endodontic Treatment ◽  
Bending Test ◽  
Human Teeth ◽  
Significant Difference ◽  
Root Dentin

Abstract This study evaluated the effect of gamma radiation and endodontic treatment on the microhardness and flexural strength of human and bovine root dentin. Forty single-rooted human teeth and forty bovine incisor teeth were collected, cleaned and stored in distilled water at 4 °C. The human and bovine teeth were divided into 4 groups (n=10) resulting from the combination of two study factors: first, regarding the endodontic treatment in 2 levels: with or without endodontic treatment; and second, radiotherapy in two levels: with or without radiotherapy by 60 Gy of Co-60 gamma radiation fractioned into 2 Gy daily doses five days per week. Each tooth was longitudinally sectioned in two parts; one-half was used for the three-point bending test and the other for the Knoop hardness test (KHN). Data were analyzed by 3-way ANOVA and Tukey HSD test (α=0.05). No significant difference was found for flexural strength values. The human dentin had significantly higher KHN than the bovine. The endodontic treatment and radiotherapy resulted in significantly lower KHN irrespective of tooth origin. The results indicated that the radiotherapy had deleterious effects on the microhardness of human and bovine dentin and this effect is increased by the interaction with endodontic therapy. The endodontic treatment adds additional negative effect on the mechanical properties of radiated tooth dentin; the restorative protocols should be designed taking into account this effect.

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