Influence of Sintering Holding Time on Flexural Strength of Dental CAD/CAM Zirconia

2016 ◽  
Vol 43 (2) ◽  
pp. 185-192 ◽  
Author(s):  
Byung-Wook Jeon ◽  
Gwang-Young Lee
Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1745
Author(s):  
Tamaki Hada ◽  
Manabu Kanazawa ◽  
Maiko Iwaki ◽  
Awutsadaporn Katheng ◽  
Shunsuke Minakuchi

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.


2017 ◽  
Vol 33 (1) ◽  
pp. 99-109 ◽  
Author(s):  
Michael Wendler ◽  
Renan Belli ◽  
Anselm Petschelt ◽  
Daniel Mevec ◽  
Walter Harrer ◽  
...  

2020 ◽  
Vol 124 (6) ◽  
pp. 800.e1-800.e7
Author(s):  
Gülce Çakmak ◽  
Hakan Yilmaz ◽  
Özge Aydoğ ◽  
Burak Yilmaz

Cerâmica ◽  
2016 ◽  
Vol 62 (362) ◽  
pp. 121-127 ◽  
Author(s):  
P. P. Kist ◽  
I. L. Aurélio ◽  
M. Amaral ◽  
L. G. May

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.


2018 ◽  
Vol 34 ◽  
pp. e9
Author(s):  
M.A. Basílio ◽  
E. Lima ◽  
A.B. Soares ◽  
P.F. Cesar

2020 ◽  
Vol 34 (12) ◽  
pp. 1253-1268
Author(s):  
João Paulo Mendes Tribst ◽  
Amanda Maria de Oliveira Dal Piva ◽  
Gabriel Cirone Lopes ◽  
Alexandre Luiz Souto Borges ◽  
Marco Antonio Bottino ◽  
...  

2019 ◽  
Vol 45 (8) ◽  
pp. 10250-10259
Author(s):  
Claudinei dos Santos ◽  
Bruno Galvão Simba ◽  
Ronaldo Reis Silva ◽  
Manuel Fellipe Rodrigues Pais Alves ◽  
Roberto Oliveira Magnago ◽  
...  

2007 ◽  
Vol 336-338 ◽  
pp. 1587-1589
Author(s):  
Wen Xu Li ◽  
Hua Zhao ◽  
Ying Song ◽  
Bin Su ◽  
Fu Ping Wang

Ca3(PO4)2/ZrO2 dental composite ceramics using for CAD/CAM system were prepared and the effects of weak phases on microstructures and mechanical properties were studied. The results showed that intergranular spreads happened with the increasing Ca3(PO4)2 contents due to the discontinuity of weak interfaces between Zirconia and Calcium phosphate in matrix. So the flexural strength and hardness of the Ca3(PO4)2/ZrO2 composite ceramics were decreased effectively, which improved the machinability of the composites. On the other hand, strong interfaces between Zirconias increased the integrality of the ceramic structures. ZrO2 composite Ceramics with 15% Ca3(PO4)2 were sintered at 1350°C. The flexural strength is 300.44MPa, fracture toughness is 4.36 MPam1/2, and hardness is 6.69 GPa. The cutting exponent of the Ca3(PO4)2/ZrO2 composite ceramics is obviously lower than that of the common commercial Vita Mark II and Dicor MGC ceramics, which shows good mechanical properties and machinability.


2017 ◽  
Vol 37 (4) ◽  
pp. 323-334 ◽  
Author(s):  
Shuai Li ◽  
Guoqun Zhao ◽  
Jiachang Wang

Abstract Gas counter pressure (GCP) technology can impose a reverse pressure to melt and thereby effectively increase the pressure acting on the melt at flow front. Theoretically, it has a potential to solve some defects often occurring in conventional injection molding (CIM) process. This paper designed and manufactured a GCP injection mold. GCP injection molding experiments were conducted. Effects of GCP process on melt flow and density, dimensional accuracy, and mechanical properties of molded samples were investigated. The results showed that GCP process can effectively inhibit the “fountain effect” in melt filling process, decrease the dimensional shrinkage of molded samples, increase dimensional accuracy of samples, and effectively improve impact property of samples. For the samples without weld line, tensile strength and flexural strength of GCP injection molded samples are slightly increased in comparison with those of CIM samples, but for the samples with weld line, GCP process can greatly improve the tensile strength and flexural strength of molded samples. When GCP is 9 MPa and GCP holding time is 10 s, the dimensional accuracy of molded samples without weld line, the tensile strength and flexural strength of the molded samples with weld line all increase up to maximum values. In comparison with CIM samples, the dimensional shrinkage of samples without weld line decreases by 17.2%, the tensile strength and flexural strength of samples with weld line increase by 30.51% and 23.69%, respectively. The impact value of the samples molded by process parameter combination of GCP 9 MPa and GCP holding time 20 s is the highest, and the impact value increases by 18.65%.


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