scholarly journals The Role of Solvents in Lithography-Based Ceramic Manufacturing of Lithium Disilicate

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 1045
Author(s):  
Malte Hartmann ◽  
Markus Pfaffinger ◽  
Jürgen Stampfl
Keyword(s):  
Bending Strength ◽  
Lithium Disilicate ◽  
Ceramic Materials ◽  
Processing Technique ◽  
Digital Dentistry ◽  
Photo Polymerization ◽  
Complementary Approach ◽  
Dental Practices ◽  
Ceramic Manufacturing ◽  
Ceramic Restorations

Digital dentistry is increasingly replacing conventional methods of manually producing dental restorations. With regards to computer-aided manufacturing (CAM), milling is state of the art. Additive manufacturing (AM), as a complementary approach, has also found its way into dental practices and laboratories. Vat photo-polymerization is gaining increasing attention, because it enables the production of full ceramic restorations with high precision. One of the two predominantly used ceramic materials for these applications is lithium disilicate, Li2Si2O5. This glass ceramic exhibits a substantial fracture toughness, although possesses much lower bending strength, than the other predominantly used ceramic material, zirconia. Additionally, it shows a much more natural optical appearance, due to its inherent translucency, and therefore is considered for anterior tooth restorations. In this work, an optimized formulation for photo-reactive lithium disilicate suspensions, to be processed by vat photo-polymerization, is presented. Following the fundamental theoretical considerations regarding this processing technique, a variety of solvents was used to adjust the main properties of the suspension. It is shown that this solvent approach is a useful tool to effectively optimize a suspension with regards to refractive index, rheology, and debinding behavior. Additionally, by examining the effect of the absorber, the exposure time could be reduced by a factor of ten.

Influence of Ceramic Thickness and Ceramic Materials on Fracture Resistance of Posterior Partial Coverage Restorations

2015 ◽  
Vol 40 (2) ◽  
pp. 211-217 ◽  
Author(s):  
EM Bakeman ◽  
N Rego ◽  
Y Chaiyabutr ◽  
JC Kois
Keyword(s):  
Glass Ceramic ◽  
Fracture Resistance ◽  
Testing Machine ◽  
Lithium Disilicate ◽  
Ceramic Materials ◽  
Tooth Structure ◽  
Partial Coverage ◽  
Significant Difference ◽  
Ceramic Thickness ◽  
Ceramic Restorations

SUMMARY This study evaluated the influence of ceramic thickness and ceramic materials on fracture resistance of posterior partial coverage ceramic restorations. Forty extracted molars were allocated into four groups (n=10) to test for two variables: 1) the thickness of ceramic (1 mm or 2 mm) and 2) the ceramic materials (a lithium disilicate glass-ceramic [IPS e.max] or leucite-reinforced glass ceramic [IPS Empress]). All ceramic restorations were luted with resin cement (Variolink II) on the prepared teeth. These luted specimens were loaded to failure in a universal testing machine, in the compression mode, with a crosshead speed of 1.0 mm/min. The data were analyzed using two-way analysis of variance and the Tukey Honestly Significantly Different multiple comparison test (α =0.05). The fracture resistance revealed a significant effect for materials (p<0.001); however, the thickness of ceramic was not significant (p=0.074), and the interaction between the thickness of ceramic and the materials was not significant (p=0.406). Mean (standard deviation) fracture resistance values were as follows: a 2-mm thickness of a lithium disilicate bonded to tooth structure (2505 [401] N) revealed a significantly higher fracture resistance than did a 1-mm thickness of leucite-reinforced (1569 [452] N) and a 2-mm thickness of leucite-reinforced ceramic bonded to tooth structure (1716 [436] N) (p<0.05). There was no significant difference in fracture resistance values between a lithium disilicate ceramic at 1-mm thickness (2105 [567] N) and at 2-mm thickness. Using a lithium disilicate glass ceramic for partial coverage restoration significantly improved fracture resistance compared to using a leucite-reinforced glass ceramic. The thickness of ceramic had no significant effect on fracture resistance when the ceramics were bonded to the underlying tooth structure.

Manufacturing Reliable Ceramic Crowns: The Role of Abrasive Machining in Digital Dentistry

2016 ◽  
Author(s):  
Ling Yin ◽  
Abdur-Rasheed Alao ◽  
Xiao-Fei Song ◽  
Richard Stoll
Keyword(s):  
Digital Processing ◽  
Ceramic Materials ◽  
Current Status ◽  
Abrasive Machining ◽  
Digital Dentistry ◽  
Dental Ceramic ◽  
Dental Restorations ◽  
Cad Cam ◽  
Ceramic Restorations

Dental caries is a ubiquitous disease and nearly 100% of the population is affected worldwide. Consequently, reliable dental restorations are in high demand. More and more patients expect and request esthetics and biosafety, and desire metal-free prostheses. Both biocompatible and esthetic ceramics and digital processing of prostheses have been developed to meet these demands. This paper reviews the current status of abrasive machining involved in affordable digital dental ceramic restorations with regard to dental ceramic materials, dental CAD/CAM systems, and extra/intraoral dental handpiece adjustments. It highlights the importance and challenge of abrasive machining technologies in manufacturing of affordable and reliable dental restorations with cutting-edge materials.

Ceramic Materials. Effects of Fracture Origin and Microstructure on Bending Strength of High-Strength Si3N4.

1994 ◽  
Vol 43 (489) ◽  
pp. 599-605 ◽  
Author(s):  
Akira YAMAKAWA ◽  
Takehisa YAMAMOTO ◽  
Tomoyuki AWAZU ◽  
Kenji MATSUNUMA ◽  
Takao NISHIOKA
Keyword(s):  
Bending Strength ◽  
High Strength ◽  
Ceramic Materials ◽  
Fracture Origin

Characteristics of Low Temperature Degradation Free ZTA for Artificial Joint

2014 ◽  
Vol 631 ◽  
pp. 18-22 ◽  
Author(s):  
Junji Ikeda ◽  
Takayuki Murakami ◽  
Takayoshi Shimozono ◽  
Reiji Watanabe ◽  
Mikio Iwamoto ◽  
...  
Keyword(s):  
Low Temperature ◽  
Phase Stability ◽  
Mechanical Characteristics ◽  
Bending Strength ◽  
Accelerated Aging ◽  
Ceramic Materials ◽  
Wear Property ◽  
Artificial Joint ◽  
Four Point Bending ◽  
Bearing Materials

Low temperature degradation free Zirconia toughened alumina (ZTA) has been developed. It is reported that ZTA has higher mechanical strength compared to alumina due to the stress induced transformation and spontaneously transformation of zirconia phase on some ZTA have been occurred. For achieving the higher reliability of artificial joint prosthesis alternative to alumina and other ceramic materials, it is necessary to improve and validate the both mechanical characteristics and phase stability at the same time. We evaluated that microstructure, mechanical characteristics and phase stability of newly developed ZTA (BIOCERAM®AZUL). It was confirmed that four-point bending strength and weibull modulus were extreamly high, and ZTA has higher reliability. There were no significant changes and deterioration in four-point bending strength, crystal structure and wear property with and without accelerated aging test. Newly developed ZTA not only with high mechanical characteristics but also with phase stability could be quite useful as bearing materials in artificial joints for longer clinical use.

Effects of TiN Content on Mechanical Properties and Microstructure of ATN Materials

2013 ◽  
Vol 589-590 ◽  
pp. 590-593 ◽  
Author(s):  
Min Wang ◽  
Jun Zhao
Keyword(s):  
Mechanical Properties ◽  
Mechanical Property ◽  
Fracture Toughness ◽  
Vickers Hardness ◽  
Bending Strength ◽  
Sintering Temperature ◽  
Ceramic Materials ◽  
Hot Press ◽  
Hot Press Sintering ◽  
Tin Content

In order to investigate the effects of TiN content on Al2O3/TiN ceramic material (ATN), the ATN ceramic materials were prepared of TiN content in 30%, 40%, 50%, 60% in the condition of hot press sintering. The sintering temperature is 1700°C, the sintering press is 32MPa, and the holding time are 5min, 10min, 15min. The effects of TiN content on mechanical properties and microstructure of ATN ceramic materials were investigated by analyzing the bending strength, hardness, fracture toughness. The results show that ATN50 has the best mechanical property, its bending strength is 659.41MPa, vickers hardness is 13.79GPa, fracture toughness is 7.06MPa·m1/2. It is indicated that the TiN content has important effect on microstructure and mechanical properties of ATN ceramic materials.

Lithography-Based Ceramic Manufacturing (LCM) for Dental Applications

2018 ◽  
Vol 939 ◽  
pp. 95-103 ◽  
Author(s):  
Malte Hartmann ◽  
Markus Pfaffinger ◽  
Jürgen Stampfl
Keyword(s):  
Light Exposure ◽  
Biaxial Bending ◽  
Bending Tests ◽  
Manufacturing Method ◽  
Processing Step ◽  
Complex Procedure ◽  
Ceramic Manufacturing ◽  
Dental Applications ◽  
Ceramic Restorations

Dental applications like crowns, veneers or bridges require high accuracy to be fitted on the patient’s stump. Stereolithography is an additive manufacturing method, which offers high precision by using light exposure as the layer generating mechanism. In the LCM process, this precision is combined with a thermal post-processing step to achieve full ceramic restorations. The overall production of such ceramic parts in a reproducible way is a highly complex procedure. The first requirement is to find a slurry formulation, which is stable against sedimentation and segregation, that is also processable in a stereolithographic system. Such a formulation has been found by us, which could be shown by rheology measurements. During experiments with this formulation, it could be observed that there is a correlation between wet film thickness and resolution. Several adjustments to the machine have been made, to fully control this parameter. Namely, changes to the vat, the doctor blade and the building platform have been made. The improvement of the process and the quality of the final parts are validated by fabricating Siemens stars and by biaxial bending tests.

Joining of Ceramic Components in the Green State via LPIM

2007 ◽  
Vol 29-30 ◽  
pp. 207-210 ◽  
Author(s):  
Rolf Waesche ◽  
Carl Paulick ◽  
Gabriele Steinborn ◽  
V. Richter ◽  
M. Werner
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Bending Strength ◽  
Ceramic Materials ◽  
Alumina Powder ◽  
Second Phase ◽  
Green State ◽  
Ceramic Components ◽  
Molded Parts

It has been successfully demonstrated that ceramic materials can be joined in the green state without a second phase by using low pressure injection molded parts. The investigation of the joining interface revealed that a high quality interface can be achieved by carefully adjusting the different manufacturing steps. The use of monomodal particle size distribution in the used powder CT3000SG is inferior to a broader particle size distribution obtained by replacing 33% of the finer alumina powder by coarser CT1200SG. In this way the dewaxing process is significantly improved when the wall thickness of the part exceeds 3 mm. The investigation of the mechanical properties of the joined and sintered parts revealed, that the bending strength of the joined specimens achieved about 80 % of the unjoined, monolithic specimens.

scholarly journals Mechanical properties of microwave sintered Si3N4-based ceramics

2002 ◽  
Vol 34 (3) ◽  
pp. 223-229 ◽  
Author(s):  
O.I. Getman ◽  
V.V. Holoptsev ◽  
V.V. Panichkina ◽  
I.V. Plotnikov ◽  
V.K. Soolshenko
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Bending Strength ◽  
Normal Pressure ◽  
Ceramic Materials ◽  
Particle Sizes ◽  
Phase Measurements ◽  
Ceramic Samples ◽  
Mean Size ◽  
The Mean

The mechanical properties and microstructure formation processes in Si3N4+3% AI2O3+5% Y2O3(Yb2O3) ceramic compacts sintered under microwave heating (MWH) and under traditional heating (TH) were investigated. The initial ceramic materials were powder blends of silicon nitride with oxides. The mean powder particle sizes were 0.5-1.0 mim. The content of alfa-phase in the Si3N4 powder was more than 95 %. The samples were sintered at 1800BC in nitrogen at normal pressure, the heating rate in all experiments was 60BC/min. The Vickers hardness (HV), fracture toughness (K1C) and bending strength (on) were determined. The microstructures of fracture surfaces of samples were studied by SEM. Quantitative microstructure analysis was carried out. It was shown that the values of HV and Kic of ceramic samples sintered under MWH at 1800BC rose steadily with the sintering time. This caused an increase in density, which reached maximum as fast as after 30 min of the MWH sintering; the mass loss at that time amounted to 3-4 %. The porosity of sintered samples with an addition of yttria was less than 1 %, that of ytterbia was greater, 2.4 %. For similar values of relative density, the hardness and fracture toughness of ceramic samples produced under MWH were higher as compared with those of samples sintered under TH. The microstructure of samples had the form of elongated grains in a matrix of polyhedral grains of the beta-Si3N4 phase. Measurements showed the mean size of grains in samples produced by MWH to be greater that in samples produced by TH. A larger number of elongated grains were formed. It was concluded that for sintering under MWH of Si3N4-based ceramics the growth of elongated beta-Si3N4 grains and formation of a "reinforced" microstructure were promoted and thereby improved the mechanical properties of such ceramics.

Step-stress vs. staircase fatigue tests to evaluate the effect of intaglio adjustment on the fatigue behavior of simplified lithium disilicate glass-ceramic restorations

2021 ◽  
Vol 113 ◽  
pp. 104091
Author(s):  
Andressa Borin Venturini ◽  
Thaís Camponogara Bohrer ◽  
Patrícia Eliana Fontana ◽  
Tatiana Tambara Fröhlich ◽  
Liliana Gressler May ◽  
...  
Keyword(s):  
Glass Ceramic ◽  
Fatigue Behavior ◽  
Lithium Disilicate ◽  
Fatigue Tests ◽  
Ceramic Restorations

Environmental Friendly Ceramic Building Materials

2016 ◽  
Vol 690 ◽  
pp. 150-155 ◽  
Author(s):  
Toyohiko Sugiyama ◽  
Keiji Kusumoto ◽  
Masayoshi Ohashi ◽  
Akinori Kamiya
Keyword(s):  
High Performance ◽  
Building Materials ◽  
Bending Strength ◽  
Low Cost ◽  
Porous Ceramic ◽  
Ceramic Materials ◽  
Porous Ceramics ◽  
Heat Island ◽  
Solar Reflectance ◽  
Ceramic Building

The global warming is one of the most serious problems. The decrease of CO2 emissions in our daily life is an important subject today. Recently, an application of water retentive materials as a paving material has attracted a great deal of attention in Japan. This material is effective for reducing heat island phenomenon, which is also a recent problem in many cities in Japan. Water retained in the material during rainfall evaporates when heated by sunshine. The latent heat absorbed by evaporating water works to cool the surroundings. The water retentive ceramic products are expected to be useful for building materials as well as pavements. Several performances are required on the water retentive ceramics when it is used as building materials. Its cost and quality are the important factors. Porous ceramic materials formed by pressing without firing is one of ideal low cost and eco-friendly candidates. The porous ceramics is also expected to be produced from recycled ceramic materials. By optimizing its composition and forming method, a water retentive material with high performance was developed. The trial product had the properties as follows; fracture toughness: 1300N, bending strength: 175N/cm, water absorption: larger than 30%, and precision in size (length): +-0.5mm for 150mm. The product showed also enough frost resistance. In this paper, the fundamental properties of the porous ceramics prepared without firing are discussed with referring to the results of the field experiments.Another subject recently studied by several tile manufactures in Japan is the glazed tile with high solar reflectance. The exterior walls covered with such a high solar reflectance tile keeps the surface temperature of the wall lower under the strong sunshine of summer. It is effective against heat-island phenomenon. In this paper, the outline of the research results on visible and infrared reflectance of many kinds of glazes is also discussed.

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