Flexural Strength of In-Ceram Alumina and In-Ceram Zirconia Core Materials
The study compared the flexural strength of In-Ceram alumina and In-Ceram zirconia systems. The probability of failure of the two glass-infiltrated ceramic core materials was analyzed with and without lamination with Vitadur-alpha porcelain.
Ten uniform beams of core materials as well as 10 beams of laminated core materials were fabricated for In-Ceram alumina and In-Ceram zirconia. The samples were subjected to three-point bending tests. Flexural strength for both ceramic core materials was determined with and without their porcelain laminations. The strength data were analyzed using the Weibull method. Modes of failure for both systems were determined using scanning electron micrography.
The strength of the In-Ceram zirconia system was significantly higher than In-Ceram alumina when comparing their core materials with and without porcelain lamination. The failure mode for both systems was predominantly transgranular fracture of alumina platelets.
In-Ceram zirconia demonstrated higher flexural strength than In-Ceram alumina.
Available from: Elie Daou
- "Authors agreed that Y-TZP can withstand physiologic functional loading forces and are comparable to metal-ceramic FPDs  . Strength and marginal fit of zirconia ceramic has been confirmed by extensive laboratory testing  . Still 5 to 10 year clinical studies are needed to determine primary mode of failure and success rate  "
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ABSTRACT: Metal ceramic restorations were considered the gold standard as reliable materials. Increasing demand for esthetics
supported the commercialization of new metal free restorations. A growing demand is rising for zirconia prostheses.
Peer-reviewed articles published till July 2013 were identified through a Medline (Pubmed and Elsevier). Emphasizing
was made on zirconia properties and applications. Zirconia materials are able to withstand posterior physiologic loads.
Although zirconia cores are considered as reliable materials, these restorations are not problem free.
Available from: pmr.lf1.cuni.cz
- "To date sufficient data is lacking on changes in the strength that occur during aging of the material. Given the flexural strength values of yttrium-stabilized zirconia, the manufacturers anticipate that the materials will comply with the flexural strength requirements of ISO 6872 even after a decrease in strength (Ryge and Cvar, 1971; Chong et al., 2002). The zirconia cores are supplied in colour and therefore have a good balance between translucency and opacity, which means that the core is not excessively transparent despite transmitting light, yet manages to mask dark coloured substrates. "
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ABSTRACT: The objective of the study was to evaluate the clinical outcomes of all-ceramic crowns three years after placement of the restoration in the oral cavity. The aim of the present clinical study were surveyed the Procera®, Cercon® and LAVA™ systems. In total, 121 crowns were followed in 33 patients (7 men and 26 women) with an average age of 53.5 years. The eighty crowns were placed in anterior and forty one crowns in posterior teeth. The crowns were fabricated in two dental laboratories and delivered in two private dental practices. The clinical trial was conducted according to American Dental Association guidelines. The patients were requested to provide their consent to the regular clinical examination including radiographic and photographic records. A total of 102 crowns were made of zirconium oxide ceramic cores - 58 Cercon®; 43 LAVA™, while 19 crowns were made of aluminum oxide cores Procera®. The veneering ceramic LAVA™ Ceram was used. The success rate was analyzed using Kaplan-Meier statistics and, in our case, the overall three-year success rate reached 96.7%. All-ceramic crowns with polycrystalline ceramic cores have low susceptibility to fracture, in this study just 3.3%.
Available from: Marianna E Grigoriadou
- "The high strength of In - Ceram Zirconia is attributed to the phase transformation toughening mechanism that takes place in the mass of the material ( McLaren and White 1999 ; Chong et al . 2002 ) , which is described later ."
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ABSTRACT: In this study, the fracture resistance of three-unit posterior fixed partial dentures, with frameworks fabricated from three different zirconium dioxide materials, before and after exposure to the artificial oral environment, was compared.
Forty-eight human mandibular premolars and forty-eight human mandibular molars were used as abutments for 48 posterior three-unit all-ceramic FPDs. The teeth were randomly divided into three test groups of 16 samples each. All teeth were prepared with a 6° convergence angle and a 1.2mm deep chamfer. DC-Zirkon® was used for the fabrication of the frameworks for the first test group with the DCS-Precident® system, while Procera® Zirconia was used for the fabrication of the frameworks for the second group with Procera® system and VITA In-Ceram® 2000 YZ Cubes were used for the fabrication of frameworks for the third group with Cerec®InLab system. All frameworks were veneered with VITA VM®9 veneering porcelain. Half of the specimens of each group were loaded in an artificial mouth for 1.2 million cycles to simulate 5 years of clinical function. No fracture occurred during artificial aging. Then, all samples were subjected to the fracture strength test in a universal-testing machine. The median values of fracture strength in (N) before and after loading in the artificial mouth were as follows: 2131 and 1797, 1684 and 1394, 1845 and 1625N for the DC-Zirkon, the Procera Zirconia FPDs and the YZ Cubes, respectively.
All three types of zirconium dioxide bridges have the potential to withstand physiological occlusal forces applied in the posterior region and can be therefore interesting alternatives to replace PFM fixed partial dentures. The connector shape and size, veneering ceramic, aging behavior and long-term clinical performance need to be further assessed before recommending Y-TZP all-ceramic FPDs for daily practice.
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