Type of Failure of Zirconia-Based Ceramics in Dental Laboratory in Misurata, Libya

2014 ◽  
Vol 575 ◽  
pp. 22-25
Author(s):  
Mohamed M. Aboras ◽  
A. Muchtar ◽  
C.H. Azhari ◽  
N. Yahaya

Zirconia (ZrO2) is used to fix restorations as a core material because of its mechanical properties, aesthetics, and compatibility. This study aims to analyze the failure types in ZrO2-based restoration fabricated in a dental laboratory in Misurata, Libya. Data were collected from laboratory records for a 30-day period with follow-up for five months. About 6% of the total restorations had defects with different percentages, 46% of which were fractures, 29% of which had weak bonding between ZrO2frameworks and veneers, 18% of which had cracks, and 7% of which had shade defects. Although ZrO2is a suitable material for dental restorations, defects may occur and lead to the failure of dental restorations. A thorough study is necessary to analyze the cause of failurein zirconia-based restorationsand to improve the properties to produce a versatile dental restorative material.

2014 ◽  
Vol 606 ◽  
pp. 85-88
Author(s):  
Mohamed M. Aboras ◽  
Kai Yuan Theng ◽  
Andanastuti Muchtar ◽  
Che Husna Azhari ◽  
Norziha Yahaya

The use of tetragonal zirconia as a dental restorative material has recently increased because of its unique mechanical and optical properties, as well as high biological compatibility with the oral cavity environment. However, the mechanical properties of zirconia can be severely degraded, which leads to the failure of dental restorations. This review focuses on the low-temperature degradation of dental zirconia and its effects on the properties of zirconia and on the oral environment. The purpose is to show the importance of this negative phenomenon and suggest guidelines for minimizing the aging of zirconia that is used as a dental restoration material.


2018 ◽  
Vol 21 (1) ◽  
pp. 126
Author(s):  
Rafael Menezes Silva ◽  
Letícia Pena Botelho ◽  
Adriana Maria Botelho ◽  
Karine Taís Aguiar Tavano

<p>Biological restorations, involving a technique of uniting autogenous or homogenous dental fragment for use as the primary restorative material, are an alternative for morphological and functional re-establishment of teeth with extensive coronal destruction.   Despite the wide range of restorative materials available in dentistry, no material has proved to be as efficient as the natural tooth structure. This article illustrates a therapeutic option for rehabilitating a devitalized mandibular tooth with a weakened coronal remainder by using the biological restoration technique. The authors present the sequence of planning and performing the technique, such as the characteristics of preparation of the tooth and fragment, impression taking, cutting and cementation of the fragment, and the  four-year follow-up of the biological restoration, which  shows the success of the technique with marginal adaptation and satisfactory esthetic appearance.</p><p> </p><p><strong>Keywords</strong></p><p>Adhesive; Devitalized tooth; Permanent dental restorations.</p>


2003 ◽  
Vol 14 (12) ◽  
pp. 1033-1037 ◽  
Author(s):  
J. Loof ◽  
H. Engqvist ◽  
N.-O. Ahnfelt ◽  
K. Lindqvist ◽  
L. Hermansson

2013 ◽  
Vol 591 ◽  
pp. 150-153 ◽  
Author(s):  
Zhao Qiang Meng ◽  
Dan Yu Jiang

Mechanical properties of dental materials are increasingly studied via nanoindentation testing. Due to the excellent mechanical properties, 3-mol%-Yttria-Stabilized Tetragonal Zirconia (3Y-TZP) has become an attractive high-toughness core material for fixed dental restorations. In this paper, the mechanical properties of 3Y-TZP were studied by nanoindentation. The continuous stiffness measurement (CSM) and the single load/unload cycle test controlled by displacement and load respectively were performed with a Berkovich indenter.


Polymers ◽  
2021 ◽  
Vol 13 (17) ◽  
pp. 2975
Author(s):  
Xinyuan Zhang ◽  
Qi Zhang ◽  
Xin Meng ◽  
Yuting Ye ◽  
Daoshuo Feng ◽  
...  

Resin-based materials have been prevalent for dental restorations over the past few decades and have been widely used for a variety of direct and indirect procedures. Typically, resin-based dental materials are required to be flowable or moldable before setting and can provide adequate mechanical strength after setting. The setting method may include, but is not limited to, light-curing, self-curing or heating. In this review, based on different indications of resin-based dental materials (e.g., dental filling composite, dental bonding agent, resin luting cement), their rheological and mechanical properties were reviewed. Viscous and flexible properties were focused on for materials before setting, while elastic properties and mechanical strength were focused on for materials after setting. At the same time, the factors that may affect their rheological and mechanical properties were discussed. It is anticipated that the insightful information and prospections of this study will be useful to the future development and fabrication of resin-based dental restorative materials.


2003 ◽  
Vol 254-256 ◽  
pp. 197-200
Author(s):  
Jesper Lööf ◽  
Hakan Engqvist ◽  
Gunilla Gómez-Ortega ◽  
Nils Otto Ahnfelt ◽  
Leif Hermansson

Membranes ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 26
Author(s):  
Sara Metwally ◽  
Daniel P. Ura ◽  
Zuzanna J. Krysiak ◽  
Łukasz Kaniuk ◽  
Piotr K. Szewczyk ◽  
...  

Atopic dermatitis (AD) is a chronic, inflammatory skin condition, caused by wide genetic, environmental, or immunologic factors. AD is very common in children but can occur at any age. The lack of long-term treatments forces the development of new strategies for skin regeneration. Polycaprolactone (PCL) is a well-developed, tissue-compatible biomaterial showing also good mechanical properties. In our study, we designed the electrospun PCL patches with controlled architecture and topography for long-term release in time. Hemp oil shows anti-inflammatory and antibacterial properties, increasing also the skin moisture without clogging the pores. It can be used as an alternative cure for patients that do not respond to traditional treatments. In the study, we tested the mechanical properties of PCL fibers, and the hemp oil spreading together with the release in time measured on skin model and human skin. The PCL membranes are suitable material as patches or bandages, characterized by good mechanical properties and high permeability. Importantly, PCL patches showed release of hemp oil up to 55% within 6 h, increasing also the skin moisture up to 25%. Our results confirmed that electrospun PCL patches are great material as oil carriers indicating a high potential to be used as skin patches for AD skin treatment.


2011 ◽  
Vol 70 ◽  
pp. 405-409 ◽  
Author(s):  
Emrah Demirci ◽  
Memiş Acar ◽  
Behnam Pourdeyhimi ◽  
Vadim V. Silberschmidt

Having a unique microstructure, nonwoven fabrics possess distinct mechanical properties, dissimilar to those of woven fabrics and composites. This paper aims to introduce a methodology for simulating a dynamic response of core/sheath-type thermally bonded bicomponent fibre nonwovens. The simulated nonwoven fabric is treated as an assembly of two regions with distinct mechanical properties. One region - the fibre matrix – is composed of non-uniformly oriented core/sheath fibres acting as link between bond points. Non-uniform orientation of individual fibres is introduced into the model in terms of the orientation distribution function in order to calculate the structure’s anisotropy. Another region – bond points – is treated in simulations as a deformable bicomponent composite material, composed of the sheath material as its matrix and the core material as reinforcing fibres with random orientations. Time-dependent anisotropic mechanical properties of these regions are assessed based on fibre characteristics and manufacturing parameters such as the planar density, core/sheath ratio, fibre diameter etc. Having distinct anisotropic mechanical properties for two regions, dynamic response of the fabric is modelled in the finite element software with shell elements with thicknesses identical to those of the bond points and fibre matrix.


2003 ◽  
Vol 11 (3) ◽  
pp. 162-167 ◽  
Author(s):  
Linda Wang ◽  
Paulo Henrique Perlatti D'Alpino ◽  
Lawrence Gonzaga Lopes ◽  
José Carlos Pereira

A wide variety of dental products that are launched on the market becomes the correct selection of these materials a difficult task. Although the mechanical properties do not necessarily represent their actual clinical performance, they are used to guide the effects of changes in their composition or processing on these properties. Also, these tests might help somehow the clinician to choose once comparisons between former formulations and new ones, as well as, with the leading brand, are highlighted by manufactures. This paper presents a review of the most important laboratory tests. In this manner, the knowledge of these tests will provide a critical opinion related to the properties of different dental materials.


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