Fracture strength of machined ceramic crowns as a function of tooth preparation design and the elastic modulus of the cement

Clinical Relevance When restoring teeth, a higher restoring success rate can be achieved by using posts with an elastic modulus similar to that of dentin and a core, with equal or higher strength, such as glass fiber posts. Moreover, the failure mode for these post systems will allow for further repair.

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Fracture toughness of zirconia ceramic crowns made by feather-edge tooth preparation design

Vojnosanitetski pregled ◽

10.2298/vsp100820004m ◽

2012 ◽

Vol 69 (7) ◽

pp. 562-568 ◽

Cited By ~ 1

Author(s):

Nemanja Mirkovic ◽

Aleksandra Spadijer-Gostovic ◽

Zoran Lazic ◽

Branka Trifkovic

Keyword(s):

Fracture Toughness ◽

Testing Machine ◽

High Fracture Toughness ◽

Zirconia Ceramic ◽

Ceramic Samples ◽

Edge Group ◽

Group I ◽

Ceramic Crowns ◽

Tooth Preparation ◽

Edge Preparation

Background/Aim. Fracture toughness determines functional crown strenght and prevents damages on ceramics during mastication. There is a lack of relevant literature data about fracture toughness of crowns made by feather-edge preparation. Mechanical testing of ceramic samples is supposed to show if feather-edge tooth preparation is a successful method for making ceramic crowns without any risk of reduction of their mechanical properties. This research was done to establish effects of feather-edge tooth preparation on fracture toughness of single zirconia ceramic crowns. Methods. The research was performed as an experimental study. Sixty (60) ceramic crowns were made on non-carious extracted human premolars. Thirty (30) crowns were made on the basis of feather-edge preparation (experimental group I). The group II included 30 crowns made on 1 mm rounded shoulder. Crowns fabrication was executed on a copy mill production system ?Zirkonzahn? (Zirkonzahn GMBH, Gais, Germany). The spherical compression test was used to determine fracture toughness, using 6 mm diameter ceramic ball. Fracture load for damaging ceramic crown was recorded on a universal testing machine - Zwick, type 1464, with the speed of 0.05 mm/min. Results. The results of this research introduced significant differences between fracture toughness of ceramic samples in every examined group. However, fracture toughness of crowns from both group was above 2 000 N, what was double beyond a recommended value. The mean value of fracture toughness in the feather-edge group was 2 090 N, and in shoulder group it was 2 214 N. Conclusion. This research showed a high fracture toughness of zirconia crowns made on feather-edge preparation. The examined crowns showed a fracture resistance at a sufficient distance in relation to the minimum values of functional loads. Further research of functional loads of these crown is necessary, as well as research of marginal adaptation of cemented crowns and gingival inflammatory response.

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Ceramic Fragments and Metal-free Full Crowns: A Conservative Esthetic Option for Closing Diastemas and Rehabilitating Smiles

Operative Dentistry ◽

10.2341/12-225-t ◽

2013 ◽

Vol 38 (6) ◽

pp. 567-571 ◽

Cited By ~ 13

Author(s):

ME Miranda ◽

KA Olivieri ◽

FJ Rigolin ◽

RT Basting

Keyword(s):

Computer Aided Design ◽

Color Stability ◽

Dental Ceramics ◽

Metal Free ◽

Anterior Teeth ◽

Computer Aided ◽

Adhesive Cementation ◽

Ceramic Crowns ◽

Tooth Preparation ◽

Aided Design

SUMMARY Dental ceramics make it possible to restore anterior teeth that have been esthetically compromised, presenting a high resistance to wear, biocompatibility, color stability, and low thermal conductivity. The development of different types of ceramic and techniques for adhesive cementation have made it possible to produce more conservative restorations without involving the healthy dental structure and with minimally invasive preparation, such as the bonding of ceramic fragments. The purpose of this article is to describe a clinical case in which diastemas were closed by using nanofluorapatite ceramic (e.max Ceram, Ivoclar-Vivadent) fragments on teeth 7 and 10 with minimal tooth preparation and metal-free ceramic crowns (e-max Ceram) reinforced with zirconia copings through a computer-aided design/computer-aided manufacturing system (Lava, 3M-ESPE) on teeth 8 and 9.

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Fracture Strength of Implant-Supported Ceramic Crowns with Customized Zirconia Abutments: Screw Retained vs. Cement Retained

Journal of Prosthodontics ◽

10.1111/jopr.12278 ◽

2015 ◽

Vol 25 (1) ◽

pp. 49-53 ◽

Cited By ~ 6

Author(s):

Lorenna Bastos Lima Verde Nogueira ◽

Carmem Dolores Vilarinho Soares Moura ◽

Carlos Eduardo Francischone ◽

Valdimar Silva Valente ◽

Suyá Moura Mendes Alencar ◽

...

Keyword(s):

Fracture Strength ◽

Ceramic Crowns

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Elasticity and fracture in particulate composites with strong and degraded interfaces

Journal of Materials Research ◽

10.1557/jmr.1996.0164 ◽

1996 ◽

Vol 11 (5) ◽

pp. 1293-1304 ◽

Cited By ~ 16

Author(s):

A. Lekatou ◽

S. E. Faidi ◽

S. B. Lyon ◽

R. C. Newman

Keyword(s):

Elastic Modulus ◽

Fracture Strength ◽

Porous Polymer ◽

Glass Content ◽

Particulate Composites ◽

Nominal Strain Rate ◽

Interface Damage ◽

Small Peak ◽

Deformation And Fracture ◽

Osmotic Water

Silane-coated glass microspheres randomly embedded in an epoxy polymer matrix have been employed as a model system to investigate the degradation of disordered composite materials by water, and to test various models of deformation and fracture. Numerous composites containing sodalime (A) glass in the range 0 to 25% by volume were tested dry and immersed in saturated NaCl at 40 °C for periods up to 70 days before testing. Enhanced osmotic water uptake due to percolating interface damage was observed for composites containing more than 15% glass. The electrical resistance of similar composites filled with conducting spheres confirmed the existence of a percolation transition, though with high resistance values implying no direct contact of the spheres. Tensile measurements conducted on dry material at a nominal strain rate of about 10−3 s−1 showed an increase in elastic modulus and a decrease in the fracture strength with increasing glass content. New detail was apparent in these curves and confirmed by statistical analyses. For wet specimens, in addition to a general embrittlement effect of water absorption, there was a distinct plateau or small peak in fracture strength in the range 9 to 12% glass, and an abrupt drop between 12 and 15%. The plateau can be related to favorable crack interaction effects between disconnected clusters of interfaces just below the percolation threshold. The steep increase in elastic modulus with glass content seen in the dry material vanished entirely in wet material, which behaved like a porous polymer above 6% glass, owing to osmotic interface damage within particle clusters.

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