Fracture toughness of three heat pressed ceramic systems
Braz. j. oral sci
;
17: e18017, 2018. ilus
Article
Dans Anglais
| LILACS, BBO
| ID: biblio-906093
ABSTRACT
Aim:
The aim of this study was to evaluate fracture toughness by indentation method of three dental ceramics processed by heat pressing. The ceramics evaluated were fluorapatite glass ceramic (ZIR), glass ceramic containing leucite (POM) and leucite-reinforced glass ceramic (EMP). Materials andmethods:
Ninety disks (13mm of diameter x 4mm of thickness) and nine rectangular specimens (25x4x2mm) were made to evaluate, respectively, microhardness/fracture toughness (n=30) and elastic modulus (n=3). Samples were obtained by pressing ceramic into refractory molds. After polishing, Vickers microhardness was evaluated under 4,904N load for 20s. Elastic modulus was measured by impulse excitation technique. Data from microhardness and elastic modulus were used to calculate fracture toughness, after measuring crack length under 19,6N load applied for 20s. Results were evaluated by ANOVA and Tukey´s test.Results:
Microhardness (VHN) of POM (637.9±53.6) was statistically greater (p<0.05) than ZIR (593.0±14.3), followed by EMP (519.1±21.5); no significant difference (p=0.206) was noted for elastic modulus (GPa) (ZIR 71.5±9.0; POM 67.3±4.4; EMP 61.7±2.3). Fracture toughness (MPa/m) of POM (0.873±0.066) was statistically lower (p<0.05) than ZIR (0.977±0.021) and EMP (0.965±0.035).Conclusion:
The results suggest that fluorapatite glass ceramic (ZIR) and leucite-reinforced glass ceramic (EMP) processed by heat pressing presented greater fracture toughness, improving clinical prognosis of metal free restorations
Texte intégral:
Disponible
Indice:
LILAS (Amériques)
Sujet Principal:
Porcelaine dentaire
/
Module d'élasticité
/
Essais de dureté
langue:
Anglais
Texte intégral:
Braz. j. oral sci
Thème du journal:
Dentisterie
Année:
2018
Type:
Article
Pays d'affiliation:
Brésil
Institution/Pays d'affiliation:
University of São Paulo/BR
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