Sintering dental porcelain with CO2 laser: porosity and mechanical characterization

Detalhes bibliográficos
Autor(a) principal: Sgura, Ricardo
Data de Publicação: 2013
Outros Autores: Reis, Mariana Cavalcante, Andreeta, Marcello Rubens Barsi, Hernandes, Antônio Carlos, Medeiros, Igor Studart
Tipo de documento: Artigo
Idioma: eng
Título da fonte: Brazilian Dental Science
Texto Completo: https://ojs.ict.unesp.br/index.php/cob/article/view/856
Resumo: Aim: This work evaluated dental porcelain sintering by CO2 laser irradiation. Methods: Two commercial veneering porcelains were used: VM7 and VM9 (VITA Zahnfabrik).  Porcelain disks (0.35 mm dia. x 2.0 mm) were sintered by a continuous CO2 laser (Coherent, USA – 35 W e ?= 10.6 ?m) in two irradiances (20 and 23 W/cm2) and exposure times: 5 and 10 min. A control group was sintered in a conventional oven following manufacturer’s instructions. After sintering, one of the disks surfaces was mirror polished. Superficial pores (%) were assessed by images obtained in an optical microscope (100x) submitted to the software Image J analysis. Apparent density was measured by Archimedean’s method. Microhardness and fracture toughness (Indentation Fracture - IF) were determined with a Vickers indenter (Shimadzu). Results: Porosity ranged between 4.0 and 5.9% for irradiated specimens; control group had 6.0 and 4.7% of porosity for porcelain VM7 and VM9 respectively. Density of porcelain VM7 irradiated for 10 min. with irradiance of 23 W/cm2 was significantly higher than control group. Microhardness and fracture toughness of irradiated specimens were similar to control. The measurements of some irradiated groups were not possible to achieve because the tests revealed irregular marks after indentation. Conclusions: Porcelain sintering with CO2 laser in some fluences produced a material with superficial porosity similar to that obtained in conventional oven. Microhardness and fracture toughness could not be measured for all irradiated groups suggesting some subsuperficial defect caused by entrapped gases or cracks originated by temperature gradient along the specimen.
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spelling Sintering dental porcelain with CO2 laser: porosity and mechanical characterizationAim: This work evaluated dental porcelain sintering by CO2 laser irradiation. Methods: Two commercial veneering porcelains were used: VM7 and VM9 (VITA Zahnfabrik).  Porcelain disks (0.35 mm dia. x 2.0 mm) were sintered by a continuous CO2 laser (Coherent, USA – 35 W e ?= 10.6 ?m) in two irradiances (20 and 23 W/cm2) and exposure times: 5 and 10 min. A control group was sintered in a conventional oven following manufacturer’s instructions. After sintering, one of the disks surfaces was mirror polished. Superficial pores (%) were assessed by images obtained in an optical microscope (100x) submitted to the software Image J analysis. Apparent density was measured by Archimedean’s method. Microhardness and fracture toughness (Indentation Fracture - IF) were determined with a Vickers indenter (Shimadzu). Results: Porosity ranged between 4.0 and 5.9% for irradiated specimens; control group had 6.0 and 4.7% of porosity for porcelain VM7 and VM9 respectively. Density of porcelain VM7 irradiated for 10 min. with irradiance of 23 W/cm2 was significantly higher than control group. Microhardness and fracture toughness of irradiated specimens were similar to control. The measurements of some irradiated groups were not possible to achieve because the tests revealed irregular marks after indentation. Conclusions: Porcelain sintering with CO2 laser in some fluences produced a material with superficial porosity similar to that obtained in conventional oven. Microhardness and fracture toughness could not be measured for all irradiated groups suggesting some subsuperficial defect caused by entrapped gases or cracks originated by temperature gradient along the specimen.Institute of Science and Technology of São José dos Campos2013-03-28info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersionapplication/pdfhttps://ojs.ict.unesp.br/index.php/cob/article/view/85610.14295/bds.2013.v16i1.856Brazilian Dental Science; Vol. 16 No. 1 (2013): Jan. - Mar. / 2013 - Published March 2013; 46-52Brazilian Dental Science; v. 16 n. 1 (2013): Jan. - Mar. / 2013 - Published March 2013; 46-522178-6011reponame:Brazilian Dental Scienceinstname:Universidade Estadual Paulista Júlio de Mesquita Filho (UNESP)instacron:UNESPenghttps://ojs.ict.unesp.br/index.php/cob/article/view/856/786Sgura, RicardoReis, Mariana CavalcanteAndreeta, Marcello Rubens BarsiHernandes, Antônio CarlosMedeiros, Igor Studartinfo:eu-repo/semantics/openAccess2020-01-28T12:37:49Zoai:ojs.pkp.sfu.ca:article/856Revistahttp://bds.ict.unesp.br/PUBhttp://ojs.fosjc.unesp.br/index.php/index/oaisergio@fosjc.unesp.br||sergio@fosjc.unesp.br2178-60112178-6011opendoar:2022-11-08T16:29:52.403067Brazilian Dental Science - Universidade Estadual Paulista Júlio de Mesquita Filho (UNESP)true
dc.title.none.fl_str_mv Sintering dental porcelain with CO2 laser: porosity and mechanical characterization
title Sintering dental porcelain with CO2 laser: porosity and mechanical characterization
spellingShingle Sintering dental porcelain with CO2 laser: porosity and mechanical characterization
Sgura, Ricardo
title_short Sintering dental porcelain with CO2 laser: porosity and mechanical characterization
title_full Sintering dental porcelain with CO2 laser: porosity and mechanical characterization
title_fullStr Sintering dental porcelain with CO2 laser: porosity and mechanical characterization
title_full_unstemmed Sintering dental porcelain with CO2 laser: porosity and mechanical characterization
title_sort Sintering dental porcelain with CO2 laser: porosity and mechanical characterization
author Sgura, Ricardo
author_facet Sgura, Ricardo
Reis, Mariana Cavalcante
Andreeta, Marcello Rubens Barsi
Hernandes, Antônio Carlos
Medeiros, Igor Studart
author_role author
author2 Reis, Mariana Cavalcante
Andreeta, Marcello Rubens Barsi
Hernandes, Antônio Carlos
Medeiros, Igor Studart
author2_role author
author
author
author
dc.contributor.author.fl_str_mv Sgura, Ricardo
Reis, Mariana Cavalcante
Andreeta, Marcello Rubens Barsi
Hernandes, Antônio Carlos
Medeiros, Igor Studart
description Aim: This work evaluated dental porcelain sintering by CO2 laser irradiation. Methods: Two commercial veneering porcelains were used: VM7 and VM9 (VITA Zahnfabrik).  Porcelain disks (0.35 mm dia. x 2.0 mm) were sintered by a continuous CO2 laser (Coherent, USA – 35 W e ?= 10.6 ?m) in two irradiances (20 and 23 W/cm2) and exposure times: 5 and 10 min. A control group was sintered in a conventional oven following manufacturer’s instructions. After sintering, one of the disks surfaces was mirror polished. Superficial pores (%) were assessed by images obtained in an optical microscope (100x) submitted to the software Image J analysis. Apparent density was measured by Archimedean’s method. Microhardness and fracture toughness (Indentation Fracture - IF) were determined with a Vickers indenter (Shimadzu). Results: Porosity ranged between 4.0 and 5.9% for irradiated specimens; control group had 6.0 and 4.7% of porosity for porcelain VM7 and VM9 respectively. Density of porcelain VM7 irradiated for 10 min. with irradiance of 23 W/cm2 was significantly higher than control group. Microhardness and fracture toughness of irradiated specimens were similar to control. The measurements of some irradiated groups were not possible to achieve because the tests revealed irregular marks after indentation. Conclusions: Porcelain sintering with CO2 laser in some fluences produced a material with superficial porosity similar to that obtained in conventional oven. Microhardness and fracture toughness could not be measured for all irradiated groups suggesting some subsuperficial defect caused by entrapped gases or cracks originated by temperature gradient along the specimen.
publishDate 2013
dc.date.none.fl_str_mv 2013-03-28
dc.type.driver.fl_str_mv info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
format article
status_str publishedVersion
dc.identifier.uri.fl_str_mv https://ojs.ict.unesp.br/index.php/cob/article/view/856
10.14295/bds.2013.v16i1.856
url https://ojs.ict.unesp.br/index.php/cob/article/view/856
identifier_str_mv 10.14295/bds.2013.v16i1.856
dc.language.iso.fl_str_mv eng
language eng
dc.relation.none.fl_str_mv https://ojs.ict.unesp.br/index.php/cob/article/view/856/786
dc.rights.driver.fl_str_mv info:eu-repo/semantics/openAccess
eu_rights_str_mv openAccess
dc.format.none.fl_str_mv application/pdf
dc.publisher.none.fl_str_mv Institute of Science and Technology of São José dos Campos
publisher.none.fl_str_mv Institute of Science and Technology of São José dos Campos
dc.source.none.fl_str_mv Brazilian Dental Science; Vol. 16 No. 1 (2013): Jan. - Mar. / 2013 - Published March 2013; 46-52
Brazilian Dental Science; v. 16 n. 1 (2013): Jan. - Mar. / 2013 - Published March 2013; 46-52
2178-6011
reponame:Brazilian Dental Science
instname:Universidade Estadual Paulista Júlio de Mesquita Filho (UNESP)
instacron:UNESP
instname_str Universidade Estadual Paulista Júlio de Mesquita Filho (UNESP)
instacron_str UNESP
institution UNESP
reponame_str Brazilian Dental Science
collection Brazilian Dental Science
repository.name.fl_str_mv Brazilian Dental Science - Universidade Estadual Paulista Júlio de Mesquita Filho (UNESP)
repository.mail.fl_str_mv sergio@fosjc.unesp.br||sergio@fosjc.unesp.br
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