Glass transition and degree of conversion of a light-cured orthodontic composite.
J Appl Oral Sci
; 17(6): 570-3, 2009.
Article
em En
| MEDLINE
| ID: mdl-20027428
OBJECTIVE: This study evaluated the glass transition temperature (Tg) and degree of conversion (DC) of a light-cured (Fill Magic) versus a chemically cured (Concise) orthodontic composite. MATERIAL AND METHODS: Anelastic relaxation spectroscopy was used for the first time to determine the Tg of a dental composite, while the DC was evaluated by infrared spectroscopy. The light-cured composite specimens were irradiated with a commercial LED light-curing unit using different exposure times (40, 90 and 120 s). RESULTS: Fill Magic presented lower Tg than Concise (35-84 masculineC versus 135 masculineC), but reached a higher DC. CONCLUSIONS: The results of this study suggest that Fill Magic has lower Tg than Concise due to its higher organic phase content, and that when this light-cured composite is used to bond orthodontic brackets, a minimum energy density of 7.8 J/cm(2) is necessary to reach adequate conversion level and obtain satisfactory adhesion.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Braquetes Ortodônticos
/
Resinas Compostas
/
Cimentos de Resina
/
Temperatura de Transição
/
Vidro
Limite:
Humans
Idioma:
En
Revista:
J Appl Oral Sci
Assunto da revista:
ODONTOLOGIA
Ano de publicação:
2009
Tipo de documento:
Article
País de afiliação:
Brasil
País de publicação:
Brasil