Glass transition and degree of conversion of a light-cured orthodontic composite
J. appl. oral sci
;
17(6): 570-573, Nov.-Dec. 2009. graf, tab
Article
in English
| LILACS
| ID: lil-534421
ABSTRACT
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 ANDMETHODS:
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 (35-84ºC versus 135ºC), 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/cm² is necessary to reach adequate conversion level and obtain satisfactory adhesion.
Full text:
Available
Index:
LILACS (Americas)
Main subject:
Orthodontic Brackets
/
Composite Resins
/
Resin Cements
/
Transition Temperature
/
Glass
Limits:
Humans
Language:
English
Journal:
J. appl. oral sci
Journal subject:
Dentistry
Year:
2009
Type:
Article
Affiliation country:
Brazil
Institution/Affiliation country:
São Paulo State University/BR
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