Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
10
pubmed:dateCreated
2003-2-20
pubmed:abstractText
Light curing units (LCUs) are used for the polymerization of dental composites. Recent trends in light curing technology include replacing the halogen LCUs with LCUs using light emitting diodes (LEDs) reducing curing times and varying the LCUs light output within a curing cycle. This study investigated the time dependence of the Knoop hardness and depth of cure of dental composites polymerized with a halogen LCU (Trilight) and two LED LCUs (the commercial Freelight and custom-made LED LCU prototype). The halogen LCU was used in the soft-start (exponential increase of output power) and standard mode. Four dental composites (Z100, Spectrum, Definite, Solitaire2) were selected, two of them (Definite, Solitaire2) contain co-initiators in addition to the standard photoinitiator camphorquinone. The depth of cure obtained with the Trilight in the standard mode was statistically significantly greater (p < 0.05) than that obtained with the LED LCUs for all materials and curing times. The custom made LED LCU prototype (LED63) achieved a statistically significantly greater depth of cure than the commercial LED LCU Freelight for all materials and curing times. There was no statistical difference in Knoop hardness at the 95% confidence level at the surface of the 2 mm thick sample between the LED63 or Trilight (standard mode) for the composite Z100 for all times, and for Spectrum for 20s and 40s curing time. The composites containing co-initiators showed statistically significantly smaller hardness values at the top and bottom of the samples if LED LCUs were used instead of halogen LCUs. The experiment revealed that the depth of cure test does not and the Knoop hardness test does discriminate between LCUs, used for the polymerization of composites containing photoinitiators in addition to camphorquinone.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
0142-9612
pubmed:author
pubmed:copyrightInfo
Copyright 2002 Elsevier Science Ltd.
pubmed:issnType
Print
pubmed:volume
24
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1787-95
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
2003
pubmed:articleTitle
Photoinitiator dependent composite depth of cure and Knoop hardness with halogen and LED light curing units.
pubmed:affiliation
Institute of Materials Science and Technology, Friedrich-Schiller-University Jena, Löbdergraben 32, D-07743 Jena, Germany.
pubmed:publicationType
Journal Article, Comparative Study, In Vitro