Effectiveness of second-generation light-emitting diode (LED) light curing units.
OBJECTIVE
The purpose of this study was to evaluate the effectiveness of three commercially available light emitting diode (LED) light curing units (LCU) (Elipar FreeLight--3M ESPE; UltraLume LED2--Ultradent; and Single V--BioArt) for polymerizing Z250-A3 composite (3M ESPE) using Knoop hardness, polymerization depth, and flexural strength properties.


METHODS
The XL 2500 (3M ESPE) LCU, which is a conventional halogen unit, was used as a control. In all cases the curing time was 20 seconds. Hardness was determined 24 hours after composite cure for 10 samples of 8 mm diameter and 2 mm height for each LCU tested. Samples were stored dry in a light-proof container prior to testing. The depth of cure of the composite was measured immediately after composite polymerization for each LCU using three samples 4 mm in diameter and 6 mm in height. Flexural strength was determined for five samples 24 hours after immersion in distilled water at 37 degrees C. Each sample measured 25 mm in length, 2 mm in width, and 2 mm in height for each LCU tested.


CONCLUSIONS
The results were treated statistically for comparison of the LCUs. In all cases the results obtained by LED LCUs were not different or were higher than a conventional halogen LCU.


CONCLUSIONS
Second generation LED LCUs were as effective as/or more effective than a halogen LCU for polymerization of the used composite. The present study shows second generation LEDs have the potential to replace halogen LCUs.
Campregher
Ulisses Bastos
UB
Department of Conservative Dentistry, Federal University of Rio Grande do Sul, Porto Algere, Rio Grande do Sul, Brazil. ubcampre@ufrgs.br
Samuel
Susana Maria Werner
SM
Fortes
Carmen Beatriz Borges
CB
Medina
Alberth David Correa
AD
Collares
Fabricio Mezzomo
FM
Ogliari
Fabricio Aulo
FA
D000704:Analysis of Variance; D003188:Composite Resins / Q000528:radiation effects*; D003748:Dental Equipment; D003799:Dental Stress Analysis; D006219:Halogens; D006244:Hardness; D008027:Light; D044367:Phase Transition; D018583:Pliability; D019279:Resin Cements / Q000528:radiation effects*; D012666:Semiconductors
D003188:Composite Resins; C444701:Filtek Z250; D006219:Halogens; D019279:Resin Cements