title: Hardness of a bleaching-shade resin composite polymerized with different light-curing sources.
abstract: The microhardness of a bleaching-shade resin composite polymerized with different light-curing units was evaluated. Composite samples (3M ESPE Filtek Supreme) were applied to brass rings (2 mm in thickness, 5 mm in diameter). Three commercial LED lights were used to polymerize the specimens and the results were compared to those of a conventional halogen light. The light sources used in the present study were: Demetron Optilux 401 (QTH), 3M ESPE Elipar FreeLight (LED 1); Kerr L.E. Demetron I (LED 2), and ColtoluxLED lights (LED 3). The microhardness of the top and bottom surfaces was assessed with a digital Vickers hardness-measuring instrument, under load. At the bottom surface, no significant difference among the light sources was observed (two-way ANOVA). At the top surface, the QTH light source presented significantly higher hardness values compared to the values observed when LED 1 and LED 3 were used. There were no significant differences between the QTH and LED 2 light sources. Significantly higher hardness values were also found at the top surface when compared to the values observed at the bottom surface. The power density of the polymerization light sources seemed to be responsible for the observed resin composite hardness, not their irradiance.
authors.affiliation: School of Dentistry, University of Ponta Grossa.
authors.forename: Giovana Mongruel
authors.initials: GM
authors.lastname: Gomes
authors.forename: Abraham Lincoln
authors.initials: AL
authors.lastname: Calixto
authors.forename: Fabio André Dos
authors.initials: FA
authors.lastname: Santos
authors.forename: Osnara Maria Mongruel
authors.initials: OM
authors.lastname: Gomes
authors.forename: Paulo Henrique Perlatti
authors.initials: PH
authors.lastname: D'Alpino
authors.forename: João Carlos
authors.initials: JC
authors.lastname: Gomes
mesh_terms: D000704:Analysis of Variance; D003188:Composite Resins / Q000737:chemistry* / Q000528:radiation effects; D003748:Dental Equipment; D006244:Hardness; D008027:Light; D008422:Materials Testing; D011108:Polymers / Q000737:chemistry*; D013053:Spectrophotometry; D013499:Surface Properties; D014073:Tooth Bleaching
chemical_list: D003188:Composite Resins; D011108:Polymers