title: Knoop microhardness and FT-Raman evaluation of composite resins: influence of opacity and photoactivation source.
abstract: The aim of this study was to evaluate the degree of conversion by Knoop microhardness (KHN) and FT-Raman spectroscopy (FTIR) of one nanofilled (Filtek Supreme-3M-ESPE [FS]) and one microhybrid composite (Charisma-Heraeus-Kulzer [CH]), each with different opacities, namely enamel, dentin, and translucent, which were photo-activated by a quartz-tungsten-halogen lamp (QTH) and a light-emitting diode (LED). Resin was bulk inserted into a disc-shaped mold that was 2.0 mm thick and 4 mm in diameter, obtaining 10 samples per group. KHN and FTIR values were analyzed by two-way ANOVA and Tukey's tests (α = 0.05). Nanofilled resin activated by a LED presented higher microhardness values than samples activated by a QTH for dentin opacity (p < 0.05). The microhybrid resin showed no differences in KHN or FTIR values with different activation sources or opacity. The nanofilled dentin and enamel resins showed lower FTIR values than the translucent resin. The KHN values of the translucent resins were not influenced by the light source.
authors.affiliation: Department of Restorative Dentistry, Graduate Division, Guarulhos University, Guarulhos, SP, Brazil.
authors.forename: Luis Gustavo Barrotte
authors.initials: LG
authors.lastname: Albino
authors.forename: José Augusto
authors.initials: JA
authors.lastname: Rodrigues
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Kawano
authors.forename: Alessandra
authors.initials: A
authors.lastname: Cassoni
mesh_terms: D000704:Analysis of Variance; D003188:Composite Resins / Q000737:chemistry* / Q000528:radiation effects*; D055117:Curing Lights, Dental; D003743:Dental Enamel / Q000737:chemistry; D003804:Dentin / Q000737:chemistry; D006245:Hardness Tests; D008422:Materials Testing; D058105:Polymerization; D013059:Spectrum Analysis, Raman; D013499:Surface Properties; D013997:Time Factors
chemical_list: C084111:Charisma composite resin; D003188:Composite Resins; C474035:Filtek Supreme