title: Relationship between the degree of conversion, solubility and salivary sorption of a hybrid and a nanofilled resin composite.
abstract: This study analyzed the relationship between the degree of conversion (DC), solubility, and salivary sorption of a hybrid (Filtek P 60) and a nanofilled resin composite (Filtek Supreme), and evaluated the influence of the light-activation mode on these properties. Two light-activation modes were used: Conventional (C; 850 mW/cm(2) for 20 s) and Soft-start (SS; 100-1,000 mW/cm(2) for 10 s + 1,000 mW/cm(2) for 10 s). The DC (%) was evaluated by FT-Raman spectroscopy. The solubility and salivary sorption were measured after immersion in artificial saliva for 7 days. Data were analyzed by ANOVA and Student-Newman-Keuls' test and linear regression analysis (a = 0.05). The DC varied from 50.52% (nanofilled composite) to 57.15% (hybrid composite), and was influenced by the light-activation mode: C > SS. The solubility (0.45 microg/mm(3)) and salivary sorption (8.04 microg/mm(3)) of the nanofilled composite were greater than those of the hybrid composite (0.40 microg/mm(3) / 6.87 microg/mm(3)), and were influenced by the light-activation mode: SS > C. Correlation was found between DC and solubility (r = - 0.89, p<0.05), as well as between solubility and salivary sorption (r = 0.95). These findings suggest that nanofilled composites may present higher degradation in the oral environment than hybrid ones. Soft-start light-activation mode may increase the solubility of resin composites.
authors.affiliation: Department of Restorative Dentistry, School of Dentistry, Federal Fluminense University, Niterói, Rio de Janeiro, Brazil. emsilva@vm.uff.br
authors.forename: Eduardo Moreira
authors.initials: EM
authors.lastname: da Silva
authors.forename: Giselle Soares
authors.initials: GS
authors.lastname: Almeida
authors.forename: Laiza Tatiana
authors.initials: LT
authors.lastname: Poskus
authors.forename: José Guilherme Antunes
authors.initials: JG
authors.lastname: Guimarães
mesh_terms: D000042:Absorption; D000327:Adsorption; D055598:Chemical Phenomena; D003188:Composite Resins / Q000737:chemistry*; D055117:Curing Lights, Dental; D003764:Dental Materials / Q000737:chemistry*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008422:Materials Testing; D053761:Nanocomposites / Q000737:chemistry*; D044367:Phase Transition; D011829:Radiation Dosage; D012464:Saliva, Artificial / Q000737:chemistry*; D012995:Solubility; D017550:Spectroscopy, Fourier Transform Infrared; D013059:Spectrum Analysis, Raman; D013499:Surface Properties; D013696:Temperature; D013997:Time Factors
chemical_list: D003188:Composite Resins; D003764:Dental Materials; C438835:Filtek P60 Composite Resin; C474035:Filtek Supreme; D012464:Saliva, Artificial