title: Cytotoxicity of universal, self-etching and etch-and-rinse adhesive systems according to the polymerization time.
abstract: This in vitro study evaluated in fibroblast cultures the direct cytotoxicity of universal, self-etching and etch-and-rinse adhesive systems according to the polymerization time. Paper discs were impregnated with adhesives and light-cured (10, 20 or 40 s). The discs were then immersed in culture medium to obtain the eluates for the experimental groups (A1-Single Bond 2; A2-Scotchbond Multi-purpose; A3-Clearfil SE Bond; A4 Scotchbond Universal). As a negative control, paper discs were immersed in culture medium only. After 24 h or 7 days, the eluate obtained was applied on fibroblast culture. Cell viability, cell morphology, membrane damage and the presence of residual monomers were evaluated by MTT assay, SEM, flow cytometry and high-performance liquid chromatography (HPLC), respectively. Data were analyzed by Kruskal-Wallis and Mann-Whitney tests (=0.05). All adhesive systems significantly reduced 33-51% cell metabolism when compared to the negative control, regardless of polymerization time, storage period and adhesive system. Moreover, the adhesives caused intense morphological alterations and cell membrane damage. Toxicity was directly related to the presence of residual monomers in the eluates. Residual monomers and additional components are capable of reducing mitochondrial activity, causing morphological alterations and disruption of the cell membrane in fibroblasts, regardless of the polymerization time. This study highlights that despite the more complex composition of the universal adhesive system, its biological response was not more toxic when compared with other systems, even when the shortest polymerization time was tested in cell culture.
authors.affiliation: Laboratory of Oral Histopathology, Department of Dentistry, School of Health Sciences, UNB - University of Brasilia, Brasilia, DF, Brazil.
authors.forename: Silvia T
authors.initials: ST
authors.lastname: Elias
authors.affiliation: Department of Dentistry, School of Health Sciences, UNB - University of Brasilia, Brasilia, DF, Brazil.
authors.forename: Andressa F Dos
authors.initials: AF
authors.lastname: Santos
authors.affiliation: Department of Dentistry, School of Health Sciences, UNB - University of Brasilia, Brasilia, DF, Brazil.
authors.forename: Fernanda C P
authors.initials: FC
authors.lastname: Garcia
authors.affiliation: Department of Dentistry, School of Health Sciences, UNB - University of Brasilia, Brasilia, DF, Brazil.
authors.forename: Patrícia N R
authors.initials: PN
authors.lastname: Pereira
authors.affiliation: Department of Dentistry, School of Health Sciences, UNB - University of Brasilia, Brasilia, DF, Brazil.
authors.forename: Leandro A
authors.initials: LA
authors.lastname: Hilgert
authors.affiliation: Department of Pharmaceutical Sciences, School of Health Sciences, UNB - University of Brasilia, Brasilia, DF, Brazil.
authors.forename: Yris M
authors.initials: YM
authors.lastname: Fonseca-Bazzo
authors.affiliation: Laboratory of Oral Histopathology, Department of Dentistry, School of Health Sciences, UNB - University of Brasilia, Brasilia, DF, Brazil.
authors.forename: Eliete N S
authors.initials: EN
authors.lastname: Guerra
authors.affiliation: Department of Dentistry, School of Health Sciences, UNB - University of Brasilia, Brasilia, DF, Brazil.
authors.forename: Ana Paula Dias
authors.initials: AP
authors.lastname: Ribeiro
mesh_terms: D017438:Bisphenol A-Glycidyl Methacrylate; D002851:Chromatography, High Pressure Liquid; D045662:Dental Etching / Q000379:methods*; D017220:Dentin-Bonding Agents / Q000633:toxicity*; D005347:Fibroblasts / Q000187:drug effects*; D005434:Flow Cytometry; D066298:In Vitro Techniques; D055115:Light-Curing of Dental Adhesives; D008855:Microscopy, Electron, Scanning; D058105:Polymerization; D019279:Resin Cements; D013499:Surface Properties; D013997:Time Factors
chemical_list: C438313:Clearfil SE Bond; D017220:Dentin-Bonding Agents; D019279:Resin Cements; C084018:Scotchbond Multi-Purpose; C115612:single bond; D017438:Bisphenol A-Glycidyl Methacrylate; C041330:Scotchbond