title: Effect of photoactivation systems and resin composites on the microleakage of esthetic restorations.
abstract: OBJECTIVE
  The aim of this study was to evaluate the influence of four photoactivation systems [quartz tungsten halogen (QTH), light-emitting diode (LED), argon ion laser (AL), and plasma arc curing PAC)] on cementum/dentin and enamel microleakage of Class II restorations using a microhybrid [Z250-3M ESPE] and two packable composites [(SureFil-Dentsply and Tetric Ceram HB-Ivoclair/Vivadent].
  
  
  METHODS
  Three hundred sixty "vertical-slot Class II cavities" were prepared at the mesial surface of bovine incisors using a 245 carbide bur in a highspeed handpiece. Specimens were divided into twelve groups (composite-photoactivation systems). Half of the specimens had the gingival margin placed in enamel (n=15) and the other half in cementum/dentin (n=15). Composites were inserted and cured in 2 mm increments according to manufacturers' recommended exposure times. After polishing, the samples were immersed in 2% methylene blue solution, sectioned, and evaluated at the gingival margins. Data were submitted to statistical analysis using the Kruskal-Wallis and Mann-Whitney tests.
  
  
  RESULTS
  No significant differences were found among the photoactivation systems and among resin composites (p>0.05). Microleakage was not significantly affected by location (enamel vs. cementum/dentin, p>0.05). These findings suggested neither the photoactivation systems nor the resin composite types might have an effect on the microleakage at gingival margins Class II cavities.
authors.affiliation: Clinical Dentistry Program, Department of Restorative Dentistry, School of Dentistry, Unviersity of Campinas, Piracicaba, SP, Brazil. lacavalcante@fop.unicamp.br
authors.forename: Larissa Maria Assad
authors.initials: LM
authors.lastname: Cavalcante
authors.forename: Alessandra Resende
authors.initials: AR
authors.lastname: Peris
authors.forename: Glaucia Maria Bovi
authors.initials: GM
authors.lastname: Ambrosano
authors.forename: Andre Vicente
authors.initials: AV
authors.lastname: Ritter
authors.forename: Luiz Andre Freire
authors.initials: LA
authors.lastname: Pimenta
mesh_terms: D000818:Animals; D002417:Cattle; D003188:Composite Resins / Q000528:radiation effects*; D003737:Dental Cavity Preparation; D003748:Dental Equipment; D003763:Dental Leakage / Q000517:prevention & control*; D018772:Dental Marginal Adaptation; D003793:Dental Restoration, Permanent / Q000379:methods*; D006219:Halogens; D007834:Lasers; D008027:Light; D044367:Phase Transition; D011897:Random Allocation; D012666:Semiconductors; D018709:Statistics, Nonparametric; D014978:Xenon
chemical_list: D003188:Composite Resins; C444701:Filtek Z250; D006219:Halogens; C403464:SureFil packable composite; C121818:Tetric ceram; D014978:Xenon