title: Influence of coffee on reflectance and chemistry of resin composite protected by surface sealant.
abstract: OBJECTIVE
  To assess the influence of the light-curing unit type and whether or not it was worth using surface sealant protection on resin composite restorative materials stained by coffee. Another objective was to propose the monitoring of coffee staining by FT-Raman spectroscopy using carbon-hydrogen (C-H) bonds as reference to the composite matrix degradation.
  
  
  METHODS
  Sixty cylindrical specimens of resin composite were prepared and divided into six groups: HC (control)--cured with a halogen light; LC (control) cured with a LED; HF--cured with a halogen light + Fortify Plus; LF--cured with a LED + Fortify Plus; HP--cured with a halogen light + PermaSeal; LP--cured with a LED + PermaSeal. After storage for 24 hours at 37% and 100% of relative humidity, the top surface was protected, and the other surfaces isolated. Polishing with paper discs was performed after 24 hours of curing and prior to FT-Raman spectroscopy and reflectance measurements. All specimens were submitted to coffee staining for 14 days and evaluated by both systems. Results were statistically analyzed by ANOVA and Tukey tests.
  
  
  RESULTS
  FT-Raman spectrum only showed significant changes in groups LC and LP (P< 0.05). Reflectance demonstrated that staining was present in all specimens protected by sealants. Sealant staining was larger in the HF (P < 0.001) group.
authors.affiliation: Biomedical Vibrational Spectroscopy Laboratory, Research and Development Institute, University of Vale do Paraiba-UNIVAP, Av. Shishima Hifumi, 2911, Urbanova, 12,244-000, São José dos Campos, SP, Brazil. lesoares@univap.br
authors.forename: Luís Eduardo Silva
authors.initials: LE
authors.lastname: Soares
authors.forename: Ilene Cristine Rosia
authors.initials: IC
authors.lastname: Cesar
authors.forename: Carla Gabriela Couto
authors.initials: CG
authors.lastname: Santos
authors.forename: Ana Luiza Merigo Oliveira
authors.initials: AL
authors.lastname: De Cardoso
authors.forename: Priscila Christiane Suzy
authors.initials: PC
authors.lastname: Liporoni
authors.forename: Egberto
authors.initials: E
authors.lastname: Munin
authors.forename: Airton Abrahão
authors.initials: AA
authors.lastname: Martin
mesh_terms: D002244:Carbon / Q000737:chemistry; D003069:Coffee / Q000737:chemistry*; D003116:Color; D003188:Composite Resins / Q000737:chemistry*; D003764:Dental Materials / Q000737:chemistry*; D003775:Dental Polishing; D006801:Humans; D006813:Humidity; D006859:Hydrogen / Q000737:chemistry; D006860:Hydrogen Bonding; D008029:Lighting / Q000295:instrumentation; D008422:Materials Testing; D055095:Optics and Photonics; D019279:Resin Cements / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared; D013059:Spectrum Analysis, Raman; D013499:Surface Properties; D013997:Time Factors
chemical_list: D003069:Coffee; D003188:Composite Resins; D003764:Dental Materials; C095811:Fortify sealant; D019279:Resin Cements; D002244:Carbon; D006859:Hydrogen