title: Microhardness of intracoronal dentin exposed to bleaching and fluoride treatment.
abstract: OBJECTIVE
  The aim of this study was to assess the surface microhardness (SMH) of intracoronal dentin exposed to 38% hydrogen peroxide (HP) light-activated or not and to 2% sodium fluoride gel (F2%) or 5% varnish (F5%).
  
  
  METHODS
  Intracoronal dentin specimens were exposed to bleaching (B), bleaching and light activation (BL), or no bleaching (NB), followed by F2%, F5%, or no exposure (NF). SMH test was performed. Four specimens of each group were analyzed by scanning electron microscopy (SEM).
  
  
  RESULTS
  Analysis of variance and Tukey test (α = 5%) showed higher SMH of NB than BL or B. Specimens exposed to F5% presented the highest SMH and differed from F2% and NF. BL + NF yielded inferior SMH and was similar to B + NF, BL + F2%, B + F2%, BL + F5%, and NB + NF. NB + F5% showed superior values and did not differ from NB + F2%, B + F5%, and NB + NF.
  
  
  CONCLUSIONS
  Bleaching with 38% HP, light-activated or not, reduced the SMH of intracoronal dentin. F5% provided SMH to the level of unbleached specimens.
authors.affiliation: School of Dentistry, University of Ribeirão Preto, Ribeirão Preto, Brazil.
authors.forename: Felipe
authors.initials: F
authors.lastname: Barros-Matoso
authors.forename: Aline Evangelista
authors.initials: AE
authors.lastname: de Souza-Gabriel
authors.forename: Danielle Cristine
authors.initials: DC
authors.lastname: Furtado-Messias
authors.forename: Manoel Damião
authors.initials: MD
authors.lastname: de Sousa-Neto
authors.forename: Edson
authors.initials: E
authors.lastname: Alfredo
mesh_terms: D000704:Analysis of Variance; D003481:Cuspid; D003786:Dental Pulp Cavity / Q000187:drug effects / Q000648:ultrastructure; D003799:Dental Stress Analysis; D003804:Dentin / Q000187:drug effects* / Q000648:ultrastructure; D004305:Dose-Response Relationship, Drug; D004359:Drug Therapy, Combination; D005460:Fluorides, Topical / Q000494:pharmacology*; D006244:Hardness / Q000187:drug effects*; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology*; D008437:Maxilla; D018709:Statistics, Nonparametric; D014073:Tooth Bleaching / Q000009:adverse effects / Q000379:methods; D058205:Tooth Bleaching Agents / Q000494:pharmacology*; D014075:Tooth Discoloration / Q000188:drug therapy* / Q000209:etiology; D019553:Tooth, Nonvital / Q000150:complications
chemical_list: D005460:Fluorides, Topical; D058205:Tooth Bleaching Agents; D006861:Hydrogen Peroxide