title: Influence of two different methods of delivering fluoride on bond strength and degree of conversion of an adhesive after bleaching.
abstract: OBJECTIVE
  To evaluate the influence of fluoride delivery and restoration time point on the microshear bond strength (mSBS) and degree of conversion (DC) values of an adhesive applied on bleached enamel.
  
  
  METHODS
  Fifty-four enamel specimens were submitted to bleaching and divided into 3 groups of n = 18: group HP: 35% hydrogen peroxide (HP); group HPF: HP + 1.23% sodium fluoride application (F); group PF: 38% HP with F. A control group of n = 6 was neither bleached nor fluoridated. Subsequently, each group except the control was subdivided into 3 subgroups (n = 6) to be restored immediately, or at 7 or 14 days. Tygon tubes were filled with composite resin and placed on enamel surfaces, then the mSBS test was performed. The DC of the interface was observed with Raman spectroscopy. The data were submitted to two-way ANOVA and Tukey's and Dunnet's post-hoc test (α = 0.05).
  
  
  RESULTS
  The mSBS results showed higher values for groups HP and HPF at 14 days compared with immediate and 7 days (p < 0.05). Lower DC values were obtained in the immediately restored groups HP and HPF, which were significantly different from 7 and 14 days (p < 0.05). mSBS and DC for group PF was similar at all restoration time points and to the control group (p > 0.05).
  
  
  CONCLUSIONS
  Only the use of a fluoridated in-office bleaching agent (Opalescence Boost PF) proved to be effective for immediately reversing the side effects of low mSBS and DC values when in-office bleaching is used.
authors.forename: Bruna Fortes
authors.initials: BF
authors.lastname: Bittencourt
authors.forename: John Alexis
authors.initials: JA
authors.lastname: Dominguez
authors.forename: Alessandro D
authors.initials: AD
authors.lastname: Loguercio
authors.forename: João Carlos
authors.initials: JC
authors.lastname: Gomes
authors.forename: Osnara Maria
authors.initials: OM
authors.lastname: Gomes
mesh_terms: D002327:Cariostatic Agents / Q000008:administration & dosage* / Q000737:chemistry; D003188:Composite Resins / Q000737:chemistry; D001840:Dental Bonding; D003738:Dental Cements / Q000737:chemistry*; D003743:Dental Enamel / Q000187:drug effects / Q000648:ultrastructure; D003793:Dental Restoration, Permanent / Q000379:methods; D003799:Dental Stress Analysis / Q000295:instrumentation; D005459:Fluorides / Q000008:administration & dosage* / Q000737:chemistry; D005460:Fluorides, Topical / Q000008:administration & dosage / Q000737:chemistry; D006801:Humans; D006861:Hydrogen Peroxide / Q000008:administration & dosage / Q000737:chemistry; D008422:Materials Testing; D058105:Polymerization; D033081:Shear Strength; D012969:Sodium Fluoride / Q000008:administration & dosage / Q000737:chemistry; D013059:Spectrum Analysis, Raman; D013314:Stress, Mechanical; D013499:Surface Properties; D013997:Time Factors; D014073:Tooth Bleaching / Q000379:methods*; D058205:Tooth Bleaching Agents / Q000008:administration & dosage / Q000737:chemistry
chemical_list: D002327:Cariostatic Agents; D003188:Composite Resins; D003738:Dental Cements; D005460:Fluorides, Topical; D058205:Tooth Bleaching Agents; D012969:Sodium Fluoride; D006861:Hydrogen Peroxide; D005459:Fluorides