title: Role of chlorhexidine in bond strength to artificially eroded dentin over time.
abstract: OBJECTIVE
  To assess the long-term effect of a 2% aqueous chlorhexidine (CHX) solution on bond strength to artificially eroded dentin compared to sound dentin.
  
  
  METHODS
  Flat mid-coronal dentin surfaces of extracted third molars (n = 28) were subjected only to grinding with a 600-grit SiC paper for 1 min (sound dentin S, n = 14) or additionally to erosive pH cycling with a cola-based soft-drink (eroded dentin E, n = 14). After acid etching, rinsing, and air drying, S and E were rehydrated with 1.5 μl of 2% CHX (S2%, n = 7; E2%, n = 7) or of distilled water (control SC, n = 7; EC, n = 7). Composite buildups were incrementally constructed with Filtek Z350 following Adper Single Bond 2 application. Specimens were sectioned into beams, which were subjected to microtensile testing immediately or after 6 or 12 months of aging. Fractured surfaces were observed under a digital microscope (50X magnification). Microtensile bond strength (μTBS) (MPa) was analyzed by three-way ANOVA and Tukey's tests (α = 0.05) and failure mode by the Kruskal-Wallis test (α = 0.05).
  
  
  RESULTS
  Compared to sound dentin, eroded dentin was consistently related to lower μTBS. Immediately and after 12-month aging, the effect of CHX was insignificant, but it was significant after 6-month aging, when it conserved the bond strength to both eroded and sound dentin. The percentage of adhesive and mixed failures were equivalent, and significantly more frequent than cohesive failures, whether in dentin or in composite.
  
  
  CONCLUSIONS
  The 2% CHX effect on bond strength conservation to both eroded and sound dentin was not found to be persistent.
authors.forename: Luciana Fávaro
authors.initials: LF
authors.lastname: Francisconi-dos-Rios
authors.forename: Leslie Caroll
authors.initials: LC
authors.lastname: Casas-Apayco
authors.forename: Marcela Pagani
authors.initials: MP
authors.lastname: Calabria
authors.forename: Paulo Afonso Silveria
authors.initials: PA
authors.lastname: Francisconi
authors.forename: Ana Flávia Sanches
authors.initials: AF
authors.lastname: Borges
authors.forename: Linda
authors.initials: L
authors.lastname: Wang
mesh_terms: D000134:Acid Etching, Dental / Q000379:methods; D000891:Anti-Infective Agents, Local / Q000737:chemistry*; D017554:Carbon Compounds, Inorganic / Q000737:chemistry; D002253:Carbonated Beverages / Q000009:adverse effects; D002710:Chlorhexidine / Q000031:analogs & derivatives* / Q000737:chemistry; D003188:Composite Resins / Q000737:chemistry; D001840:Dental Bonding; D003738:Dental Cements / Q000737:chemistry; D045662:Dental Etching / Q000379:methods; D003764:Dental Materials / Q000737:chemistry; D003799:Dental Stress Analysis / Q000295:instrumentation; D003804:Dentin / Q000648:ultrastructure*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D018613:Microscopy, Confocal; D009067:Mouthwashes / Q000737:chemistry*; D010756:Phosphoric Acids / Q000737:chemistry; D012464:Saliva, Artificial / Q000737:chemistry; D017655:Silicon Compounds / Q000737:chemistry; D013499:Surface Properties; D013718:Tensile Strength; D013997:Time Factors; D014077:Tooth Erosion / Q000473:pathology*; D014867:Water / Q000737:chemistry
chemical_list: C554641:Adper single bond 2; D000891:Anti-Infective Agents, Local; D017554:Carbon Compounds, Inorganic; D003188:Composite Resins; D003738:Dental Cements; D003764:Dental Materials; D009067:Mouthwashes; D010756:Phosphoric Acids; D012464:Saliva, Artificial; D017655:Silicon Compounds; C533204:filtek Z350; D014867:Water; C030242:phosphoric acid; C010882:chlorhexidine gluconate; D002710:Chlorhexidine; C022088:silicon carbide