title: Influence of chlorhexidine application time on the bond strength between fiber posts and dentin.
abstract: BACKGROUND
  The aim of this study was to investigate the effects of chlorhexidine (CHX) application time on the bond strength and durability of the adhesion of fiber posts relined with resin composite to the root dentin.
  
  
  METHODS
  Eighty bovine incisor roots were divided into 4 groups after root preparation: control group (irrigation with physiological solution) and experimental groups, CHX for 30 seconds, CHX for 60 seconds, and CHX for 120 seconds. Fiber posts relined with resin composite were cemented with RelyX ARC. The Scotchbond Multi-Purpose total-etching adhesive system was used in half of the samples of each group, and the Clearfil SE Bond self-etching adhesive system was used in the other half. The samples were randomly divided into 2 subgroups, 24 hours of storage and 12 months of storage. All roots were sectioned transversely, and push-out tests were performed. Bond strength means were analyzed by analysis of variance and Tukey test (α = 0.05). Failure mode was determined by examining specimen's surfaces under scanning electron microscope, and its distribution was evaluated by using χ(2) test (α = 0.05).
  
  
  RESULTS
  CHX pretreatment resulted in homogeneous bond strength values at 24 hours and 12 months of storage, irrespective of the CHX application time and adhesive system (P < .05). A significant bond strength decrease was noticed after 12 months of storage when irrigation was performed with physiological solution in the control groups (P > .05). Significant differences were observed for fracture patterns (P < .001).
  
  
  CONCLUSIONS
  The use of CHX pretreatment could preserve the bond strength of the fiber post relined with resin composite to root dentin for 12 months, irrespective of the CHX application time and adhesive system used.
authors.affiliation: Department of Restorative Dentistry, College of Dentistry, University of Passo Fundo, Passo Fundo, Rio Grande do Sul, Brazil. Electronic address: dgscecchin@yahoo.com.br.
authors.forename: Doglas
authors.initials: D
authors.lastname: Cecchin
authors.affiliation: Department of Restorative Dentistry, College of Dentistry, University of Passo Fundo, Passo Fundo, Rio Grande do Sul, Brazil.
authors.forename: Ana Paula
authors.initials: AP
authors.lastname: Farina
authors.affiliation: Department of Restorative Dentistry, College of Dentistry, University of Passo Fundo, Passo Fundo, Rio Grande do Sul, Brazil.
authors.forename: Mateus
authors.initials: M
authors.lastname: Giacomin
authors.affiliation: Department of Restorative Dentistry, College of Dentistry, University of Illinois at Chicago, Chicago, Illinois.
authors.forename: Cristina de Mattos Pimenta
authors.initials: Cde M
authors.lastname: Vidal
authors.affiliation: Department of Restorative Dentistry, College of Dentistry, University of Passo Fundo, Passo Fundo, Rio Grande do Sul, Brazil.
authors.forename: Bruno
authors.initials: B
authors.lastname: Carlini-Júnior
authors.affiliation: Department of Restorative Dentistry, Piracicaba Dental School, State University of Campinas, Piracicaba, São Paulo, Brazil.
authors.forename: Caio Cezar Randi
authors.initials: CC
authors.lastname: Ferraz
mesh_terms: D000818:Animals; D017438:Bisphenol A-Glycidyl Methacrylate / Q000737:chemistry; D002417:Cattle; D002710:Chlorhexidine / Q000008:administration & dosage* / Q000737:chemistry; D003188:Composite Resins / Q000737:chemistry; D001840:Dental Bonding; D003764:Dental Materials / Q000737:chemistry; D003804:Dentin / Q000648:ultrastructure*; D005898:Glass / Q000737:chemistry; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D011092:Polyethylene Glycols / Q000737:chemistry; D011109:Polymethacrylic Acids / Q000737:chemistry; D011176:Post and Core Technique / Q000295:instrumentation*; D011897:Random Allocation; D019279:Resin Cements / Q000737:chemistry; D012388:Root Canal Irrigants / Q000008:administration & dosage* / Q000737:chemistry; D013314:Stress, Mechanical; D013499:Surface Properties; D013997:Time Factors
chemical_list: C438313:Clearfil SE Bond; D003188:Composite Resins; D003764:Dental Materials; C444701:Filtek Z250; D011109:Polymethacrylic Acids; C462240:RelyX ARC; D019279:Resin Cements; D012388:Root Canal Irrigants; C084018:Scotchbond Multi-Purpose; C009753:fiberglass; D011092:Polyethylene Glycols; D017438:Bisphenol A-Glycidyl Methacrylate; D002710:Chlorhexidine
keywords: Application time; bond strength; chlorhexidine; durability; fiber post; root canal