title: Effect of chlorhexidine on initial adhesion of fiber-reinforced post to root canal.
abstract: OBJECTIVE
  Chlorhexidine is used as final irrigant before endodontic obturation and fiber-reinforced composite posts are recommended for restoration retention. Our aim was to evaluate the effect of chlorhexidine on adhesion of cements used in post cementation. We hypothesized that chlorhexidine would not negatively affect the immediate bond strength.
  
  
  METHODS
  Root canals of eighty human extracted third molars were prepared for post cementation with each post systems' own burs. Four commercially available FRC posts (Glassix, D.T.Light-Post, Unicore, everStickPOST) with three cements (Duo-link with All-bond 2, PermaFlo DC with PermaFlo DC Primers, RelyX Unicem) were used. After etching, except with self-etching RelyX Unicem, the post spaces were irrigated either with 2% chlorhexidine (Consepsis) or physiological saline for 60 s. With RelyX Unicem, respective treatments were done before cement application. The roots (n=5 per group) were cut into 2 mm thick dentin discs. The bond strength was measured with push-out method, and the failure mode was evaluated with a stereomicroscope.
  
  
  RESULTS
  Significant differences in bond strength were observed between various post/cement combinations. Unicore/PermaFlo DC and everStickPOST/RelyX Unicem showed significantly higher bond strengths than Glassix or D.T.Light-Post with Duo-link both with saline and chlorhexidine. Chlorhexidine improved the bond strength slightly with all posts/cements except with D.T.Light-Post, but the differences were not statistically significant. With chlorhexidine, significant reduction of adhesive failures towards dentin cohesive or mixed failures was observed with all posts/cements except with everStickPOST.
  
  
  CONCLUSIONS
  Chlorhexidine did not negatively affect the push-out bond strength in post bond cementation.
authors.affiliation: City of Helsinki Health Centre, University of Helsinki, Helsinki University Hospital (HUC), Helsinki, Finland. ritva.lindblad@pp.inet.fi
authors.forename: Ritva M
authors.initials: RM
authors.lastname: Lindblad
authors.forename: Lippo V J
authors.initials: LV
authors.lastname: Lassila
authors.forename: Veijo
authors.initials: V
authors.lastname: Salo
authors.forename: Pekka K
authors.initials: PK
authors.lastname: Vallittu
authors.forename: Leo
authors.initials: L
authors.lastname: Tjäderhane
mesh_terms: D000134:Acid Etching, Dental / Q000379:methods; D002710:Chlorhexidine / Q000737:chemistry*; D003188:Composite Resins / Q000737:chemistry; D001840:Dental Bonding; D003738:Dental Cements / Q000737:chemistry*; D003764:Dental Materials / Q000737:chemistry*; D017267:Dental Prosthesis Design; D003786:Dental Pulp Cavity / Q000473:pathology*; D003799:Dental Stress Analysis / Q000295:instrumentation; D003804:Dentin / Q000648:ultrastructure; D004853:Epoxy Resins / Q000737:chemistry; D005898:Glass / Q000737:chemistry; D006801:Humans; D008422:Materials Testing; D008689:Methacrylates / Q000737:chemistry; D011176:Post and Core Technique / Q000295:instrumentation*; D011791:Quartz / Q000737:chemistry; D019279:Resin Cements / Q000737:chemistry; D012388:Root Canal Irrigants / Q000737:chemistry*; D012464:Saliva, Artificial / Q000737:chemistry; D013314:Stress, Mechanical; D013696:Temperature; D013997:Time Factors
chemical_list: D003188:Composite Resins; D003738:Dental Cements; D003764:Dental Materials; C431350:Duo-Link; D004853:Epoxy Resins; D008689:Methacrylates; C423507:PermaFlow; C483701:Rely X Unicem; D019279:Resin Cements; D012388:Root Canal Irrigants; D012464:Saliva, Artificial; C496140:everStick; C009753:fiberglass; D011791:Quartz; C100742:All-Bond 2; D002710:Chlorhexidine