title: Influence of 2% chlorhexidine digluconate on bond strength of a glass-fibre post luted with resin or glass-ionomer based cement.
abstract: OBJECTIVE
  This study evaluated the influence of 2% chlorhexidine digluconate (CHX) on the bond strength (BS) of a glass-fibre post to the root canal, regarding the cements (dual-cured resin or resin-modified glass-ionomer cement), the root thirds and the time of storage.
  
  
  METHODS
  Eighty bovine roots were selected and endodontically treated, before being randomly assigned to the following groups according to the luting protocol: ARC (RelyX ARC); ARC+CHX; RL (RelyX Luting 2); and RL+CHX. After 24 h of luting, the roots were sliced to obtain 1 mm-thick slices. Half of each group was submitted to either 7-day or 6-month storage in artificial saliva (n=10). The specimens were subjected to push-out tests with a crosshead speed of 0.5 mm/min. The data were analysed with four-way ANOVA and Tukey's test (P≤0.05). The failure modes were analysed with a digital microscope (50× and 200×).
  
  
  RESULTS
  ARC yielded a significantly higher BS compared to RL (P<0.001). Despite CHX exerted a significant effect; it depends on the interaction with the luting cement and time (P<0.001). Thus, CHX decreased the values of BS to those of ARC after 6 months (P<0.001). On the 7th day of storage, the ARC+CHX presented higher BS to the cervical and middle thirds compared to RL+CHX (P=0.012). Time solely was not a significant factor (P=0.081). Adhesive cement-dentine type and mixed failures were predominant modes for the ARC groups. For the RL groups, the main failures were adhesive cement-post and mixed modes.
  
  
  CONCLUSIONS
  Glass-fibre posts luted with RelyX ARC dual-cure resin cement exhibited higher BS than those luted with RelyX Luting 2 resin-modified glass-ionomer cement. Furthermore, CHX was not effective to improve the BS and negatively affected the BS of RelyX ARC after 6 months of storage.
  
  
  CONCLUSIONS
  The use of chlorhexidine solution seems not to improve the bond strength of fibre posts to root canals, disregarding the composition of the luting cement.
authors.affiliation: Department of Operative Dentistry, Endodontics and Dental Materials, Bauru School of Dentistry, University of São Paulo, Bauru, SP, Brazil.
authors.forename: Diana Ferreira Gadelha
authors.initials: DF
authors.lastname: de Araújo
authors.affiliation: Department of Operative Dentistry, Endodontics and Dental Materials, Bauru School of Dentistry, University of São Paulo, Bauru, SP, Brazil.
authors.forename: Larissa Pinceli
authors.initials: LP
authors.lastname: Chaves
authors.affiliation: Department of Operative Dentistry, Endodontics and Dental Materials, Bauru School of Dentistry, University of São Paulo, Bauru, SP, Brazil.
authors.forename: Odair
authors.initials: O
authors.lastname: Bim
authors.affiliation: Department of Restorative Dentistry, Dental Materials Area, University of Brasília-UnB, DF, Brazil.
authors.forename: Fernanda Cristina
authors.initials: FC
authors.lastname: Pimentel Garcia
authors.affiliation: Department of Operative Dentistry, Endodontics and Dental Materials, Bauru School of Dentistry, University of São Paulo, Bauru, SP, Brazil.
authors.forename: Sérgio Kiyoshi
authors.initials: SK
authors.lastname: Ishikiriama
authors.affiliation: Department of Pediatric Dentistry, Orthodontics and Collective Health, Bauru School of Dentistry, University of São Paulo, Bauru, SP, Brazil.
authors.forename: Heitor Marques
authors.initials: HM
authors.lastname: Honório
authors.affiliation: Department of Operative Dentistry, Endodontics and Dental Materials, Bauru School of Dentistry, University of São Paulo, Bauru, SP, Brazil. Electronic address: wang.linda@usp.br.
authors.forename: Linda
authors.initials: L
authors.lastname: Wang
mesh_terms: D000818:Animals; D017438:Bisphenol A-Glycidyl Methacrylate / Q000737:chemistry; D002417:Cattle; D002710:Chlorhexidine / Q000031:analogs & derivatives* / Q000737:chemistry; D003188:Composite Resins / Q000737:chemistry; D001840:Dental Bonding; D003764:Dental Materials / Q000737:chemistry*; D003786:Dental Pulp Cavity / Q000648:ultrastructure*; D003804:Dentin / Q000648:ultrastructure; D004791:Enzyme Inhibitors / Q000737:chemistry*; D005898:Glass / Q000737:chemistry*; D005899:Glass Ionomer Cements / Q000737:chemistry*; D008422:Materials Testing; 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*; D018915:Root Canal Preparation / Q000379:methods; D012464:Saliva, Artificial / Q000737:chemistry; D055116:Self-Curing of Dental Resins; D013314:Stress, Mechanical; D013499:Surface Properties; D013997:Time Factors; D019227:Tooth Apex / Q000648:ultrastructure
chemical_list: D003188:Composite Resins; D003764:Dental Materials; D004791:Enzyme Inhibitors; D005899:Glass Ionomer Cements; D011109:Polymethacrylic Acids; C462240:RelyX ARC; D019279:Resin Cements; D012464:Saliva, Artificial; C084550:Vitremer; C009753:fiberglass; D011092:Polyethylene Glycols; D017438:Bisphenol A-Glycidyl Methacrylate; C010882:chlorhexidine gluconate; D002710:Chlorhexidine
keywords: Bond strength; Chlorhexidine; Dual-cure resin cement; Resin-modified glass-ionomer cement; Root canal