title: Effect of 2% chlorhexidine on dentin microtensile bond strengths and nanoleakage of luting cements.
abstract: OBJECTIVE
  The aim of this study was to investigate the effect of pre-treatment by chlorhexidine on the microtensile bond strength (mTBS) of resin cements and nanoleakage at the resin-dentine interfaces.
  
  
  METHODS
  Cylindrical composite blocks were luted to human dentine using resin cements (RelyX ARC, 3M ESPE: ARC; Panavia F, Kuraray Medical Inc.: PF; RelyX Unicem, 3M ESPE: UN) with/without pre-treatment by 2% chlorhexidine digluconate (CAVITY CLEANSER, Bisco, Inc., Schaumburg, IL, USA). CAVITY CLEANSER was applied on the acid etched dentine for 60s in the ARC group, and on smear layer-covered dentine in the PF and UN groups. After storage in water for 24h, the bonded teeth were sectioned into 1mm thick slabs and further into 0.9mm x 0.9mm beams. After immersion in water or ammoniacal silver nitrate for 24h, the beams were stressed to failure in tension. The fractured surfaces were examined by field-emission scanning electron microscopy (FE-SEM) using backscattered electron mode. The silver-stained slabs were used to examine nanoleakage within the bonded interface by FE-SEM.
  
  
  RESULTS
  The resin cement and chlorhexidine treatment had significant effects (p<0.0001) on mTBS; while the storage media had no significant effect (p=0.435). The mTBS of ARC was significantly higher than the other cements. Chlorhexidine reduced mTBS and produced pronounced nanoleakage when PF and UC were luted to dentine.
  
  
  CONCLUSIONS
  Pre-treatment with chlorhexidine affected the integrity of dentine bonding with PF and UC, while there was no adverse effect on coupling of ARC.
authors.affiliation: Paediatric Dentistry and Orthodontics, The University of Hong Kong, Prince Philip Dental Hospital, 34 Hospital Road, Pokfulam, Hong Kong SAR, China. hiraishinoriko@yahoo.com
authors.forename: N
authors.initials: N
authors.lastname: Hiraishi
authors.forename: C K Y
authors.initials: CK
authors.lastname: Yiu
authors.forename: N M
authors.initials: NM
authors.lastname: King
authors.forename: F R
authors.initials: FR
authors.lastname: Tay
mesh_terms: D000134:Acid Etching, Dental; D000891:Anti-Infective Agents, Local / Q000737:chemistry*; D017438:Bisphenol A-Glycidyl Methacrylate / Q000737:chemistry; D002710:Chlorhexidine / Q000031:analogs & derivatives* / Q000737:chemistry; D003188:Composite Resins / Q000737:chemistry; D001840:Dental Bonding; D003763:Dental Leakage / Q000145:classification*; D003804:Dentin / Q000648:ultrastructure*; D006801:Humans; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D011092:Polyethylene Glycols / Q000737:chemistry; D011109:Polymethacrylic Acids / Q000737:chemistry; D019279:Resin Cements / Q000737:chemistry*; D012835:Silver Nitrate / Q000737:chemistry; D016622:Silver Staining; D016369:Smear Layer; D013314:Stress, Mechanical; D013499:Surface Properties; D013718:Tensile Strength; D013997:Time Factors; D014867:Water / Q000737:chemistry
chemical_list: D000891:Anti-Infective Agents, Local; D003188:Composite Resins; C438843:Panavia-Fluoro; D011109:Polymethacrylic Acids; C483701:Rely X Unicem; C462240:RelyX ARC; D019279:Resin Cements; D014867:Water; D011092:Polyethylene Glycols; D017438:Bisphenol A-Glycidyl Methacrylate; D012835:Silver Nitrate; C010882:chlorhexidine gluconate; D002710:Chlorhexidine