title: Influence of chlorhexidine concentration on the durability of etch-and-rinse dentin bonds: a 12-month in vitro study.
abstract: OBJECTIVE
  To investigate the effect of 0.2% and 2% chlorhexidine (CHX) used as a therapeutic primer on the long-term bond strengths of two etch-and-rinse adhesive systems.
  
  
  METHODS
  Adper Scotchbond 1XT (SB1) and XP-Bond (XPB) were evaluated. Etched dentin substrates were assigned to 6 treatment groups: (1) 0.2% CHX + SB1; (2) 2% CHX + SB1; (3) SB1 (control); (4) 0.2% CHX + XPB; (5) 2% CHX + XPB; (6) XPB (control). Composite buildups were made and beams prepared for microtensile bond strength testing. Beams were divided into 3 subgroups and either immediately pulled to failure or stored in artificial saliva for 6 or 12 months prior to testing. Data were evaluated with three-way ANOVA. Additional adhesive interfaces were prepared to investigate nanoleakage expression by TEM.
  
  
  RESULTS
  SB1 and XPB showed similar immediate bond strength values with or without CHX pretreatment (p > 0.05). After 12 months, bonds fell from 43.9 +/- 9.5 MPa to 20.1 +/- 5.4 MPa and from 39.6 +/- 9.4 MPa to 14.2 +/- 5.0 MPa in control specimens for SB1 and XPB respectively, while bond fell only from 41.9 +/- 9.6MPa to 33.2 +/- 8.3 MPa and 38.3 +/- 8.9 MPa to 26.5 +/- 10.9 (for SB1 and XPB, respectively) when 0.2% CHX was previously used. CHX concentration did not affect bond strength values (0.2% vs 2%, p > 0.05). Nanoleakage increased during aging in controls, but reduced silver deposits were found in CHX-treated specimens.
  
  
  CONCLUSIONS
  Chlorhexidine significantly reduced the loss of bond strength seen in control bonds. Since no bacterial growth was present in the aging conditions, the results of this study suggest that endogenous factors thought to degrade the adhesive interface can be inhibited by CHX. Further in vivo trials should confirm the role of CHX in bond durability.
authors: Department of Biomedicine, Unit of Dental Sciences and Biomaterials, University of Trieste, Trieste, Italy. lbreschi@units.it
authors: Lorenzo
authors: L
authors: Breschi
authors: Federica
authors: F
authors: Cammelli
authors: Erika
authors: E
authors: Visintini
authors: Annalisa
authors: A
authors: Mazzoni
authors: Francesca
authors: F
authors: Vita
authors: Marcela
authors: M
authors: Carrilho
authors: Milena
authors: M
authors: Cadenaro
authors: Stephen
authors: S
authors: Foulger
authors: Giovanni
authors: G
authors: Mazzoti
authors: Franklin R
authors: FR
authors: Tay
authors: Roberto
authors: R
authors: Di Lenarda
authors: David
authors: D
authors: Pashley
mesh_terms: D000134:Acid Etching, Dental / Q000379:methods*; D002710:Chlorhexidine / Q000737:chemistry; D001840:Dental Bonding / Q000379:methods*; D003763:Dental Leakage; D003799:Dental Stress Analysis; D017220:Dentin-Bonding Agents / Q000737:chemistry; D006801:Humans; D008422:Materials Testing; D008964:Molar, Third; D011480:Protease Inhibitors / Q000737:chemistry; D013718:Tensile Strength
chemical_list: D017220:Dentin-Bonding Agents; D011480:Protease Inhibitors; C532387:XP-Bond; D002710:Chlorhexidine