title: SEM analysis of hybrid layer and bonding interface after chlorhexidine use.
abstract: OBJECTIVE
  To evaluate the appearance of the hybrid layer of one total-etch and one self-etch bonding agent on human teeth with and with-out the application of 2% chlorhexidine after water storage.
  
  
  METHODS
  Twelve human maxillary teeth (molars and premolars) had two Class II cavities (MO-OD) prepared. Teeth were separated in two groups (n=6) to receive either Adper Single Bond 2 or Adper SE Plus (3MESPE). In one cavity, the dentin donding agent was applied following manufacturer's instructions. On the adjacent cavity, 2% chlorhexidine was applied for 30 seconds before the application of the bonding agent. Teeth were sectioned mesiodistally with a slow-speed diamond disk and stored in water at 37°C for four months. The teeth were prepared for scanning electron microscope observation.The appearance of the hybrid layer was ob-served and measured by two variables: clear image of hybrid layer and presence of resintags in tubules. Data were analyzed with a Kruskal-Wallis test calculated at a 0.05 significance level.
  
  
  RESULTS
  All groups treated with chlorhexidine had the clear presence of a hybrid layer,whereas only half the specimens without chlorhexidine had a clear hybrid layer. Chlorhexidine did not affect the presence of resin tags.
  
  
  CONCLUSIONS
  The use of 2% chlorhexidine be-fore the application of a dentin-bonding agent reduced the deterioration of the hybrid layer when exposed to water.
authors.affiliation: Department of Restorative Sciences, University of Costa Rica, Costa Rica.
authors.forename: D
authors.initials: D
authors.lastname: Lafuente
mesh_terms: D000134:Acid Etching, Dental / Q000379:methods; D001641:Bicuspid / Q000473:pathology; D002710:Chlorhexidine / Q000737:chemistry*; D003188:Composite Resins / Q000737:chemistry; D003737:Dental Cavity Preparation / Q000145:classification; D003738:Dental Cements / Q000737:chemistry; D003804:Dentin / Q000648:ultrastructure*; D017220:Dentin-Bonding Agents / Q000737:chemistry*; D006801:Humans; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D008963:Molar / Q000473:pathology; D010756:Phosphoric Acids / Q000737:chemistry; D013499:Surface Properties; D013696:Temperature; D013997:Time Factors; D014867:Water / Q000737:chemistry
chemical_list: C554641:Adper single bond 2; D003188:Composite Resins; D003738:Dental Cements; D017220:Dentin-Bonding Agents; C474035:Filtek Supreme; D010756:Phosphoric Acids; D014867:Water; C030242:phosphoric acid; D002710:Chlorhexidine