title: Effect of a chlorhexidine-containing adhesive on dentin bond strength stability.
abstract: OBJECTIVE
  The present study aimed to investigate a novel adhesive system containing 0.2% chlorhexidine digluconate (CHX) for its ability to improve the stability of the adhesive interface compared with the use of 2% CHX as a therapeutic primer. Furthermore, the study aimed to confirm the inhibitory properties of these CHX concentrations (0.2% and 2.0%) on dentin matrix metalloproteinase activity by gelatin zymography.
  
  
  METHODS
  Superficial dentin substrate for bonding was obtained from 120 non-carious human molars. A conventional adhesive Peak LC Bond and a CHX-containing adhesive Peak Universal Bond were used either in combination with 35% phosphoric acid (etch-and-rinse approach) or with self-etching primer (self-etch approach) for evaluation of the variables CHX treatment (2.0% therapeutic primer and 0.2% adhesive), adhesive approach (etch-and-rinse and self-etch), and storage time (24 hours and six months). A bonding jig was used to fabricate composite cylinders, which were stored for either 24 hours or six months, after which shear bond strength (SBS) was evaluated using a notched-edge testing device. A three-way analysis of variance and a Student t-test with a significance level of p<0.05 were used to analyze the data. Extracts from concentrated demineralized human dentin powder were subjected to sodium dodecyl sulfate polyacrylamide gel electrophoresis and incubated in the presence of 0.2% and 2.0% CHX.
  
  
  RESULTS
  No significant effect of CHX treatment, adhesive approach, storage time variables, or their interactions on mean SBS was demonstrated (p<0.05). No significant difference between the control and the CHX-treated groups was detected for either adhesive technique at 24 hours or six months (p<0.05). No significant variation in mean SBS was detected after six months of storage (p<0.05). Zymographic analysis revealed bands of enzymatic activity for the group demineralized with phosphoric acid and complete inhibition of gelatinolytic activity for the groups treated with 0.2% and 2.0% CHX.
  
  
  CONCLUSIONS
  CHX demonstrated inhibition of dentin proteolytic activity. However, when CHX was incorporated into a commercially available adhesive or used as a therapeutic primer, no difference in bond strength was observed at baseline or after six months of storage relative to the control group without CHX.
authors.forename: C
authors.initials: C
authors.lastname: Sabatini
mesh_terms: D002710:Chlorhexidine / Q000031:analogs & derivatives* / Q000627:therapeutic use; D001840:Dental Bonding / Q000379:methods*; D003738:Dental Cements / Q000627:therapeutic use*; D045662:Dental Etching / Q000379:methods; D003799:Dental Stress Analysis; D003804:Dentin / Q000378:metabolism; D006801:Humans; D008963:Molar
chemical_list: D003738:Dental Cements; C010882:chlorhexidine gluconate; D002710:Chlorhexidine