title: Efficacy of hydrophobic layer on sealing ability of dentin adhesive systems in class v composite resin restorations.
abstract: OBJECTIVE
  Adhesive permeability is hindered by application of an additional layer of hydrophobic resin, which increases its concentration within the hydrophilic layer, reduces its affinity to water, and enhances its physical prop-erties. The aim of the present study was to evaluate the effect of a hydrophobic layer on the microleakage of class V composite restorations using different adhesives.
  
  
  METHODS
  The adhesives including total-etch Scotchbond MP and Single Bond, and the self-etch Clearfil SE Bond and Clearfil S3 Bond were applied to 80 class V cavities in vitro on the buccal surface in CEJ and then were fol-lowed by hydrophobic resin (Margin Bond) in half of the cavities in each group (n=10). After restoration with microhybrid composite, Z100 and immersion in fuchsine, the degree of microleakage was assessed. Data were analyzed using the Krus-kal-Wallis, Man-Whitney, and Wilcoxon tests.
  
  
  RESULTS
  The hydrophobic layer significantly reduced the microleakage of Clearfil SE Bond and Clearfil S3 Bond only in dentin (p<0.05). There was no significant difference between enamel and dentinal margins in Clearfil S3 Bond, Clearfil SE Bond plus Margin Bond, and Clearfil S3 Bond plus Margin Bond (p>0.05).
  
  
  CONCLUSIONS
  Within the limitation of this study, only Clearfil S3 Bond could demonstrate the identical values of microle-akage in enamel and dentinal margins.
authors.affiliation: Associate Professor, Department of Operative Dentistry, School of Dentistry, Mashhad University of Medical Sciences, Mashhad, Iran.
authors.forename: Fatemeh
authors.initials: F
authors.lastname: Maleknejad
authors.forename: Saied Mostafa
authors.initials: SM
authors.lastname: Moazzami
authors.forename: Elham
authors.initials: E
authors.lastname: Baradaran Nasseri
authors.forename: Ehsan
authors.initials: E
authors.lastname: Baradaran Nasseri