title: Comparative evaluation of self-etching primers with fourth and fifth generation dentin-bonding systems on carious and normal dentin substrates: An in vitro shear bond strength analysis.
abstract: OBJECTIVE
  The aim of this study was to test the hypothesis that bonding to caries-affected dentin would yield strengths that are lower than bond strengths achievable when bonded to normal dentin. Dentin-bonding systems used in this study were fourth and fifth generation as well as self-etching primers.
  
  
  METHODS
  Forty-eight freshly extracted mandibular and maxillary molars were selected of which 24 were caries-affected teeth and the remaining were noncarious teeth. Random sampling was done with eight teeth in each group based on the bonding system used. In caries-affected teeth, the soft, stainable, caries-infected dentin was excavated using a caries detector dye whereas the hard, caries-affected, nonstainable dentin was retained. All the teeth were subsequently mounted in a suitable acrylic mould. Prepared teeth were restored with a single composite resin, using three different dentin bonding systems. These prepared specimens were transferred to a Hounsfield tensometer to measure the shear bond strength. The results obtained were analyzed using Anova, Student's unpaired t-test, and Student Neuman Keulis test.
  
  
  RESULTS
  The results showed that the self-etching primer required the highest mean shear load compared to the fifth and fourth generation dentin-bonding systems in both normal dentin and caries-affected dentin.
  
  
  CONCLUSIONS
  Bond strength to dentin depends on whether the dentinal tubule is open or occluded. Within the limitations of this study, it was observed that bond strength to caries-affected dentin was low compared to normal dentin.
authors.affiliation: Department of Conservative Dentistry and Endodontics, K. L. E. V. K. Institute of Dental Sciences, J. N. M. C. Campus, Nehrunagar, Belgaum - 590 010, Karnataka, India.
authors.forename: Ramesh H
authors.initials: RH
authors.lastname: Giriyappa
authors.forename: B Suresh
authors.initials: BS
authors.lastname: Chandra