title: Microshear bond strength of self-etching adhesives to caries-affected dentin identified using the dye permeability test.
abstract: OBJECTIVE
  The aim of this study was to compare microshear bond strength (µSBS) of different adhesives to normal dentin (ND) and caries-affected dentin (AD) as differentiated using the dye permeability test.
  
  
  METHODS
  One hundred freshly extracted carious teeth were ground to expose normal and cariesaffected dentin. Differentiation between both substrates was carried out using microhardness and a new dye permeability method. Ground teeth were divided into 5 groups according to the adhesive tested; Clearfil SE Bond (SE), Clearfil DC Bond (DC) (Kuraray), Bond Force (BF) (Tokuyama), AdheseOne (AH) (Ivoclar), Adper Prompt-L-pop (PR) (3M ESPE). Adhesives were applied to selected substrate, and composite cylinders (0.9 mm diameter x 0.7 mm length) were formed. After 24 h, specimens were subjected to microshear testing at a crosshead speed of 0.5 mm/min. Failure modes were determined using a stereomicroscope at 40X magnification. Data were analyzed using Kruskal-Wallis and Mann-Whitney U-tests.
  
  
  RESULTS
  Normal dentin was permeable for the dye, while caries-affected dentin was impermeable. Vickers hardness numbers (VHN) for normal and caries-affected dentin were 63.98 ± 3.24 and 62.40 ± 3.49 respectively, which were not significantly different (p > 0.05). µSBS values were: SE-ND = 22.34 ± 6.4, SE-AD = 18.70 ± 4.0, BF-ND = 24.52 ± 4.9, BF-AD = 18.31 ± 4.9, DC-ND = 24.49 ± 8.0, DC-AD = 18.97 ± 9.4, AH-ND = 17.21 ± 6.8, AH-AD = 17.03 ± 10.3, PR-ND = 13.67 ± 4.4, PR-AD = 7.31 ± 2.4 MPa. A statistically significant difference was found among the adhesive systems to both normal (p < 0.01) and caries-affected dentin (p < 0.001). However, µSBS of SE, DC, and AH adhesives to normal dentin were not significantly different from those of caries-affected dentin (p > 0.05).
  
  
  CONCLUSIONS
  The permeability test was an effective tool to differentiate between normal and caries-affected dentin. Some adhesive systems showed no significant difference in their bond to normal or affected dentin.
authors.affiliation: Department of Restorative Dentistry, Faculty of Oral and Dental Medicine, Cairo University, Cairo Egypt. enasmobarak@hotmail.com
authors.forename: Enas H
authors.initials: EH
authors.lastname: Mobarak
authors.forename: Wafa H
authors.initials: WH
authors.lastname: El-Badrawy
mesh_terms: D000134:Acid Etching, Dental / Q000379:methods; D004396:Coloring Agents; D001840:Dental Bonding; D003731:Dental Caries / Q000175:diagnosis / Q000473:pathology; D003799:Dental Stress Analysis; D003804:Dentin / Q000473:pathology; D003806:Dentin Permeability; D017220:Dentin-Bonding Agents; D006244:Hardness; D006801:Humans; D008422:Materials Testing; D008751:Methylene Blue; D019279:Resin Cements; D033081:Shear Strength; D018709:Statistics, Nonparametric
chemical_list: D004396:Coloring Agents; D017220:Dentin-Bonding Agents; D019279:Resin Cements; D008751:Methylene Blue