title: Microtensile bond strength of two-step etch-and-rinse adhesive systems on sound and artificial caries-affected dentin.
abstract: OBJECTIVE
  To evaluate the microtensile bond strength of two-step etch-and-rinse adhesive systems on sound and artificial caries-affected dentin (CAD) produced by in vitro monoculture of Streptococcus mutans.
  
  
  METHODS
  10 recently extracted non-carious human third molars were ground to expose a flat dentin surface. Each tooth was sectioned through the long axis with a diamond saw to create two similar halves. One half was used as control (sound dentin - SD) while the other was submitted to caries lesion induction in vitro, using 40 mL of Brain Heart Infusion broth containing 1% sucrose and 40 microL of Streptococcus mutans UA159 inoculum (final bacterial concentration: 1-2 x 105 CFU/mL). The specimens were incubated at 37 degrees C for 4 weeks, and the culture medium was changed every 3 days for 4 weeks. Sound or CAD were alternatively restored as follow (n = 5): Single Bond 2/sound dentin (SB-SD); Single Bond 2/artificial caries-affected dentin (SB-CAD); Prime&Bond NT/sound dentin (PB-SD); and Prime&Bond NT/CAD (PB-CAD).The adhesives were applied to dentin according to manufacturers' instructions, and build-ups of resin composite (Filtek Z250) were prepared and polymerized with a LED light-curing unit (Radii). The restored teeth were stored in distilled water at 37 degrees C for 24 hours and thereafter sectioned perpendicular to the bonded interface with a refrigerated low-speed diamond saw, obtaining three slices per half-tooth (n = 15). The microtensile bond strength (microTBS) test was performed in a universal test machine with a crosshead speed of 1 mm/minute. Bond strengths were calculated in MPa and analyzed by Kruskal-Wallis and Student-Newman-Keuls at a 0.05 level of significance. Failure patterns were examined with an optical microscope.
  
  
  RESULTS
  SD produced significantly higher microTBS values than CAD for both adhesive systems. Furthermore, independently of the dentin condition, Single Bond 2 had higher values than Prime Bond NT (P < 0.05). Single Bond 2 showed higher microTBS than Prime Bond NT, in both substrates, and application to CAD reduced the adhesion.
authors: Department of Operative Dentistry, Federal University of Pelotas, School of Dentistry, Rio Grande do Sul, Brazil.
authors: César Henrique
authors: CH
authors: Zanchi
authors: Rafael Guerra
authors: RG
authors: Lund
authors: Luciana Rodrigues
authors: LR
authors: Perrone
authors: Gládis Aver
authors: GA
authors: Ribeiro
authors: Francisco Augusto Burkert
authors: FA
authors: del Pino
authors: Márcia Bueno
authors: MB
authors: Pinto
authors: Flávio Fernando
authors: FF
authors: Demarco
mesh_terms: D000096:Acetone; D000134:Acid Etching, Dental; D017438:Bisphenol A-Glycidyl Methacrylate; D001840:Dental Bonding; D003731:Dental Caries; D003799:Dental Stress Analysis; D003804:Dentin; D017220:Dentin-Bonding Agents; D000431:Ethanol; D006801:Humans; D008422:Materials Testing; D011109:Polymethacrylic Acids; D019279:Resin Cements / Q000737:chemistry; D013718:Tensile Strength
chemical_list: D017220:Dentin-Bonding Agents; D011109:Polymethacrylic Acids; C425843:Prime and Bond NT; D019279:Resin Cements; C115612:single bond; D000096:Acetone; D000431:Ethanol; D017438:Bisphenol A-Glycidyl Methacrylate