title: Bonding performance of universal adhesives in different etching modes.
abstract: OBJECTIVE
  The aim of this study was to compare the microtensile bond strength (μTBS) and resin penetration into dentine of three universal adhesives (UAs) applied in two different etching modes (i.e. self-etch or etch-and-rinse). The effect of thermocycling on the μTBS was also evaluated.
  
  
  METHODS
  The occlusal third of sound human molars was removed and the exposed surfaces were treated with three UAs (Futurabond Universal, Scotchbond Universal Adhesive and All-Bond Universal) in self-etch or etch-and-rinse mode. Two one-step self-etch adhesives (Futurabond DC and Futurabond M) were applied on additional teeth as reference. After composite build up, the specimens were stored for 24 h in distilled water at 37 °C or thermocycled for 5000 cycles. Composite/dentine beams were prepared (1 mm(2)) and μTBS test was performed. Data was analyzed using three-way ANOVA and Tukey's test (α=0.05). One additional tooth was prepared for each group for evaluation of infiltration ability into dentine by dyeing the adhesives with a fluorochrome (Rhodamine B). After longitudinal sectioning, the generated interfaces were examined under confocal laser scanning microscopy.
  
  
  RESULTS
  The addition of an etching step did not significantly affect the μTBS of none of the UAs, when compared to their self-etch application mode. All pre-etched specimens showed considerably longer resin tags and thicker hybrid layers. Thermocycling had no significant effect on the μTBS of the UAs.
  
  
  CONCLUSIONS
  Application of an etching step prior to UAs improves their dentine penetration, but does not affect their bond strength to dentine after 24h or after thermocycling for 5000 cycles.
  
  
  CONCLUSIONS
  Similar bond strength values were observed for the UAs regardless of application mode, which makes them reliable for working under different clinical conditions.
authors.affiliation: Laboratory for Biomaterials Research, Dental Clinic 1 - Operative Dentistry and Periodontology, University of Erlangen-Nuernberg, Erlangen, Germany.
authors.forename: Andrea
authors.initials: A
authors.lastname: Wagner
authors.affiliation: Laboratory for Biomaterials Research, Dental Clinic 1 - Operative Dentistry and Periodontology, University of Erlangen-Nuernberg, Erlangen, Germany; Department of Restorative Dentistry, Faculty of Dentistry, University of Concepción, Concepción, Chile.
authors.forename: Michael
authors.initials: M
authors.lastname: Wendler
authors.affiliation: Laboratory for Biomaterials Research, Dental Clinic 1 - Operative Dentistry and Periodontology, University of Erlangen-Nuernberg, Erlangen, Germany.
authors.forename: Anselm
authors.initials: A
authors.lastname: Petschelt
authors.affiliation: Laboratory for Biomaterials Research, Dental Clinic 1 - Operative Dentistry and Periodontology, University of Erlangen-Nuernberg, Erlangen, Germany.
authors.forename: Renan
authors.initials: R
authors.lastname: Belli
authors.affiliation: Laboratory for Biomaterials Research, Dental Clinic 1 - Operative Dentistry and Periodontology, University of Erlangen-Nuernberg, Erlangen, Germany. Electronic address: ulrich.lohbauer@fau.de.
authors.forename: Ulrich
authors.initials: U
authors.lastname: Lohbauer
mesh_terms: D000134:Acid Etching, Dental / Q000379:methods*; D003188:Composite Resins / Q000737:chemistry; D001840:Dental Bonding; D003764:Dental Materials / Q000737:chemistry; D003804:Dentin / Q000648:ultrastructure; D005456:Fluorescent Dyes; D006801:Humans; D055115:Light-Curing of Dental Adhesives / Q000379:methods; D008422:Materials Testing; D008689:Methacrylates / Q000737:chemistry; D018613:Microscopy, Confocal / Q000379:methods; D011897:Random Allocation; D019279:Resin Cements / Q000737:chemistry*; D012235:Rhodamines; D013314:Stress, Mechanical; D013499:Surface Properties; D013696:Temperature; D013718:Tensile Strength; D013997:Time Factors; D014867:Water / Q000737:chemistry
chemical_list: C074864:All-Bond system; D003188:Composite Resins; D003764:Dental Materials; D005456:Fluorescent Dyes; D008689:Methacrylates; D019279:Resin Cements; D012235:Rhodamines; D014867:Water; C041330:Scotchbond; C029773:rhodamine B
keywords: Adhesion; Dentine bonding; Etch-and-rinse; Self-etch; Universal adhesives