title: Effect of the application time of phosphoric acid and self-etch adhesive systems to sclerotic dentin.
abstract: OBJECTIVE
  To evaluate the effect of application time on the resin-dentin bond strength (µTBS) and etching pattern of adhesive systems applied on sclerotic dentine.
  
  
  METHODS
  A total of forty-two bovine incisors had their roots removed. The 1-step self-etch GO (SDI), the 2-step self-etch Adper SE Bond (3MESPE) and the 35% phosphoric acid (3MESPE) from the 2-step etch-and-rinse Adper Single Bond 2 (3MESPE) were applied on the bovine incisal surfaces according to the manufacturer's instructions or duplicating the recommended conditioning time. After adhesive application, thirty teeth were restored with composite resin, stored for 24 h in distilled water at 37°C, and sectioned into resin-dentin bonded sticks (0.8 mm²) and tested according to the µTBS at 0.5 mm/min. The etching pattern of the remaining twelve teeth (n=4 for each material) was examined under scanning electron microscopy. Each tooth was divided into a buccal-to-lingual direction into three thirds, and each third randomly assigned to the groups: control (no treatment), according to the manufacturers' instructions and duplicating the recommended application time. The µTBS and the relative percentage of the tubule area opening were evaluated by two-way repeated measures ANOVA and Tukey's tests (α=0.05).
  
  
  RESULTS
  The duplication of the conditioning time favored only the GO adhesive (p<0.05). Both application methods significantly increased the tubule area opening (p<0.05) compared to the controls.
  
  
  CONCLUSIONS
  The efficacy of duplicating the conditioning time was only effective for the 1-step self-etch adhesive system tested.
authors.affiliation: School of Dentistry, Department of Restorative Dentistry, State University of Ponta Grossa, Ponta Grossa, PR, Brazil.
authors.forename: Alexandra Patricia
authors.initials: AP
authors.lastname: Mena-Serrano
authors.forename: Eugenio Jose
authors.initials: EJ
authors.lastname: Garcia
authors.forename: Miguel Muñoz
authors.initials: MM
authors.lastname: Perez
authors.forename: Gislaine Cristine
authors.initials: GC
authors.lastname: Martins
authors.forename: Rosa Helena Miranda
authors.initials: RH
authors.lastname: Grande
authors.forename: Alessandro Dourado
authors.initials: AD
authors.lastname: Loguercio
authors.forename: Alessandra
authors.initials: A
authors.lastname: Reis
mesh_terms: D000134:Acid Etching, Dental / Q000379:methods*; D000818:Animals; D002417:Cattle; D001840:Dental Bonding / Q000379:methods*; D003738:Dental Cements / Q000737:chemistry; D003804:Dentin / Q000737:chemistry / Q000187:drug effects*; D017220:Dentin-Bonding Agents / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D010756:Phosphoric Acids / Q000737:chemistry*; D011897:Random Allocation; D013499:Surface Properties / Q000187:drug effects; D013718:Tensile Strength; D013997:Time Factors
chemical_list: C554641:Adper single bond 2; D003738:Dental Cements; D017220:Dentin-Bonding Agents; D010756:Phosphoric Acids; C030242:phosphoric acid