title: The effect of dentine surface preparation and reduced application time of adhesive on bonding strength.
abstract: OBJECTIVE
  This study evaluated the effects of surface preparation and the application time of adhesives on the resin-dentine bond strengths with universal adhesives.
  
  
  METHODS
  Sixty molars were cut to exposed mid-coronal dentine and divided into 12 groups (n=5) based on three factors; (1) adhesive: G-Premio Bond (GP, GC Corp., Tokyo, Japan), Clearfil Universal Bond (CU, Kuraray Noritake Dental Inc., Okayama, Japan) and Scotchbond Universal Adhesive (SB, 3M ESPE, St. Paul, MN, USA); (2) smear layer preparation: SiC paper ground dentine or bur-cut dentine; (3) application time: shortened time or as manufacturer's instruction. Fifteen resin-dentine sticks per group were processed for microtensile bond strength test (μTBS) according to non-trimming technique (1mm(2)) after storage in distilled water (37 °C) for 24h. Data were analyzed by three-way ANOVA and Dunnett T3 tests (α=0.05). Fractured surfaces were observed under scanning electron microscope (SEM). Another 12 teeth were prepared and cut into slices for SEM examination of bonded interfaces.
  
  
  RESULTS
  μTBS were higher when bonded to SiC-ground dentine according to manufacturer's instruction. Bonding to bur-cut dentine resulted in significantly lower μTBS (p<0.000). Shortening the application time resulted in significantly lower bond strength for CU on SiC and GP on bur-cut dentine. SEM of fractured surfaces revealed areas with a large amount of porosities at the adhesive resin interface. This was more pronounced when adhesives were bonded with a reduced application time and on bur cut dentine.
  
  
  CONCLUSIONS
  The performance of universal adhesives can be compromised on bur cut dentine and when applied with a reduced application time.
authors: Department of Restorative Dentistry, Division of Oral Health Science, Hokkaido University Graduate School of Dental Medicine, Kita 13, Nishi 7, Kita-ku, Sapporo 060-8586, Japan. Electronic address: pipop045@den.hokudai.ac.th.
authors: Pipop
authors: P
authors: Saikaew
authors: Department of Restorative Dentistry, Division of Oral Health Science, Hokkaido University Graduate School of Dental Medicine, Kita 13, Nishi 7, Kita-ku, Sapporo 060-8586, Japan.
authors: A F M Almas
authors: AF
authors: Chowdhury
authors: Department of Restorative Dentistry, Division of Oral Health Science, Hokkaido University Graduate School of Dental Medicine, Kita 13, Nishi 7, Kita-ku, Sapporo 060-8586, Japan.
authors: Mai
authors: M
authors: Fukuyama
authors: Department of Restorative Dentistry, Division of Oral Health Science, Hokkaido University Graduate School of Dental Medicine, Kita 13, Nishi 7, Kita-ku, Sapporo 060-8586, Japan.
authors: Shinichi
authors: S
authors: Kakuda
authors: Department of Restorative Dentistry, Division of Oral Health Science, Hokkaido University Graduate School of Dental Medicine, Kita 13, Nishi 7, Kita-ku, Sapporo 060-8586, Japan; Department of Oral Biological and Medical Sciences, Division of Biomaterials, University of British Columbia, Faculty of Dentistry, 2199 Wesbrook Mall, Vancouver, BC V6T 1Z3, Canada.
authors: Ricardo M
authors: RM
authors: Carvalho
authors: Department of Restorative Dentistry, Division of Oral Health Science, Hokkaido University Graduate School of Dental Medicine, Kita 13, Nishi 7, Kita-ku, Sapporo 060-8586, Japan.
authors: Hidehiko
authors: H
authors: Sano
mesh_terms: D000134:Acid Etching, Dental / Q000379:methods; D000269:Adhesives; D001840:Dental Bonding / Q000379:methods*; D003754:Dental High-Speed Equipment; D003799:Dental Stress Analysis; D003804:Dentin / Q000737:chemistry* / Q000187:drug effects; D017220:Dentin-Bonding Agents / Q000737:chemistry* / Q000494:pharmacology; D006801:Humans; D008964:Molar, Third / Q000187:drug effects / Q000648:ultrastructure; D011897:Random Allocation; D016369:Smear Layer / Q000737:chemistry; D013499:Surface Properties; D014082:Tooth Fractures / Q000628:therapy; D019246:Tooth Preparation / Q000379:methods*
chemical_list: D000269:Adhesives; D017220:Dentin-Bonding Agents
keywords: Bonding application time; Microtensile bond strength; SEM; Surface preparation; Universal adhesives