title: Initial shear bond strength of orthodontic brackets bonded to bleached teeth with a self-etching adhesive system.
abstract: OBJECTIVE
  To examine the initial shear bond strength of orthodontic brackets bonded to bleached teeth with a self-etching adhesive system, as well as the effect of the length of time after bleaching on the initial bond strength.
  
  
  METHODS
  Ninety premolars were collected and divided equally among a control group (CG) of unbleached teeth with brackets bonded, an immediate group (IG) with teeth bonded soon after bleaching, and a delayed group (DG) consisting of teeth bleached and then immersed in artificial saliva for 7 days before bracket bonding. Subsequently, the teeth of each group were equally assigned to two different primer adhesive systems: the acid-etch-and-rinse adhesive system (35% phosphoric acid gel and Transbond XT primer) and the self-etching adhesive system (Transbond Plus self-etching primer). Initial bond strength was measured 24 hours after bracket bonding.
  
  
  RESULTS
  IG registered the lowest mean initial bond strength when the self-etching adhesive system was in use, followed by DG and CG (in that order). As for the acid-etch-and-rinse adhesive system, the mean initial bond strength was significantly lower in IG than in CG and DG. Significant differences in mean initial bond strength were noted between the two adhesive systems in IG and DG.
  
  
  CONCLUSIONS
  In trials using a self-etching adhesive system, the mean initial bond strength that declined immediately after bleaching returned to a clinically acceptable level of 6 MPa after the specimens were immersed in artificial saliva for 7 days but fell short of the level of unbleached teeth.
authors.affiliation: Orthodontic Dentistry, The Nippon Dental University Niigata Hospital, Japan.
authors.forename: Rieko
authors.initials: R
authors.lastname: Ozoe
authors.forename: Toshiya
authors.initials: T
authors.lastname: Endo
authors.forename: Ryota
authors.initials: R
authors.lastname: Abe
authors.forename: Koichi
authors.initials: K
authors.lastname: Shinkai
authors.forename: Yoshiroh
authors.initials: Y
authors.lastname: Katoh
mesh_terms: D000134:Acid Etching, Dental / Q000379:methods; D001641:Bicuspid / Q000648:ultrastructure; D003188:Composite Resins / Q000737:chemistry; D001840:Dental Bonding; D003743:Dental Enamel / Q000648:ultrastructure; D003799:Dental Stress Analysis / Q000295:instrumentation; D006801:Humans; D006861:Hydrogen Peroxide / Q000737:chemistry; D008422:Materials Testing; D016910:Orthodontic Brackets; D010756:Phosphoric Acids / Q000737:chemistry; D019279:Resin Cements / Q000737:chemistry*; D012464:Saliva, Artificial / Q000737:chemistry; D033081:Shear Strength; D013314:Stress, Mechanical; D013696:Temperature; D013997:Time Factors; D014073:Tooth Bleaching / Q000379:methods*; D058205:Tooth Bleaching Agents / Q000737:chemistry*
chemical_list: D003188:Composite Resins; D010756:Phosphoric Acids; D019279:Resin Cements; D012464:Saliva, Artificial; D058205:Tooth Bleaching Agents; C429625:Transbond Plus Self-Etching Primer; C477790:Transbond XT; C516047:Transbond XT Light Cure Adhesive Primer; D006861:Hydrogen Peroxide; C030242:phosphoric acid