title: [Effect of casein phosphopeptide-amorphouscalcium phosphate (CPP-ACP) treatment on the shear bond strength of orthodontic brackets after tooth bleaching].
abstract: OBJECTIVE
  To evaluate the effect of casein phosphopeptide-amorphouscalcium phosphate (CPP-ACP) treatment on the shear bond strength of orthodontic brackets after tooth bleaching.
  
  
  METHODS
  One hundred extracted human premolars were randomly divided and treated according to 5 groups (n=20) : (1) no treatment; (2) 10% carbamide peroxide bleaching; (3) 38% hydrogen peroxide bleaching; (4)10% carbamide peroxide bleaching and CPP-ACP paste; (5)38% hydrogen peroxide bleaching and CPP-ACP paste. In all groups, the brackets were bonded using a conventional acid-etch and bond system (Transbond XT, 3M Unitek, Monrovia, Calif). The shear bond strength adhesive remnant index (ARI) of the brackets were determined and the data was analyzed by ANOVA and Bonferroni test using SPSS13.0 software package.
  
  
  RESULTS
  The use of 10% carbamide peroxide and 38% hydrogen peroxide bleaching significantly decreased the shear bond strength of orthodontic brackets when compared with untreated group (P<0.05). After combination of tooth bleaching and CPP-ACP treatment, group 4 (10% carbamide peroxide bleaching + CPP-ACP) and group 5 (38% hydrogen peroxide bleaching + CPP-ACP) showed higher levels of shear bond strength than group 2 and 3; however, no significant difference was found (P>0.05). The ARI did not show any significant difference before and after CPP-ACP treatment.
  
  
  CONCLUSIONS
  After tooth bleaching, CPP-ACP treatment have little influence on the shear bond strength of orthodontic brackets.
authors.affiliation: Department of Orthodontics, Shanghai Ninth People's Hospital, College of Stomatology, Shanghai Jiao Tong University School of Medicine; Shanghai Key Laboratory of Stomatology. Shanghai 200011.China.E-mail:lujing_7344@aliyun.com.
authors.forename: Jing
authors.initials: J
authors.lastname: Lu
authors.forename: Xiao-jun
authors.initials: XJ
authors.lastname: Ding
authors.forename: Xiao-ping
authors.initials: XP
authors.lastname: Yu
authors.forename: Yi-ming
authors.initials: YM
authors.lastname: Gong
mesh_terms: D000134:Acid Etching, Dental; D000077463:Carbamide Peroxide; D002364:Caseins / Q000627:therapeutic use*; D001840:Dental Bonding; D003743:Dental Enamel; D006801:Humans; D016910:Orthodontic Brackets; D010545:Peroxides; D010710:Phosphates; D010748:Phosphopeptides; D019279:Resin Cements; D033081:Shear Strength; D014073:Tooth Bleaching; D014508:Urea / Q000031:analogs & derivatives
chemical_list: D002364:Caseins; D010545:Peroxides; D010710:Phosphates; D010748:Phosphopeptides; D019279:Resin Cements; C477790:Transbond XT; C447032:casein phosphopeptide-amorphous calcium phosphate nanocomplex; D000077463:Carbamide Peroxide; D014508:Urea