title: Optimal enamel conditioning strategy for rebonding orthodontic brackets: a laboratory study.
abstract: OBJECTIVE
  To compare the conventional etching and primer method (CEP) and the self-etching primer method (SEP) in rebonding brackets.
  
  
  METHODS
  Forty human maxillary second premolars extracted for orthodontic purpose were randomly divided into 4 equal groups. Group 1 and Group 2 were bonded using the CEP method; Group 3 and Group 4 using the SEP method. All the brackets were debonded and 40 new brackets were rebonded with four different protocols after surface cleaning: Group 1: CEP + adhesive; Group 2: CEP without etch step + adhesive; Group 3: SEP + adhesive; Group 4: non-acidic primer + adhesive. Then, the shear bond strength (SBS) of each group was tested and the measurements of adhesive remnant index scores (ARI) and SEM examination were performed.
  
  
  RESULTS
  The mean SBSs for Group 1, 2, 3 and 4 were 14.18, 6.57, 11.90, 5.91 MPa, respectively. Statistical differences of the SBS existed between Group 1 and 2 (P < 0.05) and between Group 3 and 4 (P < 0.05). No difference was found between Group 1 and 3, or Group 2 and 4.
  
  
  CONCLUSIONS
  Omission of the acid-etching step in rebonding orthodontic brackets may be adequate for the clinical requirement. No differences in SBS and ARI of the rebonded brackets were showed between CEP and SEP methods.
authors.affiliation: Department of Stomatology, The First Affiliated Hospital of Medical College, Zhejiang University Hangzhou, Zhejiang, China.
authors.forename: Qi-Feng
authors.initials: QF
authors.lastname: Zhang
authors.affiliation: Department of Stomatology, The First Affiliated Hospital of Medical College, Zhejiang University Hangzhou, Zhejiang, China.
authors.forename: Hua
authors.initials: H
authors.lastname: Yao
authors.affiliation: Department of Stomatology, The First Affiliated Hospital of Medical College, Zhejiang University Hangzhou, Zhejiang, China.
authors.forename: Zhi-Yong
authors.initials: ZY
authors.lastname: Li
authors.affiliation: Department of Stomatology, The First Affiliated Hospital of Medical College, Zhejiang University Hangzhou, Zhejiang, China.
authors.forename: Li
authors.initials: L
authors.lastname: Jin
authors.affiliation: Department of Stomatology, The First Affiliated Hospital of Medical College, Zhejiang University Hangzhou, Zhejiang, China.
authors.forename: Hui-Ming
authors.initials: HM
authors.lastname: Wang
keywords: Orthodontics; acid-etching; bond strength; dental bonding