title: A randomized clinical trial comparing 'one-step' and 'two-step' orthodontic bonding systems.
abstract: OBJECTIVE
  The primary objective of this prospective clinical trial was to assess the clinical bond failure rates of orthodontic brackets bonded using a self-etching primer (SEP), compared with brackets bonded using a conventional acid-etched technique with control adhesive (Transbond). A secondary aim was to investigate whether characteristics of the operator, patient or tooth bonded had any influence on bracket failure.
  
  
  METHODS
  Single-centre randomized controlled clinical trial. Thirty-four patients were bonded, each being randomly assigned to either the test or control adhesive.
  
  
  METHODS
  NHS Hospital Orthodontic Department, Chester, UK.
  
  
  METHODS
  Orthodontic patients requiring fixed appliance treatment.
  
  
  METHODS
  Bond failure.
  
  
  RESULTS
  Failure rates over the initial 6-month period were 2.0% (Transbond) and 1.7% (SEP) with no statistically significant difference between the two groups. Over the duration of the fixed appliance treatment, bond failure rates increased, but remained acceptable at 7.4 % (TB) and 7.0% (SEP), respectively. When operator, patient and tooth characteristics were analysed, only the bracket location was found to be significant. Maxillary brackets were more likely to fail than mandibular brackets (RR 0.47%; 95% CI 0.22, 1.03). The failure rate for brackets in our study was low when compared with previous studies.
  
  
  CONCLUSIONS
  Both the acid-etched control and self-etching primer in combination with adhesive pre-coated brackets were successful for clinical bonding. Their combined failure rate was lower than that reported in similar trials.
authors.affiliation: Countess of Chester NHS Trust, Health Park, Liverpool Road, Chester CH2 1UL, UK.
authors.forename: N
authors.initials: N
authors.lastname: Manning
authors.forename: S M
authors.initials: SM
authors.lastname: Chadwick
authors.forename: D
authors.initials: D
authors.lastname: Plunkett
authors.forename: T V
authors.initials: TV
authors.lastname: Macfarlane
mesh_terms: D000134:Acid Etching, Dental; D000293:Adolescent; D002648:Child; D001840:Dental Bonding / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D016910:Orthodontic Brackets; D011446:Prospective Studies; D012044:Regression Analysis; D019279:Resin Cements
chemical_list: D019279:Resin Cements; C429625:Transbond Plus Self-Etching Primer; C477790:Transbond XT