title: A comparative clinical study of the failure rate of orthodontic brackets bonded with two adhesive systems: conventional and self-etching primer (SEP).
abstract: OBJECTIVE
  This study compared the clinical performance of orthodontic brackets bonded with Transbond adhesive paste after two primer systems: a two-stage conventional system (acid etching + Transbond XT adhesive primer) and a single-stage self-etching primer (SEP) (Transbond Plus).
  
  
  METHODS
  The sample comprised 480 metal brackets bonded to the teeth of 24 consecutive patients treated for 36 to 48 months. A split-mouth design was used for bonding, and both systems were used in each patient. Bracket failure rates for each system were analyzed; and failure causes as reported by the patients and the quadrant of teeth for which brackets failed were recorded.
  
  
  RESULTS
  The conventional system group had a failure rate of 5.41%, whereas the rate for SEP was 4.58%. In this group, there were 5 failures (38.4%) in the right maxillary quadrant, 2 (15.4%) in the left maxillary quadrant, 4 (30.8%) in the right mandibular quadrant, and 2 (15.4%) in the left mandibular quadrant. In the SEP group, there were 4 (36.4%) failures in the right maxillary quadrant, 1 (9%) in the left maxillary quadrant, 3 (27.3%) in the right mandibular quadrant, and 3 (27.3%) in the left mandibular quadrant. Results of descriptive statistical analysis and odds ratio did not show any significant differences between rates (p = 0.67).
  
  
  CONCLUSIONS
  The clinical efficiency of SEP was similar to that of the conventional system.
authors.affiliation: Department of Orthodontics and Pediatric Dentistry, School of Dentistry, São Paulo University (FOUSP), São Paulo, Brazil.
authors.forename: Gladys Cristina
authors.initials: GC
authors.lastname: Dominguez
authors.forename: André
authors.initials: A
authors.lastname: Tortamano
authors.forename: Luiz Vicente de Moura
authors.initials: LV
authors.lastname: Lopes
authors.forename: Priscilla Campanatti Chibebe
authors.initials: PC
authors.lastname: Catharino
authors.forename: Camillo
authors.initials: C
authors.lastname: Morea
mesh_terms: D000134:Acid Etching, Dental / Q000379:methods*; D017438:Bisphenol A-Glycidyl Methacrylate / Q000737:chemistry*; D001840:Dental Bonding / Q000379:methods*; D003799:Dental Stress Analysis; D019544:Equipment Failure Analysis; D006801:Humans; D008422:Materials Testing; D016017:Odds Ratio; D016910:Orthodontic Brackets; D019279:Resin Cements / Q000737:chemistry*
chemical_list: D019279:Resin Cements; C477790:Transbond XT; C065742:Transbond; D017438:Bisphenol A-Glycidyl Methacrylate
keywords: Bonding; Dental adhesive; Orthodontic brackets