title: Bond failure rates with a self-etching primer: a randomized controlled trial.
abstract: BACKGROUND
  The purpose of this clinical trial was to evaluate over a 12-month period the performance of a self-etching system (SEP) (Transbond Plus SEP, 3M Unitek, Monrovia, Calif) compared with a conventional multi-step system (TBXT) (Transbond XT, 3M Unitek).
  
  
  METHODS
  Twenty-eight randomly selected patients were included in this study. They were randomly assigned to either the TBXT or the SEP group. A total of 548 brackets were bonded according to the manufacturer's instructions with Transbond XT adhesive paste (3M Unitek). The survival rates of brackets were estimated with the Kaplan-Meier analysis. Bracket survival distributions for bonding procedure, tooth location, dental arch, and patient sex were compared with the log-rank test.
  
  
  RESULTS
  The failure rates of the TBXT and SEP groups were 4.78% and 6.88%, respectively. No significant differences in the survival rates were observed between the bonding procedures (P = 0.311). When tooth location, dental arch, and sex were analyzed, only tooth location was significant. Posterior brackets were more likely to fail than anterior brackets (P = 0.013).
  
  
  CONCLUSIONS
  Both systems had low bond failure rates and are adequate for orthodontic bonding needs.
authors.affiliation: Department of Orthodontics, Fluminense Federal University, Nova Friburgo, Rio de Janeiro, Brazil. juliocalneto@yahoo.com.br
authors.forename: Julio Pedra e
authors.initials: JP
authors.lastname: Cal-Neto
authors.forename: Cátia Abdo
authors.initials: CA
authors.lastname: Quintão
authors.forename: Marco Antônio de Oliveira
authors.initials: MA
authors.lastname: Almeida
authors.forename: José Augusto Mendes
authors.initials: JA
authors.lastname: Miguel
mesh_terms: D000293:Adolescent; D002648:Child; D003724:Dental Arch; D001840:Dental Bonding; D004868:Equipment Failure; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008334:Mandible; D008422:Materials Testing; D008437:Maxilla; D016910:Orthodontic Brackets; D019279:Resin Cements / Q000737:chemistry*; D012737:Sex Factors; D013314:Stress, Mechanical; D016019:Survival Analysis; D014070:Tooth
chemical_list: D019279:Resin Cements; C429625:Transbond Plus Self-Etching Primer; C477790:Transbond XT