title: Weak evidence suggests higher risk for bracket bonding failure with self-etch primer compared to conventional acid etch over 12 months.
abstract: METHODS
  Medline, Embase, Cochrane Oral Health Group's Trials Register and the Cochrane Central Register of Controlled Trials (CENTRAL). Unpublished data were sought by searching ClinicalTrials.gov, the National Research Register and Pro-Quest Dissertation Abstracts and Thesis database. There were no language restrictions.
  
  
  METHODS
  Randomised and controlled clinical trials (including split mouth) directly comparing self-etch and acid-etch primers including patients with full-arch, fixed and bonded orthodontic appliances (not banded) with follow-up periods of at least 12 months were included.
  
  
  METHODS
  Two authors abstracted data independently, with disagreements being resolved by a third. The Cochrane Risk of Bias tool was used to assess study quality. A random effects meta-analysis was undertaken.
  
  
  RESULTS
  Eleven studies were included in the qualitative summary with five studies contributing to a meta-analysis. These five studies (n =3444 brackets, 1721 acid-etch, 1723 self-etch) had relatively low statistical and clinical heterogeneity. Meta-analysis demonstrated a tendency for a higher risk of failure (odds ratio 1.35; 95% CI, 0.99-1.83; P 5 0.06) with self-etch primers. The use of self-etch techniques was also associated with a small but statistically significant time saving (weighted mean difference 23.2 seconds per bracket; 95% CI, 20.7-25.8; P \0.001). There was insufficient evidence to assess the effect of bonding modality on demineralisation rates.
  
  
  CONCLUSIONS
  There is weak evidence indicating higher odds of failure with self-etch primer than acid-etch over 12 months in orthodontic patients, and there is strong evidence that a self-etch primer is likely to result in modest time savings (eight minutes for full bonding) compared with acid-etch.
authors.affiliation: Evidence Based Dentistry Centre, Faculty of Oral and Dental Medicine, Cairo University.
authors.forename: Ahmed
authors.initials: A
authors.lastname: Elkhadem
authors.forename: Noha
authors.initials: N
authors.lastname: Orabi
mesh_terms: D000134:Acid Etching, Dental / Q000379:methods*; D001840:Dental Bonding / Q000379:methods*; D003738:Dental Cements / Q000737:chemistry*; D006801:Humans; D009967:Orthodontic Appliances
chemical_list: D003738:Dental Cements