title: Publication bias & small-study effects in pediatric dentistry meta-analyses.
abstract: OBJECTIVE
  The aim of this study was to examine the presence and extent of publication bias and small-study effects in meta-analyses (MAs) investigating pediatric dentistry-related subjects.
  
  
  METHODS
  Following a literature search, 46 MAs including 882 studies were analyzed qualitatively. Of these, 39 provided enough data to be re-analyzed. Publication bias was assessed with the following methods: contour-enhanced funnel plots, Begg and Mazumdar's rank correlation and Egger's linear regression tests, Rosenthal's failsafe N, and Duval and Tweedie's "trim and fill" procedure.
  
  
  RESULTS
  Only a few MAs adequately assessed the existence and effect of publication bias. Inspection of the funnel plots indicated asymmetry, which was confirmed by Begg-Mazumdar's test in 18% and by Egger's test in 33% of the MAs. According to Rosenthal's criterion, 80% of the MAs were robust, while adjusted effects with unpublished studies differed from little to great from the unadjusted ones. Pooling of the Egger's intercepts indicated that evidence of asymmetry was found in the pediatric dental literature, which was accentuated in dental journals and in diagnostic MAs. Since indications of small-study effects and publication bias in pediatric dentistry were found, the influence of small or missing trials on estimated treatment effects should be routinely assessed in future MAs.
authors: Department of Orthodontics, School of Dentistry, University of Bonn, Bonn, Germany; Department of Oral Technology, School of Dentistry, University of Bonn, Bonn, Germany; Clinical Research Unit 208, University of Bonn, Bonn, Germany. Electronic address: snpapage@gmail.com.
authors: Spyridon N
authors: SN
authors: Papageorgiou
authors: Department of Paediatric Dentistry, School of Dentistry, Aristotle University of Thessaloniki, Thessaloniki, Greece.
authors: Dionysia
authors: D
authors: Dimitraki
authors: Department of Oral Health Sciences, School of Dentistry, University of Washington, Seattle, WA, USA.
authors: Trilby
authors: T
authors: Coolidge
authors: Department of Paediatric Dentistry, School of Dentistry, Aristotle University of Thessaloniki, Thessaloniki, Greece.
authors: Nikolaos
authors: N
authors: Kotsanos
mesh_terms: D006801:Humans; D016014:Linear Models; D015201:Meta-Analysis as Topic; D015233:Models, Statistical; D016017:Odds Ratio; D010377:Pediatric Dentistry; D017594:Publication Bias; D012107:Research Design; D016896:Treatment Outcome
keywords: File-drawer problem; Funnel plot; Meta-analysis; Meta-analytical study; Pediatric dentistry; Publication bias