title: Randomized controlled trials in dentistry: common pitfalls and how to avoid them.
abstract: OBJECTIVE
  Clinical trials are used to appraise the effectiveness of clinical interventions throughout medicine and dentistry. Randomized controlled trials (RCTs) are established as the optimal primary design and are published with increasing frequency within the biomedical sciences, including dentistry. This review outlines common pitfalls associated with the conduct of randomized controlled trials in dentistry.
  
  
  METHODS
  Common failings in RCT design leading to various types of bias including selection, performance, detection and attrition bias are discussed in this review. Moreover, methods of minimizing and eliminating bias are presented to ensure that maximal benefit is derived from RCTs within dentistry.
  
  
  CONCLUSIONS
  Well-designed RCTs have both upstream and downstream uses acting as a template for development and populating systematic reviews to permit more precise estimates of treatment efficacy and effectiveness. However, there is increasing awareness of waste in clinical research, whereby resource-intensive studies fail to provide a commensurate level of scientific evidence. Waste may stem either from inappropriate design or from inadequate reporting of RCTs; the importance of robust conduct of RCTs within dentistry is clear.
  
  
  CONCLUSIONS
  Optimal reporting of randomized controlled trials within dentistry is necessary to ensure that trials are reliable and valid. Common shortcomings leading to important forms or bias are discussed and approaches to minimizing these issues are outlined.
authors.affiliation: Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London E1 2AD, United Kingdom. Electronic address: padhraig.fleming@gmail.com.
authors.forename: Padhraig S
authors.initials: PS
authors.lastname: Fleming
authors.affiliation: Learning & Scholarship, School of Dentistry, Cardiff University, United Kingdom.
authors.forename: Christopher D
authors.initials: CD
authors.lastname: Lynch
authors.affiliation: Department of Orthodontics and Dentofacial Orthopedics, Dental School/Medical Faculty, University of Bern, Bern, Switzerland.
authors.forename: Nikolaos
authors.initials: N
authors.lastname: Pandis
mesh_terms: D015982:Bias; D018865:Dental Research / Q000592:standards*; D006801:Humans; D017594:Publication Bias; D016032:Randomized Controlled Trials as Topic / Q000592:standards*; D015203:Reproducibility of Results; D012196:Review Literature as Topic; D015983:Selection Bias
keywords: Clinical trial; Conduct; Dentistry; Randomized; Reporting