title: The risk of bias of animal experiments in implant dentistry: a methodological study.
abstract: OBJECTIVE
  To evaluate the risk of bias (ROB) in reports of randomised controlled trials (RCTs) of animal experiments published in implant dentistry, and to explore the association between animal experiment characteristics and ROB.
  
  
  METHODS
  We searched the MEDLINE (via PubMed), SCOPUS and SciELO databases from 2010 to March 2015 for reports of RCTs of animal experiments published in implant dentistry. We evaluated independently and in duplicate the ROB of these experiments by the use of a tool specifically developed to evaluate ROB in animal studies, the SYRCLE's tool. ROB was judged as low, high or unclear (when there was not enough information to judge ROB). We used univariate and multivariate logistic regression analyses to evaluate the association of specific study characteristics and extent of ROB.
  
  
  RESULTS
  We initially selected 850 publications and 161 reports of animal experiments were included. For a total of 1449 entries (records), 486 (34%) were rated as low ROB. High ROB was attributed to 80 (6%) of entries, and 883 (60%) entries were rated as unclear ROB. The characteristics "impact factor" (IF), reporting of standard error (SE) and reporting of confidence interval (CI) were significantly associated with low ROB in some SYRCLE domains.
  
  
  CONCLUSIONS
  A substantial number of items with unclear ROB were observed in this sample of animal experiments in implant dentistry. Furthermore, the present findings suggest that implant dentistry animal experiments published in journals with higher IF and better report of measures of precision; that is, CI and SE may have lower ROB than those not having these characteristics.
authors.affiliation: Department of Periodontology and Operative Dentistry, Faculty of Dentistry, University of Münster, Münster, Germany.
authors.forename: Clovis Mariano
authors.initials: CM
authors.lastname: Faggion
authors.affiliation: Academic Department of Clinical Stomatology, Section of Integral Oral Implantology, Cayetano Heredia Peruvian University, Lima, Perú.
authors.forename: Karla Tatiana
authors.initials: KT
authors.lastname: Diaz
authors.affiliation: Academic Department of Clinical Stomatology, Section of Periodontology and Implants, Cayetano Heredia Peruvian University, Lima, Perú.
authors.forename: Luisiana
authors.initials: L
authors.lastname: Aranda
authors.affiliation: Department of Conservative Dentistry, Heidelberg University, Heidelberg, Germany.
authors.forename: Frank
authors.initials: F
authors.lastname: Gabel
authors.affiliation: Department of Conservative Dentistry, Heidelberg University, Heidelberg, Germany.|Max Planck Institute for Social Law and Social Policy, Munich Center for the Economics of Aging, Munich, Germany.
authors.forename: Stefan
authors.initials: S
authors.lastname: Listl
authors.affiliation: Academic Department of Clinical Stomatology, Section of Periodontology and Implants, Cayetano Heredia Peruvian University, Lima, Perú.
authors.forename: Marco Antonio
authors.initials: MA
authors.lastname: Alarcón
mesh_terms: D032761:Animal Experimentation; D000818:Animals; D015982:Bias; D003813:Dentistry; D016032:Randomized Controlled Trials as Topic; D012306:Risk
keywords: SYRCLE's tool; animal experimentation; methods; risk of bias; treatment effect