title: Evaluation of the efficacy of flowable composite as lining material on microleakage of composite resin restorations: A systematic review and meta-analysis.
abstract: OBJECTIVE
  The efficacy of flowable composite in improving marginal adaptation or reducing microleakage is not fully understood. The purpose of this study was to systematically evaluate existing evidence to verify whether an application of flowable composite as a liner provided less microleakage in Class 2 composite restorations.
  
  
  METHODS
  PubMed, ISI (Web of Science), and Scopus databases were searched according to the selected keywords, up to 15 Feb 2015, without any restriction on date or language. Full texts of published articles that seemed to meet primary criteria for inclusion in this research were obtained. Data of studies were extracted if they were assessed as high or moderate level of evidence. Due to the variation of methods used in different studies, they were divided into five groups: groups 1 and 2, studies that evaluated the effect of flowable composite as a liner on dentinal or enamel margins and applied flowable composite on all of the cavity wall margins; groups 3 and 4, studies that evaluated the effect of flowable composite as a liner on dentinal and enamel margins and applied flowable composite only on gingival margin; and group 5, clinical studies.
  
  
  RESULTS
  The initial search yielded 1,370 publications. After hand searching, six extra studies were included in the review. The abstracts of all were read independently by AB and SG. After methodologic assessment and evaluation of the level of evidence, 18 studies were selected for this study. The results of this study indicate that flowable composite liners have no significant effect on microleakage of composite restorations in all of five groups.
  
  
  CONCLUSIONS
  Application of flowable composite as a liner in composite restorations cannot reduce microleakage or improve clinical performance.
authors.forename: Alireza
authors.initials: A
authors.lastname: Boruziniat
authors.forename: Samineh
authors.initials: S
authors.lastname: Gharaee
authors.forename: Alireza
authors.initials: A
authors.lastname: Sarraf Shirazi
authors.forename: Sara
authors.initials: S
authors.lastname: Majidinia
authors.forename: Mehdi
authors.initials: M
authors.lastname: Vatanpour
mesh_terms: D003188:Composite Resins / Q000627:therapeutic use*; D003736:Dental Cavity Lining / Q000379:methods*; D003737:Dental Cavity Preparation; D003763:Dental Leakage / Q000517:prevention & control*; D018772:Dental Marginal Adaptation; D003793:Dental Restoration, Permanent; D006801:Humans
chemical_list: D003188:Composite Resins; C111840:flowable hybrid composite