title: Periodontal health during clear aligners treatment: a systematic review.
abstract: BACKGROUND
  Clear aligner treatment (CAT) has been cited as a safe and comfortable orthodontic procedure for adult patients. However, the available evidence is scarce.
  
  
  OBJECTIVE
  To perform a systematic review of the existing literature in order to assess periodontal health during CAT.
  
  
  METHODS
  Pubmed, Pubmed Central, National Library of Medicine's Medline, Embase, Cochrane Central Register of Controlled Clinical trials, Web of Knowledge, Scopus, Google Scholar, and LILACS were searched from January 1945 to September 2014 to identify all peer-reviewed papers potentially relevant to the review.
  
  
  METHODS
  After duplicate selection and extraction procedures, the risk of bias was assessed according to the Centre for Reviews and Dissemination criteria, and a 3-point grading system, as described by the Swedish Council on Technology Assessment in Health Care (SBU), was used to rate the methodological quality of the selected papers. A PICOS table was used for data extraction.
  
  
  RESULTS
  Five relevant articles were selected from the 1247 identified articles. The level of evidence was moderate for all the studies. A significant improvement of the periodontal health indexes was revealed, in particular when CAT was compared to fixed appliances. No periodontal CAT adverse effects were observed in the selected studies.
  
  
  CONCLUSIONS
  Periodontal health indexes were significantly improved during CAT. The results of this review should be interpreted with some caution because of the number, quality, and heterogeneity of the included studies.
authors.affiliation: Department of Orthodontics, Dental School, University of Turin, Italy dr.gabriele.rossini@gmail.com.
authors.forename: Gabriele
authors.initials: G
authors.lastname: Rossini
authors.affiliation: Department of Orthodontics, Dental School, University of Turin, Italy.
authors.forename: Simone
authors.initials: S
authors.lastname: Parrini
authors.affiliation: Department of Orthodontics, Dental School, University of Turin, Italy.
authors.forename: Tommaso
authors.initials: T
authors.lastname: Castroflorio
authors.affiliation: Department of Orthodontics, Dental School, University of Turin, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Deregibus
authors.affiliation: Department of Orthodontics, Dental School, University of Turin, Italy.
authors.forename: Cesare L
authors.initials: CL
authors.lastname: Debernardi
mesh_terms: D015982:Bias; D057189:Checklist; D006801:Humans; D016382:Orthodontic Appliance Design; D010512:Periodontal Index; D014087:Tooth Movement Techniques / Q000295:instrumentation / Q000379:methods*