title: Efficacy of clear aligners in controlling orthodontic tooth movement: a systematic review.
abstract: OBJECTIVE
  To assess the scientific evidence related to the efficacy of clear aligner treatment (CAT) in controlling orthodontic tooth movement.
  
  
  METHODS
  PubMed, PMC, NLM, Embase, Cochrane Central Register of Controlled Clinical Trials, Web of Knowledge, Scopus, Google Scholar, and LILACs were searched from January 2000 to June 2014 to identify all peer-reviewed articles potentially relevant to the review. Methodological shortcomings were highlighted and the quality of the studies was ranked using the Cochrane Tool for Risk of Bias Assessment.
  
  
  RESULTS
  Eleven relevant articles were selected (two Randomized Clinical Trials (RCT), five prospective non-randomized, four retrospective non-randomized), and the risk of bias was moderate for six studies and unclear for the others. The amount of mean intrusion reported was 0.72 mm. Extrusion was the most difficult movement to control (30% of accuracy), followed by rotation. Upper molar distalization revealed the highest predictability (88%) when a bodily movement of at least 1.5 mm was prescribed. A decrease of the Little's Index (mandibular arch: 5 mm; maxillary arch: 4 mm) was observed in aligning arches.
  
  
  CONCLUSIONS
  CAT aligns and levels the arches; it is effective in controlling anterior intrusion but not anterior extrusion; it is effective in controlling posterior buccolingual inclination but not anterior buccolingual inclination; it is effective in controlling upper molar bodily movements of about 1.5 mm; and it is not effective in controlling rotation of rounded teeth in particular. However, the results of this review should be interpreted with caution because of the number, quality, and heterogeneity of the studies.
authors.affiliation: a   Resident, Department of Orthodontics, Dental School, University of Turin, Turin, Italy.
authors.forename: Gabriele
authors.initials: G
authors.lastname: Rossini
authors.affiliation: a   Resident, Department of Orthodontics, Dental School, University of Turin, Turin, Italy.
authors.forename: Simone
authors.initials: S
authors.lastname: Parrini
authors.affiliation: b   Visiting Professor, Department of Orthodontics, Dental School, University of Turin, Turin, Italy.
authors.forename: Tommaso
authors.initials: T
authors.lastname: Castroflorio
authors.affiliation: c   Adjunct Professor, Department of Orthodontics, Dental School, University of Turin, Turin, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Deregibus
authors.affiliation: d   Professor and Department Chairman, Department of Orthodontics, Dental School, University of Turin, Turin, Italy.
authors.forename: Cesare L
authors.initials: CL
authors.lastname: Debernardi
mesh_terms: D006801:Humans; D008310:Malocclusion / Q000628:therapy*; D016382:Orthodontic Appliance Design / Q000295:instrumentation* / Q000379:methods; D011446:Prospective Studies; D012189:Retrospective Studies; D014087:Tooth Movement Techniques / Q000295:instrumentation* / Q000379:methods
keywords: Clear aligner therapy; Invisalign®; Invisible orthodontics; Orthodontics