title: Orthodontic aligners and root resorption: A systematic review.
abstract: BACKGROUND
  Root resorption is one of the leading problems in orthodontic treatment. Most earlier studies have assessed the incidence and severity of root resorption following orthodontic treatment using fixed appliances as well as associated factors. However, few studies have assessed these parameters in the context of orthodontic treatment using thermoplastic splints or aligners. The aim of this systematic review was to assess the incidence and severity of root resorption following orthodontic treatment using aligners and associated factors. A comparative analysis was also made with fixed multi-bracket treatments.
  
  
  METHODS
  The data bases consulted were: Medline, Embase, EBSCO Host, Cochrane Library and Science Direct. Our search included meta-analyses, randomized and non-randomized controled trials, cohort studies and descriptive studies published before December 2015 and evidencing a connection with the incidence and severity of root resorption following orthodontic treatment using aligners alone or compared with fixed multi-bracket treatments.
  
  
  RESULTS
  Among the 93 selected references, only 3 studies met our selection criteria. The incidence of root resorption ranged between 0 and 46%, of which 6% were severe cases. Relative to fixed multi-bracket non-extraction treatments to correct the same malocclusions, the incidence of resorption ranged between 2% and 50%, of which 22% were severe cases. In both techniques, the incidence of resorption was higher for the maxillary incisors and was not influenced by either age or sex.
  
  
  CONCLUSIONS
  In malocclusion cases not requiring extractions, orthodontic aligner treatment is possibly associated with a lower incidence of resorption than fixed multi-bracket treatment. Further research encompassing extraction cases is needed to better assess the incidence and severity of root resorption following the use of these removable appliances.
authors.affiliation: Service d'orthopédie dento-faciale, faculté de médecine dentaire, Mohammed V University, avenue Allal el Fassi, rue Mohammed Jazouli, cité Al Irfane, BP 6212, Rabat, Morocco. Electronic address: rajae.elhaddaoui@gmail.com.
authors.forename: Rajae
authors.initials: R
authors.lastname: Elhaddaoui
authors.affiliation: Service d'orthopédie dento-faciale, faculté de médecine dentaire, Mohammed V University, avenue Allal el Fassi, rue Mohammed Jazouli, cité Al Irfane, BP 6212, Rabat, Morocco.
authors.forename: Halima Saadia
authors.initials: HS
authors.lastname: Qoraich
authors.affiliation: Service d'orthopédie dento-faciale, faculté de médecine dentaire, Mohammed V University, avenue Allal el Fassi, rue Mohammed Jazouli, cité Al Irfane, BP 6212, Rabat, Morocco.
authors.forename: Loubna
authors.initials: L
authors.lastname: Bahije
authors.affiliation: Service d'orthopédie dento-faciale, faculté de médecine dentaire, Mohammed V University, avenue Allal el Fassi, rue Mohammed Jazouli, cité Al Irfane, BP 6212, Rabat, Morocco.
authors.forename: Fatima
authors.initials: F
authors.lastname: Zaoui
mesh_terms: D006801:Humans; D008310:Malocclusion / Q000628:therapy; D009967:Orthodontic Appliances / Q000009:adverse effects*; D016910:Orthodontic Brackets / Q000009:adverse effects; D012391:Root Resorption / Q000209:etiology*
keywords: Orthodontic aligner; Root resorption