title: [Preliminary clinical study on intrusion of overerupted molars with a removable appliance].
abstract: OBJECTIVE
  To evaluate the clinical effect of molar intrusion with a removable appliance and determine its clinical value.
  
  
  METHODS
  Seven patients were selected in the study.The clinical effect of intrusion was evaluated,the periodontal attachments and root resorption post-treatment were accessed by models,clinical examination, periapical radiograph analysis via CygnusRay2TM digital X-ray system pre and post-treatment.The data was analyzed using SAS6.12 software package.
  
  
  RESULTS
  All the overerupted molars had been intruded successfully within an average time of 3.7 months.Pre and post-treatment model analysis demonstrated the maximum intrusion amount was 3.05mm,minimum 1.03mm and mean 0.58mm per month.Analysis of pre and post-treatment periapical radiographs and periodontal probing depth showed no significant difference in probing depth,distance from cemento-enamel junction to alveolar bone crest,mesial and distal tooth length between pre- and post- treatment (P>0.05).
  
  
  CONCLUSIONS
  Molar intrusion with the removable appliance has a significant effect without apparent destruction of the periodontal tissue and root resorption.
authors.affiliation: Department of Orthodontics, College of Stomatology, Ninth People's Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200011, China. sherrya@citiz.net
authors.forename: Yi-ming
authors.initials: YM
authors.lastname: Yang
authors.forename: Si-en
authors.initials: SE
authors.lastname: Weng
authors.forename: Lin-ling
authors.initials: LL
authors.lastname: Chen
mesh_terms: D000539:Alveolar Process; D006801:Humans; D008963:Molar / Q000254:growth & development*; D009967:Orthodontic Appliances; D012391:Root Resorption; D014087:Tooth Movement Techniques