title: Comparison of the changes of alveolar bone thickness in maxillary incisor area in extraction and non-extraction cases: computerized tomography evaluation.
abstract: OBJECTIVE
  To compare, through computed tomography, alveolar bone thickness changes at the maxillary incisors area during orthodontic treatment with and without tooth extraction.
  
  
  METHODS
  Twelve patients were evaluated. They were divided into 2 groups: G1--6 patients treated with extraction of right and left maxillary first premolars, with mean initial age of 15.83 years and mean treatment length of 2.53 years; G2--6 patients treated without extraction, with mean initial age of 18.26 years and mean treatment length of 2.39 years. Computed tomographies, lateral cephalograms and periapical radiographs were used at the beginning of the treatment (T1) and 18 months after the treatment had started (T2). Extraction space closure occurred in the extraction cases. Intragroup and intergroup comparisons were performed by dependent and independent t test, respectively.
  
  
  RESULTS
  In G1, the central incisor was retracted and uprighted, while in G2 this tooth showed vestibularization. Additionally, G1 presented a higher increase of labial alveolar bone thickness at the cervical third in comparison with G2. The incidence of root resorption did not present significant differences between groups.
  
  
  CONCLUSIONS
  There were no changes in alveolar bone thickness when extraction and nonextraction cases were compared, except for the labial alveolar bone thickness at the cervical third of maxillary incisors.
authors.forename: Paulo Roberto Barroso
authors.initials: PR
authors.lastname: Picanço
authors.forename: Fabricio Pinelli
authors.initials: FP
authors.lastname: Valarelli
authors.forename: Rodrigo Hermont
authors.initials: RH
authors.lastname: Cançado
authors.forename: Karina Maria Salvatore
authors.initials: KM
authors.lastname: de Freitas
authors.forename: Gracemia Vasconcelos
authors.initials: GV
authors.lastname: Picanço
mesh_terms: D000293:Adolescent; D016301:Alveolar Bone Loss / Q000209:etiology*; D000539:Alveolar Process / Q000000981:diagnostic imaging / Q000503:physiopathology*; D001641:Bicuspid / Q000601:surgery; D015519:Bone Density; D016009:Chi-Square Distribution; D002648:Child; D005260:Female; D006801:Humans; D007180:Incisor; D008297:Male; D008311:Malocclusion, Angle Class I / Q000628:therapy*; D008312:Malocclusion, Angle Class II / Q000628:therapy*; D008437:Maxilla / Q000000981:diagnostic imaging / Q000503:physiopathology*; D009971:Orthodontics, Corrective / Q000009:adverse effects / Q000379:methods*; D012391:Root Resorption / Q000209:etiology; D014057:Tomography, X-Ray Computed; D014081:Tooth Extraction / Q000009:adverse effects; D055815:Young Adult
keywords: Alveolar ridge; Tomography; Tooth extraction; Tooth movement