title: [Evaluation of the orthodontic treatment outcome in patients with impacted maxillary central incisor in the mixed dentition].
abstract: OBJECTIVE
  To evaluate the orthodontic treatment outcome in patients with impacted maxillary central incisor in the mixed dentition.
  
  
  METHODS
  Nine patients, aged 8 to 11 years, with impacted maxillary central incisor were treated orthodontically. The cone-beam CT(CBCT) was taken before treatment, after treatment and one year out of retention to evaluate the root length, root canal wall thickness, width of the apical foramen, and degree of root bending, alveolar bone height and thickness. The crown-to-root ratio was calculated. The periodontal and endodontic conditions were evaluated. The parameters of the treated incisors and contralateral ones served as controls were compared.
  
  
  RESULTS
  Nine impacted teeth were treated successfully. Throughout the treatment, the root of impacted central incisor continued to develop and the alveolar bones also continued to develop and remodel. The condition of the alveolar bone of vertically impacted teeth was better than that of horizontally impacted ones. No periodontal pocket or pulp necrosis was found after treatment. Seven patients were examined one year after treatment. No significant difference was found in root length, palatal alveolar bone level and palatal alveolar bone thickness. The control group root length was (13.07±2.15) mm, the treatment group root length was (12.06±2.00) mm. No further alveolar bone loss, gingival recession and pulp necrosis were found. The control group labial and palatal alveolar bone levels were (0.90±0.62), (0.45±0.52) mm, labial and palatal alveolar bone thickness were (0.85±0.14), (1.21±0.41) mm. The treatment group labial and palatal alveolar bone levels were (2.18±1.59) mm, (0.57±0.71) mm, labial and palatal alveolar bone thickness were (0.48±0.29), (1.43±0.31) mm.
  
  
  CONCLUSIONS
  Orthodontic therapy for impacted maxillary central incisor in the mixed dentition could promote root development and alveolar bone remodeling. Good periodontal and endodontic conditions were achieved.
authors.affiliation: The Second Outpatient Dental Clinic, Peking University School and Hospital of Stomatology, Beijing 100010, China.
authors.forename: Can
authors.initials: C
authors.lastname: Cheng
authors.affiliation: Department of Orthodontics, Peking University School and Hospital of Stomatology, Beijing 100081, China.
authors.forename: Xiaotong
authors.initials: X
authors.lastname: Li
authors.affiliation: Department of Pediatric Dentistry, Peking University School and Hospital of Stomatology, Beijing 100081, China.
authors.forename: He
authors.initials: H
authors.lastname: Liu
mesh_terms: D016301:Alveolar Bone Loss / Q000000981:diagnostic imaging; D002648:Child; D054893:Cone-Beam Computed Tomography; D003818:Dentition, Mixed; D005889:Gingival Recession / Q000000981:diagnostic imaging; D006801:Humans; D007180:Incisor / Q000000981:diagnostic imaging; D008437:Maxilla; D009970:Orthodontics / Q000379:methods*; D019227:Tooth Apex / Q000000981:diagnostic imaging; D019228:Tooth Crown / Q000000981:diagnostic imaging; D014092:Tooth Root / Q000000981:diagnostic imaging; D014095:Tooth, Impacted / Q000000981:diagnostic imaging / Q000628:therapy*; D016896:Treatment Outcome