title: [Investigation of the possible factors related to root resorption during orthodontic treatment in adolescents].
abstract: OBJECTIVE
  The purpose of this study was to investigate the factors relating to root resorption after orthodontic treatment in teenage patients.
  
  
  METHODS
  seventy eight teenage patients treated with fixed orthodontic appliances were selected for this study. Root resorption scores of the upper incisors were recorded qualitatively according to their apical root morphology in the panoramic radiographs before and after treatment. All subjects were grouped according to age, gender, tooth location, occlusion stage, extraction or nonextraction approach and treatment duration. Nonparametric tests was used for statistical analysis with SPSS12.0 software package.
  
  
  RESULTS
  All patients presented root resorption of different degrees. The results showed that there was significant difference before and after occlusion establishment of the second molar (P<0.01), but no difference between different age groups; Root resorption in extraction group was more severe than in non-extraction group (P<0.01); Root resorption in extraction group was more severe in patients with longer treatment duration (P<0.05). There was no significant difference between different genders and different teeth locations.
  
  
  CONCLUSIONS
  The results suggest that orthodontic treatment before occlusion establishment of the second molar, nonextraction approach and shorter treatment duration lead to less root resorption.
authors: Department of Orthodontics, School of Stomatology, Fujian Medical University, Fuzhou 350002, Fujian Province, China. dentistlinyan@yahoo.com.cn
authors: Yan
authors: Y
authors: Lin
authors: Ping-Ping
authors: PP
authors: Zhong
authors: Duan-Qiang
authors: DQ
authors: Zhang
mesh_terms: D000293:Adolescent; D006801:Humans; D007180:Incisor / Q000000981:diagnostic imaging; D008963:Molar; D009967:Orthodontic Appliances / Q000009:adverse effects*; D009971:Orthodontics, Corrective / Q000009:adverse effects*; D011862:Radiography, Panoramic; D012391:Root Resorption / Q000209:etiology*; D014081:Tooth Extraction