title: Evaluation of mandibular anterior alveolus in different skeletal patterns.
abstract: BACKGROUND
  The boundaries for orthodontic tooth movement are set by the bony support of the dentition. This study compares the mandibular anterior alveolar housing in individuals with low, average, and high mandibular plane angles before orthodontic treatment and measures alveolar bone loss and root resorption after orthodontic treatment.
  
  
  METHODS
  Pretreatment cone-beam computed tomography (CBCT) images of 75 non-growing individuals, 25 in three groups: low-angle (sella-nasion to mandibular plane ≤28°), average-angle (30°-37°), and high-angle (≥39°), were analyzed. Buccolingual bone thickness was measured at the root apex, mid-root, and alveolar crest of the mandibular right central incisor. Pre- and posttreatment CBCT images of 11 low-angle, 20 average-angle, and 27 high-angle patients were compared to determine changes in the alveolus and mandibular incisor root after orthodontic treatment.
  
  
  RESULTS
  The pretreatment anterior alveolar bone widths were significantly different, wider in low-angle than in average- and high-angle individuals (p value = 0.000). High-angle individuals also had greater posttreatment external root resorption, even though the bony housing changed minimally.
  
  
  CONCLUSIONS
  Negative sequelae of orthodontic treatment are more frequently found in individuals with high mandibular plane angles and could be linked to their thin pre-existing alveolar housing.
authors.affiliation: Division of Orthodontics, School of Dentistry, University of California, San Francisco, USA.
authors.forename: Nga
authors.initials: N
authors.lastname: Hoang
authors.affiliation: Division of Orthodontics, School of Dentistry, University of California, San Francisco, USA.
authors.forename: Gerald
authors.initials: G
authors.lastname: Nelson
authors.affiliation: Division of Orthodontics, School of Dentistry, University of California, San Francisco, USA.|DDI Imaging Center, Sacramento, CA, USA.
authors.forename: David
authors.initials: D
authors.lastname: Hatcher
authors.affiliation: Division of Craniofacial Anomalies, School of Dentistry, University of California, San Francisco, USA. Sneha.Oberoi@ucsf.edu.|Division of Orthodontics, School of Dentistry, University of California, 707 Parnassus Ave, D-3000, San Francisco, CA, 94143, USA. Sneha.Oberoi@ucsf.edu.
authors.forename: Snehlata
authors.initials: S
authors.lastname: Oberoi
mesh_terms: D016301:Alveolar Bone Loss / Q000000981:diagnostic imaging*; D000539:Alveolar Process / Q000033:anatomy & histology* / Q000000981:diagnostic imaging*; D059925:Anatomic Landmarks / Q000000981:diagnostic imaging; D002508:Cephalometry; D054893:Cone-Beam Computed Tomography / Q000379:methods; D003817:Dentition; D005260:Female; D006801:Humans; D007180:Incisor / Q000033:anatomy & histology* / Q000000981:diagnostic imaging*; D008297:Male; D008334:Mandible / Q000033:anatomy & histology* / Q000000981:diagnostic imaging*; D015203:Reproducibility of Results; D012391:Root Resorption / Q000000981:diagnostic imaging; D019227:Tooth Apex / Q000033:anatomy & histology / Q000000981:diagnostic imaging; D014087:Tooth Movement Techniques / Q000009:adverse effects* / Q000379:methods; D014092:Tooth Root / Q000000981:diagnostic imaging; D020390:Tooth Socket / Q000033:anatomy & histology