title: Alveolar bone level changes in maxillary expansion treatments assessed through CBCT.
abstract: OBJECTIVE
  Determine changes in alveolar bone levels during expansion treatments as assessed through cone-beam computer tomography (CBCT).
  
  
  METHODS
  Sixty-one patients from Edmonton, Canada, with maxillary transverse deficiencies were split into three groups. One group was treated with a bone-anchored expander, another group was treated with a tooth-borne maxillary expander (Hyrax) and one group was untreated. CBCTs were obtained from each patient at two time points (initialT1and at removal of appliance after 6 months T2). CBCTs were analyzed using AVIZO software and landmarks were placed on different dental and skeletal structures. Intra-examiner reliability for landmarks was done by randomly selecting 10 images and measuring each landmark 3 times, 1 week apart. Descriptive statistics, intraclass correlation coefficients (ICC) and ANOVA analysis were used to determine if there were changes to the alveolar bone levels and if these changes were statistically significant within each group.
  
  
  RESULTS
  Landmarks reliability showed an ICC of at least 0.99 with a 95% confidence interval and a mean measurement error of at least 0.2067mm. Descriptive statistics show that changes in alveolar bone levels were less than 1mm for all three groups and therefore clinically insignificant. Changes between groups were not statistically different (P<0.05) from one another with the exception of 8 distances. However, since the distances were small, they were not considered clinically significant.
  
  
  CONCLUSIONS
  Alveolar bone level changes were similar in maxillary expansion treatments and in the control group. The effects of maxillary expansion treatments on alveolar bone levels are not clinically significant.
authors.affiliation: ECHA 5-524, Department of Dentistry, University of Alberta, T5G 2N8 Edmonton, AB, Canada.
authors.forename: Vi
authors.initials: V
authors.lastname: Pham
authors.affiliation: ECHA 5-524, Department of Dentistry, University of Alberta, T5G 2N8 Edmonton, AB, Canada. Electronic address: manuel@ualberta.ca.
authors.forename: Manuel O
authors.initials: MO
authors.lastname: Lagravère
mesh_terms: D000539:Alveolar Process / Q000000981:diagnostic imaging*; D054893:Cone-Beam Computed Tomography; D006801:Humans; D008310:Malocclusion / Q000000981:diagnostic imaging / Q000473:pathology / Q000628:therapy; D052280:Orthodontic Anchorage Procedures / Q000379:methods; D010155:Palatal Expansion Technique
keywords: Cone-beam computer tomography; Orthodontics; Rapid maxillary expansion