title: Validity of palatal superimposition of 3-dimensional digital models in cases treated with rapid maxillary expansion and maxillary protraction headgear.
abstract: OBJECTIVE
  The purpose of this study was to evaluate the validity of the 3-dimensional (3D) superimposition method of digital models in patients who received treatment with rapid maxillary expansion (RME) and maxillary protraction headgear.
  
  
  METHODS
  The material consisted of pre- and post-treatment maxillary dental casts and lateral cephalograms of 30 patients, who underwent RME and maxillary protraction headgear treatment. Digital models were superimposed using the palate as a reference area. The movement of the maxillary central incisor and the first molar was measured on superimposed cephalograms and 3D digital models. To determine whether any difference existed between the 2 measuring techniques, intra-class correlation (ICC) and Bland-Altman plots were analyzed.
  
  
  RESULTS
  The measurements on the 3D digital models and cephalograms showed a very high correlation in the antero-posterior direction (ICC, 0.956 for central incisor and 0.941 for first molar) and a moderate correlation in the vertical direction (ICC, 0.748 for central incisor and 0.717 for first molar).
  
  
  CONCLUSIONS
  The 3D model superimposition method using the palate as a reference area is as clinically reliable for assessing antero-posterior tooth movement as cephalometric superimposition, even in cases treated with orthopedic appliances, such as RME and maxillary protraction headgear.
authors.affiliation: Department of Orthodontics, College of Dentistry, Gangneung-Wonju National University, Gangneung, Korea.
authors.forename: Jin-Il
authors.initials: JI
authors.lastname: Choi
authors.forename: Bong-Kuen
authors.initials: BK
authors.lastname: Cha
authors.forename: Paul-Georg
authors.initials: PG
authors.lastname: Jost-Brinkmann
authors.forename: Dong-Soon
authors.initials: DS
authors.lastname: Choi
authors.forename: In-San
authors.initials: IS
authors.lastname: Jang