title: Cephalometric and dental arch changes to Haas-type rapid maxillary expander anchored to deciduous vs permanent molars: a multicenter, randomized controlled trial.
abstract: OBJECTIVE
  To assess radiographic changes and dental arch changes with Haas-type rapid maxillary expansion (H-RME) anchored to deciduous versus permanent molars in children with unilateral posterior crossbite.
  
  
  METHODS
  In all, 70 patients with unilateral posterior crossbite were randomly allocated to group GrE (H-RME on second deciduous molars) or Gr6 (H-RME on first permanent molars) and compared between T0 (before treatment) and T1 (at the RME removal; i.e., 10 months after the end of the activation of the screw). At T0 and T1, cephalometric head films were digitally traced, dental casts were scanned, and rotations of the upper first molars, of the upper central, and of the upper lateral incisors on the models were measured.
  
  
  RESULTS
  Between T0 and T1, the cephalometric analysis showed a significant decrease of the angulation of the upper central incisors to the SN line and to the palatal plane in GrE together with a significant increase of the lower incisors to the mandibular plane (IMPA). The digital dental cast analysis showed that the central and lateral incisors mesiorotated significantly more in GrE than in Gr6. Patients in GrE also showed a statistically significant distorotation of the upper first permanent molars after RME.
  
  
  CONCLUSIONS
  GrE showed a significant and spontaneous retraction and alignment of the upper central and lateral incisors compared to Gr6. This is probably due to a more pronounced expansion in the anterior area and more accentuated pressure of the upper lip in GrE. IMPA increased significantly in GrE vs Gr6. GrE also showed a more significant distorotation of the upper first permanent molars compared to Gr6. This is probably due to the design of the H-RME in GrE, where the screw is more anteriorly positioned and the bands are absent on the upper first permanent molars which are, therefore, free to adapt to the best occlusal situation.
  
  
  BACKGROUND
  ClinicalTrials.gov Identifier NCT02798822.
authors.affiliation: Private Practice in Siena, Siena, Italy.
authors.forename: Carmen
authors.initials: C
authors.lastname: Cerruto
authors.affiliation: Division of Orthodontics, Department of Surgical and Diagnostic Sciences, University of Genoa, Genoa, Italy. alexugolini@yahoo.it.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Ugolini
authors.affiliation: Division of Orthodontics, Department of Medical Biotechnologies, University of Siena, Siena, Italy.
authors.forename: Luca
authors.initials: L
authors.lastname: Di Vece
authors.affiliation: Division of Orthodontics, Department of Medical Biotechnologies, University of Siena, Siena, Italy.
authors.forename: Tiziana
authors.initials: T
authors.lastname: Doldo
authors.affiliation: Division of Orthodontics, Department of Surgical and Morphological Sciences, University of Insubria, Varese, Italy.
authors.forename: Alberto
authors.initials: A
authors.lastname: Caprioglio
authors.affiliation: Division of Orthodontics, Department of Surgical and Diagnostic Sciences, University of Genoa, Genoa, Italy.
authors.forename: Armando
authors.initials: A
authors.lastname: Silvestrini-Biavati
mesh_terms: D002508:Cephalometry; D002648:Child; D003724:Dental Arch / Q000033:anatomy & histology* / Q000601:surgery; D019229:Dentition, Permanent; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional; D007180:Incisor; D008297:Male; D008310:Malocclusion / Q000000981:diagnostic imaging / Q000601:surgery / Q000628:therapy; D008963:Molar; D052280:Orthodontic Anchorage Procedures / Q000295:instrumentation*; D010155:Palatal Expansion Technique / Q000295:instrumentation*; D014094:Tooth, Deciduous
keywords: Cephalometric changes; Deciduous vs permanent molars; Rapid maxillary expansion; Three-dimensional