title: Upper midline deviation: modified Hyrax expander.
abstract: BACKGROUND
  The Hyrax rapid palatal expander is useful for patients in mixed dentition with premature exfoliation of some deciduous teeth and maxillary hypoplasia. This appliance, which is provided of a vestibular arm for correcting maxillary asymmetric transverse discrepancies, represents an interceptive treatment able to reduce the duration of the orthodontic therapy with fixed appliances.
  
  
  METHODS
  In this case report the modified version of the Hyrax rapid palatal expander is described. The activation method, the therapeutic benefits as well as the clinical advantages are described.
authors.affiliation: Department of Orthodontics, IRCCS Cà Granda, Ospedale Maggiore Policlinico, University of Milan, Milano, Italy.
authors.forename: G
authors.initials: G
authors.lastname: Farronato
authors.affiliation: Department of Orthodontics, IRCCS Cà Granda, Ospedale Maggiore Policlinico, University of Milan, Milano, Italy.
authors.forename: L
authors.initials: L
authors.lastname: Giannini
authors.affiliation: Department of Orthodontics, IRCCS Cà Granda, Ospedale Maggiore Policlinico, University of Milan, Milano, Italy.
authors.forename: G
authors.initials: G
authors.lastname: Galbiati
authors.affiliation: Department of Orthodontics, IRCCS Cà Granda, Ospedale Maggiore Policlinico, University of Milan, Milano, Italy.
authors.forename: C
authors.initials: C
authors.lastname: Maspero
mesh_terms: D002648:Child; D003818:Dentition, Mixed; D006801:Humans; D008297:Male; D016382:Orthodontic Appliance Design; D009967:Orthodontic Appliances; D010155:Palatal Expansion Technique / Q000295:instrumentation*