title: [Anterior open bite: a formula for the differential diagnosis].
abstract: BACKGROUND
  The differentiation between dental and skeletal anterior open bite, both with distinct etiologies and characteristics, is necessary to establish adequate orthodontic and speech-language treatment procedures.
  
  
  OBJECTIVE
  To establish a formula for the differential diagnosis of dental anterior open bite and skeletal anterior open bite based on a cephalometric analysis of the angles that measure the mandibular plane inclination (NS.GoGn), the vertical and anteroposterior mandibular growth (NSGn), and the Facial Axis angle.
  
  
  METHODS
  78 lateral radiographies, of individuals with ages varying from 6 to 13 years, were analyzed and divided into two groups: dental anterior open bite and skeletal anterior open bite.
  
  
  RESULTS
  There was a significant difference between the groups regarding the measurements of the angles: for the group with skeletal anterior open bite the NS.GoGn and the NSGn angles were bigger and the Facial Axis angle was smaller when compared to the group with dental anterior open bite. The adjustment to the linear function resulted in a formula that determines the type of anterior open bite with only 3.5% of error.
  
  
  CONCLUSIONS
  It was possible to establish a high precision formula for the differential diagnosis between dental and skeletal open bite, based on the angle measurements of NS.GoGn NSGn and Facial Axes. The presented formula for the differential diagnosis has research and clinical applicability.
authors.affiliation: Motricidade Oral pela Universidade de Ribeirão Preto (Unaerp). heloalimere@bol.com.br
authors.forename: Heloísa Canesin
authors.initials: HC
authors.lastname: Alimere
authors.forename: Adílson
authors.initials: A
authors.lastname: Thomazinho
authors.forename: Cláudia Maria
authors.initials: CM
authors.lastname: de Felício
mesh_terms: D017677:Age Distribution; D000465:Algorithms; D002508:Cephalometry; D002648:Child; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008297:Male; D024343:Open Bite / Q000175:diagnosis*