title: Hyoid bone position and vertical skeletal pattern--open bite/deep bite.
abstract: The Hyoid Bone (HB) is a singular bone with no articulation, but is associated with some vital functions. The purpose of this study was to test the null hypotheses that there is no change in HB position in individuals with vertical jaw dysplasia.
  
  
  METHODS
  Eleven factors were used to determine the position of the HB. In this paper the ANOVA (two way analysis of variance) method was used to analyze the variability of the mean of each HB position according the factors facial type and gender. Comparisons with these procedures define which measurements were associated with facial type, gender; and the interactive associations between them.
  
  
  RESULTS
  The HB is related with vertical facial skeletal pattern being farther from mandible and a line joining it to the third cervical vertebra in deep bite, and from posterior nasal spine and sella turcica in open bite. There is sexual dimorphism in HB position. Men have a significant lower distance to the mandible and to the vertical pterigoidea; and higher values to the third cervical vertebra, to a line joining this vertebra to mandible, to the posterior nasal spine and to the sella turcica. Also, there is an association between HB position related group and gender.
  
  
  CONCLUSIONS
  In this research there is a relation between the position of HB and vertical skeletal pattern. The position of the HB is more related with deep bite. There is a possibility of including the HB in the differential diagnosis of this dysplasia.
authors.affiliation: Department of Orthodontics and Oral Facial Genetics, Faculty of Dentistry, Porto University, Rua Dr. Manuel Pereira da Silva, 4200-393 Porto, Portugal, Tel: +351917303631; Fax: +3515089021; e-mail: vandaurzal@gmail.com.
authors.forename: V
authors.initials: V
authors.lastname: Urzal
authors.forename: A C
authors.initials: AC
authors.lastname: Braga
authors.forename: A P
authors.initials: AP
authors.lastname: Ferreira