title: Formants frequency and dispersion in relation to the length and projection of the upper and lower jaws.
abstract: OBJECTIVE
  Investigate the association between formants frequencies and length and sagittal projection of the maxilla and mandible.
  
  
  METHODS
  Cross-sectional study.
  
  
  METHODS
  A total of 47 consecutive patients were recruited. Craniofacial measures included; maxillary length (ANS-PNS), mandibular length (Co-Gn), relationship between maxilla and mandible in the sagittal plane (ANB), the sagittal projection of the maxilla (SNA), and mandible (SNB). Subjects were asked to phonate vowels /a/, /i/, /o/, and /u/. Measurements were made in real-time and formant frequencies across F1, F2, F3, and F4 were determined.
  
  
  RESULTS
  There was a significant negative association between the length of the maxilla and F4 for all the vowels, and a significant negative association between the length of the mandible and F4 for vowels /o/ and /u/. The length of maxilla and mandible also negatively associated with F3 for vowels /a/, /i/, /o/, and vowels /i/, /o/, and /u/ respectively. For the first two formants, the negative association was less pronounced.
  
  
  CONCLUSIONS
  There was a significant negative association between the formant frequencies F3, F4, and the length of the mandible and maxilla for vowels /a/, /i/, /o/, and /u/.
authors.affiliation: Division of Orthodontics and Dentofacial Orthopedics, Department of Otolaryngology-Head & Neck Surgery, American University of Beirut Medical Center, Beirut, Lebanon.
authors.forename: Anthony T
authors.initials: AT
authors.lastname: Macari
authors.affiliation: Division of Orthodontics and Dentofacial Orthopedics, Department of Otolaryngology-Head & Neck Surgery, American University of Beirut Medical Center, Beirut, Lebanon.
authors.forename: Ingrid A
authors.initials: IA
authors.lastname: Karam
authors.affiliation: Department of Otolaryngology-Head & Neck Surgery, American University of Beirut Medical Center, Beirut, Lebanon.
authors.forename: Dollen
authors.initials: D
authors.lastname: Tabri
authors.affiliation: Department of Otolaryngology-Head & Neck Surgery, American University of Beirut Medical Center, Beirut, Lebanon.
authors.forename: Doja
authors.initials: D
authors.lastname: Sarieddine
authors.affiliation: Department of Otolaryngology-Head & Neck Surgery, American University of Beirut Medical Center, Beirut, Lebanon. Electronic address: ah77@aub.edu.lb.
authors.forename: Abdul-Latif
authors.initials: AL
authors.lastname: Hamdan
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D008334:Mandible / Q000033:anatomy & histology* / Q000502:physiology; D008437:Maxilla / Q000033:anatomy & histology* / Q000502:physiology; D013061:Speech Acoustics; D014831:Voice; D055815:Young Adult
keywords: Formants frequencies; Mandible; Maxilla