title: Computed tomography evaluation of mandibular incisor bony support in untreated patients.
abstract: BACKGROUND
  In this study, we aimed to verify, via computed volumetric tomography, a correlation between the morphology of the mandibular symphysis and the various facial types.
  
  
  METHODS
  From a sample of 148 digital volumetric tomographs, the subjects were classified as either short face (25 subjects), normal face (27 subjects), or long face (28 subjects) according to the average values of their Frankfort-mandibular plane angle. The 80 healthy subjects were between 12 and 40 years of age. Tomography was carried out using NewTom 3G volume scanner (QRsr1, Verona, Italy). The following parameters were measured on the sections corresponding to the 4 mandibular incisors: height, thickness, and area of the entire symphysis; height, thickness, and area of the cancellous bone of the symphysis; distance of the vestibular and lingual cortices from the apices of the 4 incisors; and possible inclination of each mandibular incisor, expressed in degrees. The F test or analysis of variance (ANOVA) and the Tukey HSD Test were subsequently used.
  
  
  RESULTS
  The total thickness of the symphysis was greater in the short-face subjects than in the long-face subjects. No statistically significant differences in the total and cancellous areas of the symphysis were found between the 3 facial types. In all 3 groups, the total and cancellous heights and areas were greater at the central incisors than at the lateral incisors.
  
  
  CONCLUSIONS
  There is a statistically significant relationship between facial type and the total thickness of the mandibular symphysis.
authors.affiliation: Postgraduate School of Orthodontics, University of Ferrara, Department of Orthodontics, University of Ferrara, Ferrara, Italy. antoniogracco@libero.it
authors.forename: Antonio
authors.initials: A
authors.lastname: Gracco
authors.forename: Lombardo
authors.initials: L
authors.lastname: Luca
authors.forename: Maria Cristina
authors.initials: MC
authors.lastname: Bongiorno
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Siciliani
mesh_terms: D000293:Adolescent; D000328:Adult; D000539:Alveolar Process / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D000704:Analysis of Variance; D002508:Cephalometry; D002648:Child; D054893:Cone-Beam Computed Tomography; D005145:Face / Q000033:anatomy & histology*; D006801:Humans; D007180:Incisor / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D008334:Mandible / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D012016:Reference Values; D055815:Young Adult