title: The inclination of mandibular incisors revisited.
abstract: OBJECTIVE
  To reassess the inclination of lower incisors and evaluate possible associations with gender, age, symphyseal parameters, and skeletal pattern.
  
  
  METHODS
  Twelve hundred and seventy-two (605 females, 667 males) cephalograms of untreated subjects of a craniofacial growth study (age: 8-16 years) were evaluated. Correlations between the angulation of the lower incisors and age, symphyseal distances (height, width, and depth), symphyseal ratios (height-width, height-depth), and skeletal angles (divergence of the jaws and gonial angle) were investigated for all ages separately and for both sexes independently.
  
  
  RESULTS
  The inclination of lower incisors increased over age (8 years: girls = 93.9° [95% CI, 92.3°-95.7°], boys = 93.3° [95% CI, 91.8°-94.9°]; 16 years: girls = 96.1° [95% CI, 94.1°-98.2°], boys = 97.1° [95% CI, 95.6°-98.6°]). Inclination of lower incisors correlated with the divergence of the jaws for all ages significantly or highly significantly, except for boys and girls 9 years of age and girls 11 and 12 years of age, for which only a tendency was observed. Similarly, a strong correlation to gonial angle could be observed. No correlation could be found between the inclination of lower incisors and any symphyseal parameters (absolute measurements and ratios), except for symphyseal depth.
  
  
  CONCLUSIONS
  Lower incisor inclination is linked to the subject's sex, age, and skeletal pattern. It is not associated with symphyseal dimensions, except symphyseal depth. Factors related to natural inclination of lower incisors should be respected when establishing a treatment plan.
authors.affiliation: a  Research Fellow, Department of Orthodontics and Pediatric Dentistry, Center for Dental Medicine, University of Zurich, Zurich, Switzerland.
authors.forename: Cécile
authors.initials: C
authors.lastname: Gütermann
authors.forename: Timo
authors.initials: T
authors.lastname: Peltomäki
authors.forename: Goran
authors.initials: G
authors.lastname: Markic
authors.forename: Michael
authors.initials: M
authors.lastname: Hänggi
authors.forename: Marc
authors.initials: M
authors.lastname: Schätzle
authors.forename: Luca
authors.initials: L
authors.lastname: Signorelli
authors.forename: Raphael
authors.initials: R
authors.lastname: Patcas
mesh_terms: D000293:Adolescent; D000367:Age Factors; D059925:Anatomic Landmarks / Q000033:anatomy & histology; D002508:Cephalometry / Q000379:methods*; D002648:Child; D002680:Chin / Q000033:anatomy & histology; D003724:Dental Arch / Q000033:anatomy & histology / Q000254:growth & development; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D007180:Incisor / Q000033:anatomy & histology*; D008297:Male; D008334:Mandible / Q000033:anatomy & histology* / Q000254:growth & development; D008437:Maxilla / Q000033:anatomy & histology; D012737:Sex Factors