title: Relationship between maxillary and mandibular base lengths and dental crowding in patients with complete Class II malocclusions.
abstract: OBJECTIVE
  To verify the relationship between maxillary and mandibular effective lengths and dental crowding in patients with Class II malocclusions.
  
  
  METHODS
  The sample comprised 80 orthodontic patients with complete Class II malocclusions in the permanent dentition (47 male, 33 female) who were divided into two groups according to the amount of mandibular tooth-arch size discrepancy. The maxillary and mandibular effective lengths (Co-A and Co-Gn) and tooth-arch size discrepancies were measured on the initial cephalograms and dental casts, respectively. Intergroup comparisons of apical base lengths were performed with independent t-tests. Correlation between base length and dental crowding was examined by means of Pearson's correlation coefficient (P < .05).
  
  
  RESULTS
  Patients with Class II malocclusion and moderate to severe crowding had significantly smaller maxillary and mandibular effective lengths than subjects with the same malocclusion and slight mandibular crowding. A weak inverse correlation was also found between maxillary and mandibular effective lengths and the severity of dental crowding.
  
  
  CONCLUSIONS
  Decreased maxillary and mandibular effective lengths constitute an important factor associated with dental crowding in patients with complete Class II malocclusion.
authors.affiliation: Department of Orthodontics, University of São Paulo, Bauru, Brazil. jansong@travelnet.com.br
authors.forename: Guilherme
authors.initials: G
authors.lastname: Janson
authors.forename: Oscar Edwin Francisco Murillo
authors.initials: OE
authors.lastname: Goizueta
authors.forename: Daniela G
authors.initials: DG
authors.lastname: Garib
authors.forename: Marcos
authors.initials: M
authors.lastname: Janson
mesh_terms: D000293:Adolescent; D017677:Age Distribution; D002508:Cephalometry; D002648:Child; D003724:Dental Arch / Q000473:pathology; D005260:Female; D006801:Humans; D007574:Jaw Relation Record; D008297:Male; D008310:Malocclusion; D008312:Malocclusion, Angle Class II / Q000473:pathology*; D008334:Mandible / Q000033:anatomy & histology*; D008437:Maxilla / Q000033:anatomy & histology*; D009811:Odontometry; D012189:Retrospective Studies; D017678:Sex Distribution; D018709:Statistics, Nonparametric; D019228:Tooth Crown / Q000033:anatomy & histology