title: Prevalence, association, and sexual dimorphism of Carabelli's molar and shovel incisor traits amongst Jordanian population.
abstract: BACKGROUND
  The correlation between dental morphological traits can be used as an indicator to show major ethnic differences. Therefore, this study investigated the prevalence of Carabelli's molar and shovel incisor traits and tested their association and sexual dimorphism in Jordanian population.
  
  
  METHODS
  Three hundred subjects of school children at their 10th grade and of 15.5-year as an average age were involved. Alginate impressions for the maxillary arch were taken, poured, and casts were then trimmed. The selected accurate casts were of 132 male- and 155 female-students. The examined morphologic traits were Carabelli's trait on the maxillary first and second molars and shovel-shaped incisors. The relationship between different traits was investigated by Nonparametric Correlation analysis and Independent Sample t test was used to test sexual dimorphism in trait expression.
  
  
  RESULTS
  The prevalence of Carabelli's trait in maxillary first molar and shovel trait in maxillary central incisor was relatively high (65.0 % and 53.0 %, respectively). The prevalence of Carabelli's trait on maxillary second molars was 3.8 %. Nonparametric Correlations revealed a strongest positive correlation between Carabelli's trait on maxillary first molar and shovel trait in males (P = 0.005). Significant sexual dimorphism was only found in the prevalence of Carabelli's trait on maxillary first molar (P = 0.013) and shovel trait (P = 0.038).
  
  
  CONCLUSIONS
  The Jordanian Population had comparatively high prevalence of Carabelli's molar and shovel incisor traits. There was a positive association between Carabelli's trait on maxillary first molar and shovel trait in males. Sexual dimorphism was evident in Carabelli's trait on maxillary first molar and shovel trait.
authors.affiliation: Department of Conservative Dentistry and Prosthodontics, Faculty of Dentistry, University of Jordan, Amman, Jordan.
authors.forename: A
authors.initials: A
authors.lastname: Khraisat
authors.forename: Sahar T
authors.initials: ST
authors.lastname: Taha
authors.forename: R E
authors.initials: RE
authors.lastname: Jung
authors.forename: S
authors.initials: S
authors.lastname: Hattar
authors.forename: L
authors.initials: L
authors.lastname: Smadi
authors.forename: I K
authors.initials: IK
authors.lastname: Al-Omari
authors.forename: M
authors.initials: M
authors.lastname: Jarbawi
mesh_terms: D000293:Adolescent; D018912:Arabs; D005260:Female; D006801:Humans; D007180:Incisor / Q000033:anatomy & histology*; D007597:Jordan; D008297:Male; D008963:Molar / Q000033:anatomy & histology*; D015995:Prevalence; D012727:Sex Characteristics; D018709:Statistics, Nonparametric; D019228:Tooth Crown / Q000033:anatomy & histology*