Expression of Carabelli trait in children from Southern India - A cross sectional study

BACKGROUND: The distribution of the Carabelli trait is highly variable in different regions and races of the world. OBJECTIVE: To determine the prevalence of Carabelli trait in a group of children from Nellore. MATERIALS AND METHODS: Children who attended the department between October 2011 to March 2012 were selected and examined for the expression of Carabelli trait in the maxillary primary second molar, permanent first and permanent second molars on the basis of the classification developed by Kraus and standards developed by Dahlberg. STATISTICAL METHODS: Descriptive statistics was performed and the relative frequency of expression in each category, according to Kraus's and Dahlberg's classification was calculated. Sexual dimorphism was statistically analyzed using Mann-Whitney U-test. RESULTS: A total of 89.8% of primary second molars, 63.7% of permanent first molars, and 8% of permanent second molars showed some form of expression of Carabelli trait in the target population. CONCLUSION: Though there was a high frequency of intermediate expressions of this trait, occurrence of a definite cusp of Carabelli on the primary maxillary second molar and permanent maxillary first molar was relatively infrequent. A high percentage of the permanent maxillary second molars showed complete absence of Carabelli trait and there was no sexual dimorphism. Bilateralism with varying degrees of asymmetry was noted and there was tendency for concordance between the two sides but not within individual sides.