Expression of Carabelli’s trait in the Jordanian population

This study aimed at presenting and reviewing the prevalence, sexual dimorphism and bilateralism of Carabelli’s trait in the Jordanians.

The presence of different forms of Carabelli’s trait expression on first and second maxillary molars was examined in 2,172 and 564 Jordanians, respectively.

The prevalence of the positive forms of Carabelli’s trait in maxillary first molars was 38% and significantly lower than the previously reported frequency in Jordanians. However, the prevalence of the positive forms of the trait in maxillary second molars (8%) was similar to what has been previously reported. On the other hand, the prevalence of the negative expression form of the trait in first and second molars was 10% and 16%, respectively. In addition, sexual dimorphism was insignificant in the expression of the trait in first molars although weakly significant in second molars. Furthermore, the expression of Carabelli’s trait was significantly bilateral in the maxillary first molar although bilateralism in the second molar was only significant in females.

In the light of the published data among different Caucasoid groups, the present study provides more reliable data on the expression of Carabelli’s trait than the previously published data on Jordanians. Clinically, the expression of the different forms of Carabelli’s trait do not seem to present significant clinical problems in restorative dentistry in Jordan although the positive forms may present minor challenges in orthodontics.