Sexual dimorphism related to occlusal traits in Australian children

Abstract

Background: The aim of the present study was to assess sexual dimorphism related to occlusal variables recorded from dental casts of Australian twins and to compare trends across primary (T1), mixed (T2) and permanent (T3) dentitions in the same individuals. Methods: The sample comprised 22 males and 25 females selected at random from monozygotic pairs and 19 males and 19 females from dizygotic pairs. Overjet, overbite, midline deviation, midline diastema, primary and permanent molar relationship, and primary and permanent canine relationships were measured in millimetres using a digital calliper. Results: The mean values for overjet in males in the permanent dentition and for overbite in the mixed and permanent dentitions were significantly greater than those for females. The other occlusal traits showed no sexual dimorphism. Midline diastemata were most prevalent in the primary dentition while coincident midlines were most prevalent at all stages for both genders. In addition, a mesial step deciduous molar relationship was more prevalent on the right side and a flush terminal plane present on the left. Furthermore, a Class II permanent molar relationship was predominant in T1/T2, while a Class I relationship was most prevalent in the permanent dentition. Class II primary and permanent canine relationships were most common at all stages. Conclusions: Significant sexual dimorphism was found for overjet and overbite at several occlusal developmental stages but sexual dimorphism was not found for the other occlusal traits studied.