1 Orthodontic Department, School of Dentistry, Islamic Azad University, Shiraz, IR Iran

2 Orthodontic Department, Tehran University of Medical Sciences, Tehran, IR Iran


Background: It has been proved that, there's craniofacial asymmetry but much of this skeletal asymmetries are clinically ignorable. This asymmetry may exist in teeth size arranged in right and left sides of human mouth too. Orthodontists should pay attention to bilateral tooth asymmetry in treatment planning stage.
Objectives: This study was conducted to demonstrate whether the difference between size of left and right side teeth is actual.
Materials and Methods: A total of 200 plaster dental molds were used which were collected from a private practice in Tehran. A caliper with accuracy of 0.01 mm was used for measuring teeth and most teeth were measured twice and the average value was considered as the teeth size. In all cases, the Vernier calipers jaws were moved along the teeth longitudinal axis and the biggest width was measured in the contact point area.
Results: In average 83.16% of left and right teeth in upper jaw and 83.66% of left and right teeth in the lower jaw were not symmetrical and teeth in the upper and lower jaws were completely similar 16.84% and 16.34%, respectively.
Conclusions: The result of the study showed that nearly 83% of teeth in maxilla and mandible are asymmetric in mesiodistal width. Mandibular second molar and canine showed the highest and lowest bilateral asymmetry respectively.