Fatemeh Gorjizadeh - Orthodontic Department, Tehran University of Medical Sciences, Tehran, IR Iran
Maryam Javaheri Mahd - Orthodontic Department, Tehran University of Medical Sciences, Tehran, IR Iran
Abdo Rahim Maktabi - Orthodontic Department, Tehran University of Medical Sciences, Tehran, IR Iran

Background Prediction of the mesio-distal width of the unerupted premolars and canine is an important point to the practitioner. Objectives The main goal of this study was to find the relationship of the teeth size to be used when needed in treatments planning. Materials and Methods ۲۰۰ plaster casts including ۵۶۰۰ teeth were measured and studies. A caliper with accuracy of ۰.۱ 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 Tables of mesiodistal widths of the permanent teeth and some equations were prepared. The measurement difference varied from ۰ to ۰.۰۴ mm. the average value of difference was ۰.۰۱۶ mm with SD of ۰.۰۲ mm. All teeth in male are bigger than those in female and this different is most evident in canine teeth, especially the lower jaw canine teeth. Conclusions At the end of this study an equation was found which was used to measure the total value of mesiodistal width of canine and premolar teeth of upper and lower jaws in a simple and exact way.

Mesiodistal Widths, Tooth Size Discrepancy, Malocclusion, Bolton Analysis