This study compares the mesiodistal, buccolingual tooth sizes and their respective crown proportions in the moderate, mild, and noncrowded dental archs. The mesiodistal and buccolingual tooth sizes of all permanent teeth except the second and third molars were measured from 100 dental casts and their crown proportion was calculated. Tooth size measurements were made with a sliding caliper. Each dental arch was classified as presenting moderate dental arch, mild dental arch and noncrowded dental arch. The comparisons among the three groups for the tooth sizes and crown proportions were performed. The results showed that mesiodistal tooth sizes and crown proportions from almost individual teeth are significantly different between moderate, mild, and noncrowded arches, but no significant difference was observed among crowding groups for the buccolingual tooth sizes. The comparisons indicated differences for mesiodistal tooth size of all upper teeth (except second premolars) and for lower central incisors, lateral incisors and first premolars. Differences were also detected for crown proportions of the upper
central incisors, lateral incisors, canines, first premolar, as well as for the lower lateral incisors,. canines and first premolars.