Aim The purpose of the present research was to evaluate the variations in the shape of maxillary and mandibular dental arches in a population undergoing orthodontic treatment. Methodology Dental casts of 133 white subjects (61 males, 72 females; ages 10.6–26.6) were scanned and digitized in three dimensions. Landmarks were placed on the incisal margins and on the cusps of canines, premolars, and molars. Geometric morphometric methods were applied (Procrustessuperimposition and principal component analysis). Sexual dimorphism and allometry were evaluated with permutation tests and age–size and age–shape correlations were computed. Two block partial least squares analysis was used to assess covariation of shape.