A computerized analysis of dental arch morphology in early permanent dentition.

To determine the positions of teeth and the size and shape of the dental arches, 53 dental casts of children (29 boys and 24 girls) with their early permanent dentition and normal occlusions were examined. The coordinates of cusp tips and line angles of anterior teeth and cusp tips, contact points, and fossa of posterior teeth were digitized. Computer-generated curves were created for both arches using a polynomial model. There were 2 cusp-to-fossa relations and 4 cusp-to-marginal ridge relations for posterior segment intercuspation. Mean values of posterior arch lengths were statistically larger in boys than in girls. Mean curves of boys' dental arch forms were larger than those of girls and the ranges between the largest and smallest curves for both arches in boys were larger than those in girls. The boys' and girls' smallest curves for both arches were almost the same size.