Application of the cubic spline function in the description of dental arch form.

Cubic splines were fitted to the maxillary dental arches of 27 children with permanent dentitions, all having Class I molar, cuspid, and buccal segment relationships. A set ofdata points was chosen to represent arch form, and of these points, five were used as knots of the spline. Error of the fit of the curve was evaluated through the analysis of normals to the curve computed from those points not used as knots. Analysis demonstrates that the errors are minimal, and the spline function appears to adequately represent either symmetric or asymmetric dental arch forms.