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Multivariate analyses of arch morphology (permanent denti­tion) reveal two principal components of variation: a size component with high positive correlations between measures and a shape component con­trasting arch widths and depths. Analyses of the size component show that males are significantly larger than females. Variation also exists between arches, with the maxilla being significantly larger than the mandible. Anal­yses of the shape component show that, independent of size, the maxilla is relatively longer and narrower than the mandible. Sexual dimorphism in dental arch shape is not significant. Chronological age differences between subjects do not explain variation in either size or shape.