The Relative Sexual Dimorphism of Human Incisor Crown and Root Dimensions

Abstract

Teeth are unusual structures in that theirdimensions are sexually dimorphic even though theyform early in life, several years before steroid-mediatedadolescence. These size differences make teeth attractiveas indicators of a specimen’s sex. Alternatively, themagnitude of sexual dimorphism in humans is low, sothere is considerable overlap in sizes between the twosexes. Prior studies suggest that tooth root dimensionsare more dimorphic than crown dimensions, so rootswould be more useful for sex determination. Toexplore this, we measured the four incisor tooth typesfrom standardized periapical radiographs in a sample(n = 148) of living American white adolescents. Rootlengths are somewhat more dimorphic than crownsizes in this sample (ca. 6% vs. 2%), and this translatesinto somewhat higher discriminatory power. Thehindrance, however, is that all crown and root sizesare positively intercorrelated, so there is effectivelyjust one dentition-wide axis of “tooth size” variation.Statistically, at least for these incisor tooth types, thereis no added discriminatory power in the crown sizesonce root dimensions have been accounted for, thoughthe addition of data from other tooth types mightimprove discrimination somewhat.

Cite this work

No public copy is stored for this record, so only the metadata is cited.

Stored only when both papers are in the corpus — 16 citations exist upstream.

Papers that cite the same references — the relational fallback while embeddings are still backfilling.