The Symmetrical Nature of Bilateral Asymmetry (δ) of Deciduous and Permanent Teeth

Although there have been numerous studies of crown-size asymmetry and its implications. effectively beginning with BALLARD (Anglo Ortho 14: 67-70, 1944) it is not known whether left-right crown-size asymmetry (8) is symmetrically or asymmetrically distributed and therefore whether means, standard deviations and such measures as S2 (SUAREZ, Am J Phys Anthrop 41:411-416, 1974) are appropriate for evolutionary or developmental comparisons. Accordingly we calculated individual buccolingual asymmetry values (8) for 24 pairs of teeth (14 permanent and 10 deciduous) from 201 subjects, using optical scanner measurements from serial casts of each subject (VAN DER LINDEN ET AL, J Dent Res 51:1100, 1972). Then, percentiles for left-right asymmetry were computed as well as the mean, the standard deviation, and the third moment about the mean (V3). As shown in the table, left-right asymmetry values (8) for both deciduous and permanent teeth are in general sufficiently symmetrical for