Increased crown-size asymmetry in trisomy G.
نویسندگان
چکیده
Trisomy G (Down's syndrome or "mongolism") is associated with multiple dental abnormalities (J. OSTER, Mongolism, Copenhagen: Danish Science Press, 1953). Teeth are frequently missing, all morphologic classes are involved, and the remaining teeth are characterized by size reduction (M. M. COHEN and A. WINER, I Dent Res 44:197-208, 1965; and M. M. COHEN, S. M. GARN, and M. A. GECIAUSKAS, J Dent Res 49:460, 1970). One might therefore expect an increase in the magnitude of bilateral (leftright) crown-size asymmetry, especially for the more variable lateral tooth of each morphologic class. To test this hypothesis we calculated individual left-right crown size asymmetry values (d) for paired antimeres in 47 instances of trisomy G. Nineteen of these verified instances were in males and 28 were in females. For each tooth pair the RMS (root mean square) asymmetry value (ad) for the mesiodistal crown diameter was computed as previously described. (S. M. GARN, A. B. LEWIS, and R. KEREWSKY, Angle Ortho 36:55-62, 1966). The sexand tooth-specific values of RMS asymmetry in the subjects with trisomy G were then compared to the "normal" values, previously published. As shown in the table, crown-size asymmetry of the permanent teeth in subjects with Down's syndrome systematically exceeds RMS bilateral asymmetry of normal subjects. This is true for all 14 teeth considered, and in both sexes, with an observed ratio of 28:0 as against the 14:14 or chance hypothesis. Furthermore, the magnitude of RMS asymmetry in these 47 subjects
منابع مشابه
Relative magnitudes of crown size reduction and body size reduction in 47-trisomy G.
Since crown size reduction has been observed in 47-trisomy G (M. M. COHEN and R. A. WINER, J Dent Res 44:197-208, 1965; M. M. COHEN, S. M. GARN, and M. A. GECIAUSKAS, J Dent Res 49:460, 1970) with delayed tooth formation timing (S. M. GARN, C. W. STIMSON, and A. B. LEWIS, J Dent Res 49:640, 1970), it is useful to compare the magnitude of crown size reduction with the magnitude of body size redu...
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عنوان ژورنال:
- Journal of dental research
دوره 49 2 شماره
صفحات -
تاریخ انتشار 1970