摘要：The dental arches of the siblings apparently resemble one another in their form and measurement values. How about the dimension of tooth crown? This question stimulated the present authors to look into their relation. The materials used in this study are the plaster casts of upper and lower jaws obtained from the inhabitants in Kamiina District, Nagano Prefecture. On these plaster casts mesiodistal and buccolingual crown diameters were measured, and rectangle (mesiodistal diameter×buccolingual diameter) was calculated.
