[Resemblance of nonmetrical trait of tooth crown among siblings and between parents and children].
An elaborate observation and comparative study was made on the degree of resemblance among siblings, and parents and their children employing, as a means of investigation, the tooth crowns of the plaster casts of upper and lower jaws obtained from the inhabitants of Kamiina District, Nagano Prefecture. The comparisons were made between the right and left sides of an individual and also free pairs of individuals taken at random. To reach a decision on the degree of resemblance, the following factors were utilized: the degree of resemblance, interfamily correlation, and the percentage of heredity. Genealogies were also taken into consideration in some cases of tooth crowns. The main point of the results of this study is that the degree of resemblance among siblings, parents and their children differs according to the kind of tooth crown. 1. The degree of resemblance was most remarkable in the case of the following four morphological peculiarities the labial relief of incisors (I1, I2), shovel shaped incisors (I1), basal tubercle (C'), and mesial interstitial tubercle (P1). 2. Not so much as the four morphological peculiarities mentioned above but still considerable was the degree of resemblance on the singular tubercle of the Carabelli tubercle (M1), protostylid (M1), sixth cusp (M1), etc., and the tetracuspid type of the second lower molars, basal tubercle (I1). These were followed by the interstitial tubercle (P2) and the tricuspid type of the second upper molar with only a slight difference. 3. Resemblance of the basal tubercle (I2), Carabelli tubercle (M2), protostylid (M2), sixth cusp (M2), reduction of the upper lateral incisor, or Metacone reduction (M2) was rarely observed. 4. Resemblance between the permanent teeth of a mother and the deciduous teeth of her child was also rare, except the shovel shaped ones. 5. Generally, the degree of resemblance decreased in the following order: between the right and left sides, between siblings, between parents and their children, and finally, among unrelated pairs. Most outstanding was the resemblance between the right and left sides.
Ohba
H
H
D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D002675:Child, Preschool; D006801:Humans; D007180:Incisor / Q000033:anatomy & histology; D007223:Infant; D007231:Infant, Newborn; D007564:Japan; D008875:Middle Aged; D009811:Odontometry; D014070:Tooth / Q000033:anatomy & histology*; D014094:Tooth, Deciduous / Q000033:anatomy & histology*