ENAMEL THICKNESS IN 45,X FEMALES PERMANENT TEETH

  • 1 January 1981
    • journal article
    • research article
    • Vol. 33  (3) , 464-469
Abstract
Enamel thicknesses in 45,X human females'', their male and female relatives'', and population control males'' and females'' permanent tooth crowns were determined from radiographs. The enamel layer in both maxillary 1st incisors and canines of 45,X females is definitely thinner than that of control males or females. Enamel in control males'' and females'' teeth was about equal in size. The distance between mesial and distal dentino-enamel junctions or the thickness of dentin was similar in 45,X females'' and in control females'' teeth, but definitely smaller than in control males'' teeth. In the presence of the 2nd sex-chromosome in the chromosome complement, whether X or Y, there is evidently a definite and equal increase in the amount of enamel. In the presence of the Y chromosome in the chromosome complement, relative to the 2nd X chromosome, there is a definite increase in the thickness of the dentin. A direct growth-promoting effect of the sex chromosomes on tooth growth and a different effect of X and Y chromosomes was seen previously. The influence of the X- and Y-chromosome gene(s) on amelogenesis apparently is the same in quantitative terms but different in relation to the determination of the distance between dentino-enamel junctions; the Y chromosome is more effective than the X chromosome in that respect. This size-increasing effect of the Y-chromosome gene(s) might result from its profound effect on cell proliferations.