The autoradiographic pattern of the in vitro uptake of proline by the coronal areas of intact and carious human teeth

Abstract

Whole crowns of human teeth, both immediately after extraction and after preservation in liquid nitrogen, were incubated for 6 h in the presence of [ 14C]- or [ 3H]-proline. Autoradiographs were prepared from sections of intact teeth and teeth with carious lesions of varying depths and location. The number of silver grains per cm 2 in the predentine, odonto-blast layer and pulp were counted in selected fields magnified × 430 representing the deepest parts of the carious lesions. No differences in the labelling pattern were observed between the intact teeth incubated freshly after extraction and those preserved in liquid nitrogen. The densest labelling of intact teeth was seen in the predentine and odontoblast layer. The alterations under initial dentine caries appeared as increased labelling of the predentine and decreased labelling of the odontoblast layer; no alterations were observed in the underlying pulp. In advanced lesions, the predentine labelling decreased and that in the odontoblast layer and pulp increased. In the initial stages, caries seems to activate collagen synthesis in a relatively restricted area of the underlying structures, but in more advanced stages, caries seems to increase the odontoblastic cellular polypeptide chain formation but prevent further maturation of the collagen.