[Glycoproteins and proteoglycans in the predentin and dentin matrix in the rat: an ultrastructural study]

The ultrastructural distribution of the protein-polysaccharides was studied in the predentinal and dentinal matrices of the rat. Used for the indentification of the glycoproteins, the chromic-phosphotungstic acid mixture (Rambourt, 1967) weakly contrasted the predentine, underlined the mineralization front and impregnated the dentinal matrix. Alcian blue (Goldberg et al., 1977) as well as bismuth nitrate (Serafini-Fracassini and Smith, 1966), cationic stains for the proteoglycans, produced a strong contrast in the predentine, whereas in the dentine, which appeared clear, only 100 to 150 A granules associated with the periodic collagen striations were stained. This inverse variation between non collagenous proteoglycans and glycoproteins is discussed in relation to the mineralization process.