A histochemical study of the intertubular and peritubular matrices in normal human dentine

Serial ground sections of sound, recently erupted human teeth were stained with 0.0005 M methylene blue, 0.01–0.1% toluidine blue, 0.05–0.5% alcian blue at pH 2.6, 3.6 and 7.0, and with the periodic acid-Schiff method.

With methylene blue at pH 2.6 and 3.6, a zone of dentine about 20–25 μ wide, immediately adjacent to the predentine, was stained. The staining was in the intertubular matrix which also stained intensely with alcian blue and the PAS method and showed metachromasia at pH 3.6 with toluicline blue. This zone may represent the “intermediate dentine” of other workers, and appears to be rich in polysaccharide and especially in acid mucopolysaccharide. The rest of the intertubular matrix, external to the first zone, showed practically no staining with methylene blue or toluicline blue at pH 2.6 or 3.6, and a reduction in the depth of PAS staining. It is considered that calcification of the intertubular dentine is virtually completed in the first zone.

The peritubular matrix first appeared about 60–100 μ from the predentine-dentine junction and quickly reached its full width. The peritubular matrix stained intensely and metachromatically with methylene blue and toluicline blue at pH 2.6 and 3.6 and deeply with alcian blue at 2.6. Observations made suggest that the peritubular matrix rapidly attains a high level of calcification.

The formation and calcification of the intertubular and peritubular matrices appear to be entirely separate stages in dentine development.