1998 Volume 18 Issue 1 Pages 43-49
The transverse cut and polished surfaces of a cow longbone were observed by backscattered electron (BSE) imaging, and then they were treated with a combined treatment of sodium hypochlorite (NaOCl) and ethylenediamine tetra-acetic acid (EDTA). The samples were observed again by BSE or by scanning electron microscopy (SEM). The combined treatment strongly eroded young hypocalcified osteons, and they were compared with older osteons. Some young osteons before treatment contained hypocalcified lines along the Haversian lamellas. The hypocalcified lines were more strongly eroded than the neighboring lines in the NaOCl-EDTA/ BSE method. In addition, a developing small osteon or a Haversian lamella showed a loose structure in the NaOCl-EDTA/SEM method. Thus, it was revealed that hypocalcified osteons and incremental lines, containing either a large or a smaller amount of collagen fibers, were strongly eroded by the combined treatment of NaOCl and EDTA. From such findings, it is suggested that the hypocalcified lines of spherical and linear laminate structures in human dentin are more strongly eroded than the hypercalcified lines in the NaOCl-EDTA/SEM method. Though we have previously suggested the positive correlation between the concentration of collagen fibers and the degree of calcification in the dentin, the correlation may be negative if the lower the concentration of collagen fibers is, the higher the degree of calcification as suggested by an author. On this correlation, further investigations will be necessary.
