General Histology and Cytology
The effect of osmium postfixation and uranyl and lead staining on the ultrastrucure of young enamel in the rat incisor
Article first published online: 8 FEB 2005
Copyright © 1983 Wiley-Liss, Inc.
The Anatomical Record
Volume 207, Issue 1, pages 1–16, September 1983
How to Cite
Nanci, A., Bai, P. and Warshawsky, H. (1983), The effect of osmium postfixation and uranyl and lead staining on the ultrastrucure of young enamel in the rat incisor. Anat. Rec., 207: 1–16. doi: 10.1002/ar.1092070102
- Issue published online: 8 FEB 2005
- Article first published online: 8 FEB 2005
- Manuscript Accepted: 15 MAY 1983
- Manuscript Received: 27 SEP 1982
Enamel crystallites are electron opaque without osmium or heavy metal staining and give a crystalline electron diffraction pattern. Since the opacity and diffraction pattern are abolished from ultrathin sections of young enamel by floating on distilled water (Bishop and Warshawsky, 1982), the possibility that aqueous staining may also remove crystallites was tested. In addition, the effect of osmium postifixation on crystallite structure was examined.
Rat incisors fixed by perfusion with a mixture of aldehydes were either nonosmicated or osmicated prior to dehydration. Incisor segments in the region of inner enamel secretion were embedded in the same Epon block to ensure reliable comparison. Osmicated enamel was more intensely stained with toluidine blue and more electron opaque than nonosmicated enamel. No other structural differences were seen. However, crystallites in osmicated enamel were more resistant to grid demineralization and electron beam damage. Routine staining was done by floating sections on solutions of uranyl acetate and lead citrate; sections were also floated on similar solutions from which the heavy metals were omitted. These solutions removed the electron opaque crystallites from the youngest enamel. Stained sections showed electron opaque crystallite-like structure similar to unstained enamel. When sections that were extracted by the solutions from which the metals were omitted were restained, they appeared identical to routinely stained enamel. It was conclud that staining of young enamel removes the crystallites and reveals only the organic matrix.