SPATIAL CHEMICAL-ANALYSIS OF DENTAL STAIN USING WAVELENGTH DISPERSIVESPECTROMETRY

Six extracted human teeth with naturally-formed neglected stain were a nalyzed for chemical constituents using wavelength dispersive spectrom etry (WDS), an electron microprobe technique. Spatial distribution, wi thin a few mu m resolution, of the compositional elements was obtained by line and map analyses, which provided relative concentrations of t he elements in stain-enamel complex. Absolute concentrations at differ ent locations across a specimen were obtained from quantitative analys is. Results showed that these neglected stains were highly calcified a nd contained a significant amount of organic matter (C, N, O, S), with traces of Fe and Cu. The tooth surface underneath the stain layer cou ld be easily distinguished by the higher Ca and P content, as well as by finite amounts of C and S. Corresponding areas of high concentratio ns between S and Fe/Cu were observed, which suggested the complex of s ulfur and metal ions as possible color-forming species. S was found to diffuse into surface enamel in the range of 10 mu m.