title: Investigations into black extrinsic tooth stain.
abstract: An investigation has been carried out into the nature of the black pigment in black extrinsic tooth stain. The results suggest that the black material is a ferric salt, probably ferric sulfide, formed by the reaction between hydrogen sulfide produced by bacterial action and iron in the saliva or gingival exudate.
mesh_terms: D000293:Adolescent; D001419:Bacteria / Q000378:metabolism*; D055598:Chemical Phenomena; D002621:Chemistry; D003773:Dental Plaque / Q000032:analysis*; D005260:Female; D005290:Ferric Compounds / Q000032:analysis* / Q000378:metabolism; D006801:Humans; D006862:Hydrogen Sulfide / Q000378:metabolism; D007501:Iron / Q000032:analysis* / Q000378:metabolism; D008297:Male; D010860:Pigments, Biological / Q000032:analysis*; D013440:Sulfides; D014075:Tooth Discoloration / Q000209:etiology*
chemical_list: D005290:Ferric Compounds; D010860:Pigments, Biological; D013440:Sulfides; D007501:Iron; D006862:Hydrogen Sulfide