All of the following result in endogenous pigmentation of teeth except:

Discoloration of either deciduous or permanent teeth may occur as result of tetracycline deposition during prophylactic or therapeutic or therapeutic regimens instituted either in the pregnant female or postpartum in the infant. Tetracycline and its homologues have a selective affinity for deposition in bone and tooth substance, possibly through the formation of a complex with calcium ions in the surface of the microcrystals of hydroxyapatite.